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Title: Fungi: Their Nature and Uses
Author: Cooke, M. C. (Mordecai Cubitt), 1825-1914
Language: English
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Copyright Status: Not copyrighted in the United States. If you live elsewhere check the laws of your country before downloading this ebook. See comments about copyright issues at end of book.

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THE INTERNATIONAL SCIENTIFIC SERIES.

VOLUME XV.



THE INTERNATIONAL SCIENTIFIC SERIES.

_Works already Published._


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   XV. FUNGI; their Nature, Influence, and Uses. By M. C. Cooke, M.A.,
        LL.D. Edited by Rev. M. J. Berkeley, M.A., F.L.S. With
        109 Illustrations. (_In press._)

  XVI. OPTICS. By Professor Lommel, University of Erlangen.
        (_In press._)



THE INTERNATIONAL SCIENTIFIC SERIES.



FUNGI:

THEIR

NATURE AND USES.


BY
M. C. COOKE, M.A., LL.D.

EDITED BY
THE REV. M. J. BERKELEY, M.A., F.L.S.



NEW YORK:
D. APPLETON AND COMPANY,
549 AND 551 BROADWAY.
1875.



PREFACE BY THE EDITOR.


As my name appears on the title-page of this volume, it is necessary
that I should exactly state what part I had in its preparation. I had
no doubt originally engaged to undertake the work myself; but finding,
from multiplicity of engagements and my uncertain health, that I could
not accomplish it satisfactorily, I thought the best course I could
take was to recommend Mr. Cooke to the publishers; a gentleman well
known, not only in this country, but in the United States. The whole
of the work has therefore been prepared by himself, the manuscript and
proof sheets being submitted to me from time to time, in which I
merely suggested such additions as seemed needful, subjoining
occasionally a few notes. As the work is intended for students, the
author has had no hesitation in repeating what has been stated in
former chapters where it has been thought to prove useful. I have no
doubt that the same high character will justly apply to this as to Mr.
Cooke's former publications, and especially to his "Handbook of
British Fungi."

                                                       M. J. BERKELEY.

SIBBERTOFT,

  _November 23, 1874._



CONTENTS.


                                                                  PAGE
     I. NATURE OF FUNGI.                                             1
    II. STRUCTURE.                                                  17
    III CLASSIFICATION                                              64
    IV. USES.                                                       82
     V. NOTABLE PHENOMENA.                                         105
    VI. THE SPORE AND ITS DISSEMINATION.                           119
   VII. GERMINATION AND GROWTH.                                    137
  VIII. SEXUAL REPRODUCTION.                                       163
    IX. POLYMORPHISM.                                              182
     X. INFLUENCES AND EFFECTS.                                    209
    XI. HABITATS.                                                  233
   XII. CULTIVATION.                                               253
  XIII. GEOGRAPHICAL DISTRIBUTION.                                 266
   XIV. COLLECTION AND PRESERVATION.                               287
        INDEX.                                                     295



LIST OF ILLUSTRATIONS.


   FIG.                                                           PAGE
     1. Agaric in Process of Growth.                                17
     2. Section of Common Mushroom.                                 21
     3. Sterile cells, Basidia, Cystidium, from _Gomphidius_.       21
     4. _Polyporus giganteus_ (reduced).                            23
     5. _Hydnum repandum._                                          24
     6. _Calocera viscosa._                                         24
     7. _Tremella mesenterica._                                     24
     8. Basidia and spores of _Phallus_.                            28
     9. Basidia and spores of _Lycoperdon_.                         29
    10. Threads of _Trichia_.                                       31
    11. _Arcyria incarnata_, with portion of threads and spore.     33
    12. _Diachæa elegans._                                          34
    13. _Cyathus vernicosus._                                       34
    14. _Cyathus_, Sporangia and spores.                            35
    15. _Asterosporium Hoffmanni._                                  36
    16. Barren Cysts and Pseudospores of _Lecythea_.                36
    17. _Coleosporium Tussilaginis._                                36
    18. _Melampsora salicina_, pseudospores of                      36
    19. _Cystopus candidus_, conidia of                             38
    20. _Xenodochus carbonarius_, pseudospore.                      38
    21. _Phragmidium bulbosum_, pseudospores.                       38
    22. Pseudospores of _Puccinia_.                                 40
    23. _Thecaphora hyalina_, pseudospores.                         41
    24. _Æcidium Berberidis_, peridia of                            41
    25. _Helminthosporium molle_, threads and spores.               42
    26. _Acrothecium simplex._                                      44
    27. _Peronospora Arenariæ._                                     44
    28. _Polyactis cinerea._                                        47
    29. _Peziza Fuckeliana_, with ascus and sporidia.               47
    30. _Penicillium chartarum._                                    50
    31. _Mucor mucedo_, with sporangia.                             50
    32. Small portion of _Botrytis Jonesii_.                        54
    33. Section of cup of _Ascobolus_.                              57
    34. Asci, sporidia, and paraphyses of _Ascobolus_.              59
    35. Perithecium of _Sphæria_.                                   61
    36. _Uncinula adunca_, conceptacle with appendages.             62
    37. _Agaricus nudus._                                           66
    38. _Scleroderma vulgare_, Fr.                                  69
    39. _Ceuthospora phacidioides._                                 69
    40. _Rhopalomyces candidus._                                    74
    41. _Mucor caninus._                                            75
    42. _Sphæria aquila_, cluster of perithecia.                    78
    43. _Morchella gigaspora_, from Kashmir.                        99
    44. _Cyttaria Gunnii_                                          101
    45. Spores of Agarics                                          121
    46. Spores of _Lactarius_                                      121
    46a. Spores of _Gomphidius_                                    122
    47. Spores of _Polyporus_, _Boletus_, and _Hydnum_.            122
    48. _Diachea elegans_, capellitium of                          123
    49. Spore of _Hendersonia polycystis_.                         126
    50. Spores of _Dilophospora graminis_.                         126
    51. Spores of _Discosia_.                                      126
    52. Spore of _Prosthemium betulinum_.                          126
    53. Spore of _Stegonosporium cellulosum_.                      126
    54. Stylospores of _Coryneum disciforme_.                      126
    55. Spores of _Asterosporium Hoffmanni_.                       126
    56. Spores of _Pestalozzia_.                                   126
    57. _Bispora monilioides_, concatenate spores                  126
    58. Pseudospores of _Thecaphora hyalina_.                      128
    59. Pseudospores of _Puccinia_.                                128
    60. Pseudospores of _Triphragmium_.                            128
    61. Pseudospores of _Phragmidium bulbosum_.                    128
    62. Winter spores of _Melampsora salicina._                    128
    63. Spores of _Helicocoryne_.                                  129
    64. Sporidium of _Genea verrucosa_.                            130
    65. Alveolate sporidium of _Tuber_.                            130
    66. Asci, sporidia, and paraphyses of _Ascobolus_.             131
    67. Sporidium of _Ostreichnion Americanum_.                    132
    68. Ascus and sporidia of _Hypocrea_.                          135
    69. Sporidium of _Sphæria ulnaspora_.                          135
    70. Sporidia of _Valsa profusa_.                               135
    71. Sporidia of _Massaria foedans_.                            135
    72. Sporidium of _Melanconis bicornis_.                        135
    73. Caudate sporidia of _Sphæria fimiseda_.                    135
    74. Sporidia of _Valsa thelebola_.                             135
    75. Sporidia of _Valsa taleola_.                               135
    76. Sporidium of _Sporormia intermedia_.                       135
    77. Asci and sporidia of _Sphæria_ (_Pleospora_)
            _herbarum_.                                            135
    78. Sporidium of _Sphæria putaminum_.                          135
    79. Basidia and spores of _Exidia spiculosa_.                  139
    80. Germinating spore and corpuscles of _Dacrymyces_.          140
    81. Germination of _Æcidium Euphorbia_.                        142
    82. Germinating pseudospores of _Coleosporium Sonchi_.         144
    83. Germinating pseudospore of _Melampsora betulina_.          144
    84. Germinating pseudospore of _Uromyce appendiculatus_.       145
    85. Germinating pseudospore of _Puccinia Moliniæ_.             146
    86. Germinating pseudospore of _Triphragmium Ulmariæ_.         146
    87. Germinating pseudospore of _Phragmidium bulbosum_.         147
    88. Germinating pseudospores of _Podisoma Juniperi_.           149
    89. Germinating pseudospore of _Tilletia caries_.              150
    90. Pseudospore of _Ustilago receptaculorum_ in germination,
            and secondary spores in conjugation.                   151
    91. Conidia and zoospores of _Cystopus candidus_.              151
    92. Resting spore of _Cystopus candidus_ with zoospores.       152
    93. Zygospores of _Mucor phycomyces_.                          158
    94. Sporidium of _Ascobolus_ germinating.                      161
    95. Zygospore of _Mucor_.                                      164
    96. Zygospore of _Rhizopus_ in different stages.               166
    97. Conjugation in _Achlya racemosa_.                          169
    98. Conjugation in _Peronospora._                              171
    99. Antheridia and oogonium of _Peronospora_.                  172
   100. Conjugation in _Peziza omphalodes_.                        176
   100a. Formation of conceptacle in _Erysiphe_.                   176
   101. _Tilletia caries_ with conjugating cells.                  178
   102. _Aspergillus glaucus_ and _Eurotium_.                      190
   103. _Erysiphe cichoracearum_, receptacle and mycelium.         192
   104. Twig with _Tubercularia_ and _Nectria_.                    193
   105. Section of _Tubercularia_ with conidia.                    193
   106. D. _Nectria_ with _Tubercularia_, ascus and paraphyses.    195
   107. Cells and pseudospores of _Æcidium berberidis_.            201
   108. Cells and pseudospores of _Æcidium graveolens_.            201
   109. _Torrubia militaris_ on pupa of a moth.                    243



FUNGI

THEIR NATURE, USES, INFLUENCES, ETC.



I.

NATURE OF FUNGI.


The most casual observer of Nature recognizes in almost every instance
that comes under his notice in every-day life, without the aid of
logical definition, the broad distinctions between an animal, a plant,
and a stone. To him, the old definition that an animal is possessed of
life and locomotion, a plant of life without locomotion, and a mineral
deficient in both, seems to be sufficient, until some day he travels
beyond the circuit of diurnal routine, and encounters a sponge or a
zoophyte, which possesses only one of his supposed attributes of
animal life, but which he is assured is nevertheless a member of the
animal kingdom. Such an encounter usually perplexes the neophyte at
first, but rather than confess his generalizations to have been too
gross, he will tenaciously contend that the sponge must be a plant,
until the evidence produced is so strong that he is compelled to
desert his position, and seek refuge in the declaration that one
kingdom runs into the other so imperceptibly that no line of
demarcation can be drawn between them. Between these two extremes of
broad distinction, and no distinction, lies the ground occupied by the
scientific student, who, whilst admitting that logical definition
fails in assigning briefly and tersely the bounds of the three
kingdoms, contends that such limits exist so positively, that the
universal scientific mind accepts the recognized limit without
controversy or contradiction.

In like manner, if one kingdom be made the subject of inquiry, the
same difficulties will arise. A flowering plant, as represented by a
rose or a lily, will be recognized as distinct from a fern, a seaweed,
or a fungus. Yet there are some flowering plants which, at first
sight, and without examination, simulate cryptogams, as, for example,
many _Balanophoræ_, which the unscientific would at once class with
fungi. It is nevertheless true that even the incipient botanist will
accurately separate the phanerogams from the cryptogams, and by means
of a little more, but still elementary knowledge, distribute the
latter amongst ferns, mosses, fungi, lichens, and algæ, with
comparatively few exceptions. It is true that between fungi and
lichens there exists so close an affinity that difficulties arise, and
doubts, and disputations, regarding certain small groups or a few
species; but these are the exception, and not the rule. Botanists
generally are agreed in recognizing the five principal groups of
Cryptogamia, as natural and distinct. In proportion as we advance from
comparison of members of the three kingdoms, through that of the
primary groups in one kingdom, to a comparison of tribes, alliances,
and orders, we shall require closer observation, and more and more
education of the eye to see, and the mind to appreciate, relationships
and distinctions.

We have already assumed that fungi are duly and universally admitted,
as plants, into the vegetable kingdom. But of this fact some have even
ventured to doubt. This doubt, however, has been confined to one order
of fungi, except, perhaps, amongst the most illiterate, although now
the animal nature of the _Myxogastres_ has scarcely a serious advocate
left. In this order the early condition of the plant is pulpy and
gelatinous, and consists of a substance more allied to sarcode than
cellulose. De Bary insinuated affinities with _Amoeba_,[A] whilst
Tulasne affirmed that the outer coat in some of these productions
contained so much carbonate of lime that strong effervescence took
place on the application of sulphuric acid. Dr. Henry Carter is well
known as an old and experienced worker amongst amoeboid forms of
animal life, and, when in Bombay, he devoted himself to the
examination of the _Myxogastres_ in their early stage, and the result
of his examinations has been a firm conviction that there is no
relationship whatever between the _Myxogastres_ and the lower forms of
animal life. De Bary has himself very much modified, if not wholly
abandoned, the views once propounded by him on this subject. When
mature, and the dusty spores, mixed with threads, sometimes spiral,
are produced, the _Myxogastres_ are so evidently close allies of the
_Lycoperdons_, or Puffballs, as to leave no doubt of their affinities.
It is scarcely necessary to remark that the presence of zoospores is
no proof of animal nature, for not only do they occur in the white
rust (_Cystopus_), and in such moulds as _Peronospora_,[B] but are
common in algæ, the vegetable nature of which has never been
disputed.

There is another equally important, but more complicated subject to
which we must allude in this connection. This is the probability of
minute fungi being developed without the intervention of germs, from
certain solutions. The observations of M. Trécul, in a paper laid
before the French Academy, have thus been summarized:--1. Yeast cells
may be formed in the must of beer without spores being previously
sown. 2. Cells of the same form as those of yeast, but with different
contents, arise spontaneously in simple solution of sugar, or to which
a little tartrate of ammonia has been added, and these cells are
capable of producing fermentation in certain liquids under favourable
conditions. 3. The cells thus formed produce _Penicillium_ like the
cells of yeast. 4. On the other hand, the spores of _Penicillium_ are
capable of being transformed into yeast.[C] The interpretation of this
is, that the mould _Penicillium_ may be produced from a sugar
solution by "spontaneous generation," and without spore or germ of any
kind. The theory is, that a molecular mass which is developed in
certain solutions or infusions, may, under the influence of different
circumstances, produce either animalcules or fungi. "In all these
cases, no kind of animalcule or fungus is ever seen to originate from
preexisting cells or larger bodies, but always from molecules."[D] The
molecules are said to form small masses, which soon melt together to
constitute a globular body, from which a process juts out on one side.
These are the so-called _Torulæ_,[E] which give off buds which are
soon transformed into jointed tubes of various diameters, terminating
in rows of sporules, _Penicillium_, or capsules containing numerous
globular seeds, _Aspergillus_ (_sic_).

This is but another mode of stating the same thing as above referred
to by M. Trécul, that certain cells, resembling yeast cells (_Torula_),
are developed spontaneously, and that these ultimately pass through the
form of mould called _Penicillium_ to the more complex _Mucor_ (which
the writer evidently has confounded with _Aspergillus_, unless he
alludes to the ascigerous form of _Aspergillus_, long known as
_Eurotium_). From what is now known of the polymorphism of fungi, there
would be little difficulty in believing that cells resembling yeast
cells would develop into _Penicillium_, as they do in _fact_ in what is
called the "vinegar plant," and that the capsuliferous, or higher
condition of this mould may be a _Mucor_, in which the sporules are
produced in capsules. The difficulty arises earlier, in the supposed
spontaneous origination of yeast cells from molecules, which result from
the peculiar conditions of light, temperature, &c., in which certain
solutions are placed. It would be impossible to review all the
arguments, or tabulate all the experiments, which have been employed
for and against this theory. It could not be passed over in silence,
since it has been one of the stirring questions of the day. The great
problem how to exclude all germs from the solutions experimented
upon, and to keep them excluded, lies at the foundation of the theory.
It must ever, as we think, be matter of doubt that all germs were not
excluded or destroyed, rather than one of belief that forms known to be
developed day by day from germs should under other conditions
originate spontaneously.

Fungi are veritably and unmistakably plants, of a low organization, it
is true, but still plants, developed from germs, somewhat analogous,
but not wholly homologous, to the seeds of higher orders. The process
of fertilization is still obscure, but facts are slowly and gradually
accumulating, so that we may hope at some not very distant period to
comprehend what as yet are little removed from hypotheses. Admitting
that fungi are independent plants, much more complex in their
relations and development than was formerly supposed, it will be
expected that certain forms should be comparatively permanent, that
is, that they should constitute good species. Here, also, efforts have
been made to develop a theory that there are no legitimate species
amongst fungi, accepting the terms as hitherto applied to flowering
plants. In this, as in allied instances, too hasty generalizations
have been based on a few isolated facts, without due comprehension of
the true interpretation of such facts and phenomena. Polymorphism will
hereafter receive special illustration, but meantime it may be well to
state that, because some forms of fungi which have been described, and
which have borne distinct names as autonomous species, are now proved
to be only stages or conditions of other species, there is no reason
for concluding that no forms are autonomous, or that fungi which
appear and are developed in successive stages are not, in their
entirety, good species. Instead, therefore, of insinuating that there
are no good species, modern investigation tends rather to the
establishment of good species, and the elimination of those that are
spurious. It is chiefly amongst the microscopic species that
polymorphism has been determined. In the larger and fleshy fungi
nothing has been discovered which can shake our faith in the species
described half a century, or more, ago. In the Agarics, for instance,
the forms seem to be as permanent and as distinct as in the flowering
plants. In fact, there is still no reason to dissent, except to a very
limited extent, from what was written before polymorphism was
accredited, that, "with a few exceptions only, it may without doubt be
asserted that more certain species do not exist in any part of the
organized world than amongst fungi. The same species constantly recur
in the same places, and if kinds not hitherto detected present
themselves, they are either such as are well known in other districts,
or species which have been overlooked, and which are found on better
experience to be widely diffused. There is nothing like chance about
their characters or growth."[F]

The parasitism of numerous minute species on living and growing plants
has its parallel even amongst phanerogams in the mistletoe and
broom-rape and similar species. Amongst fungi a large number are thus
parasitic, distorting, and in many cases ultimately destroying, their
host, burrowing within the tissues, and causing rust and smut in corn
and grasses, or even more destructive and injurious in such moulds as
those of the potato disease and its allies. A still larger number of
fungi are developed from decayed or decaying vegetable matter. These
are found in winter on dead leaves, twigs, branches, rotten wood, the
remains of herbaceous plants, and soil largely charged with
disintegrated vegetables. As soon as a plant begins to decay it
becomes the source of a new vegetation, which hastens its destruction,
and a new cycle of life commences. In these instances, whether
parasitic on living plants or developed on dead ones, the source is
still vegetable. But this is not always the case, so that it cannot be
predicated that fungi are wholly epiphytal. Some species are always
found on animal matter, leather, horn, bone, &c., and same affect such
unpromising substances as minerals, from which it would be supposed
that no nourishment could be obtained, not only hard gravel stones,
fragments of rock, but also metals, such as iron and lead, of which
more may be said when we come to treat of the habitats of fungi.
Although in general terms fungi may be described as "hysterophytal or
epiphytal mycetals deriving nourishment by means of a mycelium from
the matrix,"[G] there are exceptions to this rule with which the
majority accord.

Of the fungi found on animal substances, none are more extraordinary
than those species which attack insects. The white mould which in
autumn proves so destructive to the common house-fly may for the
present be omitted, as it is probably a condition of one of the
_Saprolegniei_, which some authors include with fungi, and others with
algæ. Wasps, spiders, moths, and butterflies become enveloped in a
kind of mould named _Isaria_, which constitutes the conidia of
_Torrubia_, a genus of club-shaped _Sphæriæ_ afterwards developed.
Some species of _Isaria_ and _Torrubia_ also affect the larvæ and pupæ
of moths and butterflies, converting the whole interior into a mass of
mycelium, and fructifying in a clavate head. It has been subject for
discussion whether in such instances the fungus commenced its
development during the life of the insect, and thus hastened its
death, or whether it resulted after death, and was subsequent to the
commencement of decay.[H] The position in which certain large moths
are found standing on leaves when infested with _Isaria_ resembles so
closely that of the house-fly when succumbing to _Sporendonema Muscæ_,
would lead to the conclusion that certainly in some cases the insect
was attacked by the fungus whilst still living; whilst in the case of
buried caterpillars, such as the New Zealand or British _Hepialus_, it
is difficult to decide. Whether in life or death in these instances,
it is clear that the silk-worm disease _Muscardine_ attacks the living
insect, and causes death. In the case of the _Guêpes végétantes_, the
wasp is said to fly about with the fungus partially developed.

In all fungi we may recognize a vegetative and a reproductive system:
sometimes the first only becomes developed, and then the fungus is
imperfect, and sometimes the latter is far more prominent than the
former. There is usually an agglomeration of delicate threads,
either jointed or not, which are somewhat analogous to the roots of
higher plants. These delicate threads permeate the tissues of
plants attacked by parasitic fungi, or they run over dead leaves
forming whitened patches, formerly bearing the name of _Himantia_,
but really the mycelium of some species of _Marasmius_. If checked
or disturbed, the process stops here, and only a mycelium of
interwoven threads is produced. In this condition the mycelium of one
species so much resembles that of another, that no accurate
determination can be made. If the process goes on, this mycelium gives
rise to the stem and cap of an agaricoid fungus, completing the
vegetative system. This in turn gives origin to a spore-bearing
surface, and ultimately the fruit is formed, and then the fungus is
complete; no fungus can be regarded as perfect or complete without
its reproductive system being developed. In some this is very
simple, in others it is as complex. In many of the moulds we have
miniature representatives of higher plants in the mycelium or
roots, stem, branches, and at length capsules bearing sporidia, which
correspond to seeds. It is true that leaves are absent, but these are
sometimes compensated by lateral processes or abortive branchlets.
A tuft of mould is in miniature a forest of trees. Although such a
definition may be deemed more poetic than accurate, more figurative
than literal, yet few could believe in the marvellous beauty of a
tuft of mould if they never saw it as exhibited under the microscope.
In such a condition no doubt could be entertained of its vegetable
character. But there is a lower phase in which these plants are
sometimes encountered; they may consist only of single cells, or
strings of cells, or threads of simple structure floating in
fluids. In such conditions only the vegetative system is probably
developed, and that imperfectly, yet some have ventured to give
names to isolated cells, or strings of cells, or threads of
mycelium, which really in themselves possess none of the elements
of correct classification--the vegetative system, even, being
imperfect, and consequently the reproductive is absent. As already
observed, no fungus is perfect without fruit of some kind, and the
peculiarities of structure and development of fruit form one of the
most important elements in classification. To attempt, therefore, to
give names to such imperfect fragments of undeveloped plants is
almost as absurd as to name a flowering plant from a stray
fragment of a root-fibril accidentally cast out of the ground--nay,
even worse, for identification would probably be easier. It is well to
protest at all times against attempts to push science to the verge
of absurdity; and such must be the verdict upon endeavours to
determine positively such incomplete organisms as floating cells,
or hyaline threads which may belong to any one of fifty species of
moulds, or after all to an alga. This leads us to remark, in
passing, that there are forms and conditions under which fungi may
be found when, fructification being absent--that is, the vegetative
system alone developed--they approximate so closely to algæ that it
is almost impossible to say to which group the organisms belong.

Finally, it is a great characteristic of fungi in general that they
are very rapid in growth, and rapid in decay. In a night a puffball
will grow prodigiously, and in the same short period a mass of paste
may be covered with mould. In a few hours a gelatinous mass of
_Reticularia_ will pass into a bladder of dust, or a _Coprinus_ will
be dripping into decay. Remembering this, mycophagists will take note
that a fleshy fungus which may be good eating at noon may undergo such
changes in a few hours as to be anything but good eating at night.
Many instances have been recorded of the rapidity of growth in fungi;
it may also be accepted as an axiom that they are, in many instances,
equally as rapid in decay.

The affinity between lichens and fungi has long been recognized to its
full and legitimate extent by lichenologists and mycologists.[I] In
the "Introduction to Cryptogamic Botany," it was proposed to unite
them in one alliance, under the name of _Mycetales_, in the same
manner as the late Dr. Lindley had united allied orders under
alliances in his "Vegetable Kingdom;" but, beyond this, there was no
predisposition towards the theory since propounded, and which, like
all new theories, has collected a small but zealous circle of
adherents. It will be necessary briefly to summarize this theory and
the arguments by which it is supported and opposed, inasmuch as it is
intimately connected with our subject.

As recently as 1868, Professor Schwendener first propounded his
views,[J] and then briefly and vaguely, that all and every individual
lichen was but an algal, which had collected about it a parasitic
fungal growth, and that those peculiar bodies which, under the name of
_gonidia_, were considered as special organs of lichens, were only
imprisoned algæ. In language which the Rev. J. M. Crombie[K] describes
as "pictorial," this author gave the general conclusion at which he
had arrived, as follows:--"As the result of my researches, all these
growths are not simple plants, not individuals in the usual sense of
the term; they are rather colonies, which consist of hundreds and
thousands of individuals, of which, however, only one acts as master,
while the others, in perpetual captivity, provide nourishment for
themselves and their master. This master is a fungus of the order
_Ascomycetes_, a parasite which is accustomed to live upon the work of
others; its slaves are green algæ, which it has sought out, or indeed
caught hold of, and forced into its service. It surrounds them, as a
spider does its prey, with a fibrous net of narrow meshes, which is
gradually converted into an impenetrable covering. While, however, the
spider sucks its prey and leaves it lying dead, the fungus incites the
algæ taken in its net to more rapid activity; nay, to more vigorous
increase." This hypothesis, ushered upon the world with all the
prestige of the Professor's name, was not long in meeting with
adherents, and the cardinal points insisted upon were--1st. That the
generic relationship of the coloured "gonidia" to the colourless
filaments which compose the lichen thallus, had only been assumed, and
not proved; 2nd. That the membrane of the gonidia was chemically
different from the membrane of the other tissues, inasmuch as the
first had a reaction corresponding to that of algæ, whilst the second
had that of fungi; 3rd. That the different forms and varieties of
gonidia corresponded with parallel types of algæ; 4th. That as the
germination of the spore had not been followed further than the
development of a hypothallus, it might be accounted for by the absence
of the essential algal on which the new organism should become
parasitic; 5th. That there is a striking correspondence between the
development of the fruit in lichens and in some of the sporidiiferous
fungi (_Pyrenomycetes_).

These five points have been combated incessantly by lichenologists,
who would really be supposed by ordinary minds to be the most
practically acquainted with the structure and development of these
plants, in opposition to the theorists. It is a fact which should have
some weight, that no lichenologist of repute has as yet accepted the
theory. In 1873 Dr. E. Bornet[L] came to the aid of Schwendener, and
almost exhausted the subject, but failed to convince either the
practised lichenologist or mycologist. The two great points sought to
be established are these, that what we call lichens are compound
organisms, not simple, independent vegetable entities; and that this
compound organism consists of unicellular algæ, with a fungus
parasitic upon them. The coloured gonidia which are found in the
substance, or thallus of lichens, are the supposed algæ; and the
cellular structure which surrounds, encloses, and imprisons the
gonidia is the parasitic fungus, which is parasitic on something
infinitely smaller than itself, and which it entirely and absolutely
isolates from all external influences.

Dr. Bornet believed himself to have established that every gonidium of
a lichen may be referred to a species of algæ, and that the connection
between the hypha and gonidia is of such a nature as to exclude all
possibility of the one organ being produced by the other. This he
thinks is the only way in which it can be accounted for that the
gonidia of diverse lichens should be almost identical.

Dr. Nylander, in referring to this hypothesis of an imprisoned
algal,[M] writes: "The absurdity of such an hypothesis is evident from
the very consideration that it cannot be the case that an organ
(gonidia) should at the same time be a parasite on the body of which
it exercises vital functions; for with equal propriety it might be
contended that the liver or the spleen constitutes parasites of the
mammiferæ. Parasite existence is autonomous, living upon a foreign
body, of which nature prohibits it from being at the same time an
organ. This is an elementary axiom of general physiology. But
observation directly made teaches that the green matter originally
arises within the primary chlorophyll- or phycochrom-bearing cellule,
and consequently is not intruded from any external quarter, nor arises
in any way from any parasitism of any kind. The cellule at first is
observed to be empty, and then, by the aid of secretion, green matter
is gradually produced in the cavity and assumes a definite form. It
can, therefore, be very easily and evidently demonstrated that the
origin of green matter in lichens is entirely the same as in other
plants." On another occasion, and in another place, the same eminent
lichenologist remarks,[N] as to the supposed algoid nature of
gonidia--"that such an unnatural existence as they would thus pass,
enclosed in a prison and deprived of all autonomous liberty, is not
at all consonant with the manner of existence of the other algæ, and
that it has no parallel in nature, for nothing physiologically
analogous occurs anywhere else. Krempelhuber has argued that there are
no conclusive reasons against the assumption that the lichen-gonidia
may be self-developed organs of the lichen proper rather than algæ,
and that these gonidia can continue to vegetate separately, and so be
mistaken for unicellular algæ." In this Th. Fries seems substantially
to concur. But there is one strong argument, or rather a repetition of
an argument already cited, placed in a much stronger light, which is
employed by Nylander in the following words:--"So far are what are
called algæ, according to the turbid hypothesis of Schwendener, from
constituting true algæ, that on the contrary it may be affirmed that
they have a lichenose nature, whence it follows that these pseudo-algæ
are in a systematic arrangement to be referred rather to the lichens,
and that the class of algæ hitherto so vaguely limited should be
circumscribed by new and truer limits."

As to another phase in this question, there are, as Krempelhuber
remarks, species of lichens which in many countries do not fructify,
and whose propagation can only be carried on by means of the soredia,
and the hyphæ of such could in themselves alone no more serve for
propagation than the hyphæ from the pileus or stalk of an Agaric,
while it is highly improbable that they could acquire this faculty by
interposition of a foreign algal. On the other hand he argues: "It is
much more conformable to nature that the gonidia, as self-developed
organs of the lichens, should, like the spores, enable the hyphæ
proceeding from them to propagate the individual."[O]

A case in point has been adduced[P] in which gonidia were produced by
the hypha, and the genus _Emericella_,[Q] which is allied to _Husseia_
in the _Trichogastres_, shows a structure in the stem exactly
resembling _Palmella botryoides_ of Greville, and to what occurs in
_Synalyssa_. _Emericella_, with one or two other genera, must,
however, be considered as connecting _Trichogastres_ with lichens, and
the question cannot be considered as satisfactorily decided till a
series of experiments has been made on the germination of lichen
spores and their relation to free algæ considered identical with
gonidia. Mr. Thwaites was the first to point out[R] the relation of
the gonidia in the different sections of lichens to different types of
supposed algæ. The question cannot be settled by mere _à priori_
notions. It is, perhaps, worthy of remark that in _Chionyphe Carteri_
the threads grow over the cysts exactly as the hypha of lichens is
represented as growing over the gonidia.

Recently, Dr. Thwaites has communicated his views on one phase of this
controversy,[S] which will serve to illustrate the question as seen
from the mycological side. As is well known, this writer has had
considerable experience in the study of the anatomy and physiology of
all the lower cryptogamia, and any suggestion of his on such a subject
will at least commend itself to a patient consideration.

"According to our experience," he writes, "I think parasitic fungi
invariably produce a sad effect upon the tissues they fix themselves
upon or in. These tissues become pale in colour, and in every respect
sickly in appearance. But who has ever seen the gonidia of lichens the
worse for having the 'hypha' growing amongst them? These gonidia are
always in the plumpest state, and with the freshest, healthiest colour
possible. Cannot it enter into the heads of these most patient and
excellent observers, that a cryptogamic plant may have two kinds of
tissue growing side by side, without the necessity of one being
parasitic upon the other, just as one of the higher plants may have
half a dozen kinds of tissue making up its organization? The
beautifully symmetrical growth of the same lichens has seemed to me a
sufficient argument against one portion being parasitic upon another,
but when we see all harmony and robust health, the idea that one
portion is subsisting parasitically upon another appears to me to be a
perfect absurdity."

It appears to us that a great deal of confusion and a large number of
errors which creep into our modern generalizations and hypotheses, may
be traced to the acceptance of analogies for identities. How many
cases of mistaken identity has the improvement of microscopes revealed
during the past quarter of a century. This should at least serve as a
caution for the future.

Apart, however, from the "gonidia," whatever they may be, is the
remainder of the lichen a genuine fungus? Nylander writes, "The
anatomical filamentose elements of lichens are distinguished by
various characters from the hyphæ of fungi. They are firmer, elastic,
and at once present themselves in the texture of lichens. On the other
hand, the hyphæ of fungi are very soft, they possess a thin wall, and
are not at all gelatinous, while they are immediately dissolved by the
application of hydrate of potash, &c."[T]

Our own experience is somewhat to the effect, that there are some few
lichens which are doubtful as to whether they are fungi or lichens,
but, in by far the majority of cases, there is not the slightest
difficulty in determining, from the peculiar firmness and elasticity
of the tissues, minute peculiarities which the practised hand can
detect rather than describe, and even the general character of the
fruit that they differ materially from, though closely allied to
fungi. We have only experience to guide us in these matters, but that
is something, and we have no experience in fungi of anything like a
_Cladonia_, however much it may resemble a _Torrubia_ or _Clavaria_.
We have _Pezizæ_ with a subiculum in the section _Tapesia_, but the
veriest tyro would not confound them with species of _Parmelia_. It is
true that a great number of lichens, at first sight, and casually,
resemble species of the _Hysteriacei_, but it is no less strange than
true, that lichenologists and mycologists know their own sufficiently
not to commit depredations on each other.

Contributions are daily being made to this controversy, and already
the principal arguments on both sides have appeared in an English
dress,[U] hence it will be unnecessary to repeat those which are
modifications only of the views already stated, our own conclusions
being capable of a very brief summary: that lichens and fungi are
closely related the one to the other, but that they are not identical;
that the "gonidia" of lichens are part of the lichen-organization, and
consequently are not algæ, or any introduced bodies; that there is no
parasitism; and that the lichen thallus, exclusive of gonidia, is
wholly unknown amongst fungi.

The Rev. J. M. Crombie has therefore our sympathies in the remark with
which his summary of the gonidia controversy closes, in which he
characterizes it as a "sensational romance of lichenology," of the
"unnatural union between a captive algal damsel and a tyrant fungal
master."

   [A] De Bary, "Des Myxomycètes," in "Ann. des Sci. Nat." 4 sér. xi. p.
       153; "Bot. Zeit." xvi. p. 357. De Bary's views are controverted
       by M. Wigand in "Ann. des Sci. Nat." 4 sér. (Bot.) xvi. p. 255,
       &c.

   [B] De Bary, "Recherches sur le Developpement de quelques Champignons
       Parasites," in "Ann. des Sci. Nat." 4 sér. (Bot.) xx. p. 5.

   [C] "Popular Science Review," vol. viii. p. 96.

   [D] Dr. J. H. Bennett "On the Molecular Origin of Infusoria," p. 56.

   [E] They have, however, no close relation with real _Torulæ_, such as
       _T. monilioides_, &c.--COOKE'S _Handbook_, p. 477.

   [F] Berkeley's "Outlines of British Fungology," p. 24.

   [G] Berkeley's "Introduction to Cryptogamic Botany," p. 235.

   [H] Gray, "Notices of Insects which form the Basis of Fungoid
       Parasites."

   [I] On the relation or connection between fungi and lichens, H. C.
       Sorby has some pertinent remarks in his communication to the
       Royal Society on "Comparative Vegetable Chromatology"
       (Proceedings Royal Society, vol. xxi. 1873, p. 479), as one
       result of his spectroscopic examinations. He says, "Such being
       the relations between the organs of reproduction and the
       foliage, it is to some extent possible to understand the
       connection between parasitic plants like fungi, which do not
       derive their support from the constructive energy of their
       fronds, and those which are self-supporting and possess true
       fronds. In the highest classes of plants the flowers are
       connected with the leaves, more especially by means of
       xanthophyll and yellow xanthophyll, whereas in the case of
       lichens the apothecia contain very little, if any, of those
       substances, but a large amount of the lichenoxanthines so
       characteristic of the class. Looking upon fungi from this
       chromatological point of view, they bear something like the
       same relation to lichens that the petals of a leafless
       parasitic plant would bear to the foliage of one of normal
       character--that is to say, they are, as it were, the coloured
       organs of reproduction of parasitic plants of a type closely
       approaching that of lichens, which, of course, is in very
       close, if not in absolute agreement with the conclusions drawn
       by botanists from entirely different data."

   [J] Schwendener, "Untersuchungen über den Flechtenthallus."

   [K] Crombie (J. M.) "On the Lichen-Gonidia Question," in "Popular
       Science Review" for July, 1874.

   [L] Bornet, (E.), "Recherches sur les Gonidies des Lichens," in "Ann.
       des Sci. Nat." 1873, 5 sér. vol. xvii.

   [M] Nylander, "On the Algo-Lichen Hypothesis," &c., in "Grevillea,"
       vol. ii. (1874), No. 22, p. 146.

   [N] In Regensburg "Flora," 1870, p. 92.

   [O] Rev. J. M. Crombie, in "Popular Science Review," July, 1874.

   [P] Berkeley's "Introduction to Cryptogamic Botany," p. 373, fig.
       78_a._

   [Q] Berkeley's "Introduction," p. 341, fig. 76.

   [R] "Annals and Magazine of Natural History," April, 1849.

   [S] In "Gardener's Chronicle" for 1873, p. 1341.

   [T] "Grevillea," vol ii. p. 147, in note.

   [U] W. Archer, in "Quart. Journ. Micr. Sci." vol. xiii. p. 217; vol.
       xiv. p. 115. Translation of Schwendener's "Nature of the
       Gonidia of Lichens," in same journal, vol. xiii. p. 235.



II.

STRUCTURE.


Without some knowledge of the structure of fungi, it is scarcely
possible to comprehend the principles of classification, or to
appreciate the curious phenomena of polymorphism. Yet there is so
great a variety in the structure of the different groups, that this
subject cannot be compressed within a few paragraphs, neither do we
think that this would be desired if practicable, seeing that the
anatomy and physiology of plants is, in itself, sufficiently important
and interesting to warrant a rather extended and explicit survey. In
order to impart as much practical utility as possible to this chapter,
it seems advisable to treat some of the most important and typical
orders and suborders separately, giving prominence to the features
which are chiefly characteristic of those sections, following the
order of systematists as much as possible, whilst endeavouring to
render each section independent to a considerable extent, and complete
in itself. Some groups naturally present more noteworthy features than
others, and will consequently seem to receive more than their
proportional share of attention, but this seeming inequality could
scarcely have been avoided, inasmuch as hitherto some groups have been
more closely investigated than others, are more intimately associated
with other questions, or are more readily and satisfactorily examined
under different aspects of their life-history.

[Illustration: FIG. 1.--Agaric in Process of Growth.]

AGARICINI.--For the structure that prevails in the order to which the
mushroom belongs, an examination of that species will be almost
sufficient. Here we shall at once recognize three distinct parts
requiring elucidation, viz. the rooting slender fibres that traverse
the soil, and termed the _mycelium_, or spawn, the stem and cap or
pileus, which together constitute what is called the _hymenophore_,
and the plates or gills on the under surface of the cap, which bear
the _hymenium_. The earliest condition in which the mushroom can be
recognized as a vegetable entity is in that of the "spawn" or
mycelium, which is essentially an agglomeration of vegetating spores.
Its normal form is that of branched, slender, entangled, anastomosing,
hyaline threads. At certain privileged points of the mycelium, the
threads seem to be aggregated, and become centres of vertical
extension. At first only a small nearly globose budding, like a grain
of mustard seed, is visible, but this afterwards increases rapidly,
and other similar buddings or swellings appear at the base.[A] These
are the young hymenophore. As it pushes through the soil, it
gradually loses its globose form, becomes more or less elongated, and
in this condition a longitudinal section shows the position of the
future gills in a pair of opposite crescent-shaped darker-coloured
spots near the apex. The dermal membrane, or outer skin, seems to be
continuous over the stem and the globose head. At present, there is no
external evidence of an expanded pileus and gills; a longitudinal
section at this stage shows that the gills are being developed, that
the pileus is assuming its cap-like form, that the membrane stretching
from the stem to the edge of the young pileus is separating from the
edge of the gills, and forming a _veil_, which, in course of time,
will separate below and leave the gills exposed. When, therefore, the
mushroom has arrived almost at maturity, the pileus expands, and in
this act the veil is torn away from the margin of the cap, and remains
for a time like a collar around the stem. Fragments of the veil often
remain attached to the margin of the pileus, and the collar adherent
to the stem falls back, and thenceforth is known as the _annulus_ or
ring. We have in this stage the fully-developed hymenophore,--the stem
with its ring, supporting an expanded cap or pileus, with gills on the
under surface bearing the hymenium.[B] A longitudinal section cut
through the pileus and down the stem, gives the best notion of the
arrangement of the parts, and their relation to the whole. By this
means it will be seen that the pileus is continuous with the stem,
that the substance of the pileus descends into the gills, and that
relatively the substance of the stem is more fibrous than that of the
pileus. In the common mushroom the ring is very distinct surrounding
the stem, a little above the middle, like a collar. In some Agarics
the ring is very fugacious, or absent altogether. The form of the
gills, their mode of attachment to the stem, their colour, and more
especially the colour of the spores, are all very important features
to be attended to in the discrimination of species, since they vary in
different species. The whole substance of the Agaric is cellular. A
longitudinal slice from the stem will exhibit under the microscope
delicate tubular cells, the general direction of which is lengthwise,
with lateral branches, the whole interlacing so intimately that it is
difficult to trace any individual thread very far in its course. It
will be evident that the structure is less compact as it approaches
the centre of the stem, which in many species is hollow. The
_hymenium_ is the spore-bearing surface, which is exposed or naked,
and spread over the gills. These plates are covered on all sides with
a delicate membrane, upon which the reproductive organs are developed.
If it were possible to remove this membrane in one entire piece and
spread it out flat, it would cover an immense surface, as compared
with the size of the pileus, for it is plaited or folded like a lady's
fan over the whole of the gill-plates, or lamellæ, of the fungus.[C]
If the stem of a mushroom be cut off close to the gills, and the cap
laid upon a sheet of paper, with the gills downwards, and left there
for a few hours, when removed a number of dark radiating lines will be
deposited upon the paper, each line corresponding with the interstices
between one pair of gills. These lines are made up of spores which
have fallen from the hymenium, and, if placed under the microscope,
their character will at once be made evident. If a fragment of the
hymenium be also submitted to a similar examination, it will be found
that the whole surface is studded with spores. The first peculiarity
which will be observed is, that these spores are almost uniformly in
groups of four together. The next feature to be observed is, that each
spore is borne upon a slender stalk or sterigma, and that four of
these sterigmata proceed from the apex of a thicker projection, from
the hymenium, called a _basidium_, each basidium being the supporter
of four sterigmata, and each sterigma of a spore.[D] A closer
examination of the hymenium will reveal the fact that the basidia are
accompanied by other bodies, often larger, but without sterigmata or
spores; these have been termed _cystidia_, and their structure and
functions have been the subject of much controversy.[E] Both kinds of
bodies are produced on the hymenium of most, if not all, the
Agaricini.

[Illustration: FIG. 2.--Section of Common Mushroom.]

[Illustration: FIG. 3.--_a._ Sterile cells. _b._ Basidia. _c._ Cystidium.
From _Gomphidius_ (de Seynes).]

The basidia are usually expanded upwards, so as to have more or less
of a clavate form, surmounted by four slender points, or tubular
processes, each supporting a spore; the contents of these cells are
granular, mixed apparently with oleaginous particles, which
communicate through the slender tubes of the spicules with the
interior of the spores. Corda states that, although only one spore is
produced at a time on each sporophore, when this falls away others are
produced in succession for a limited period. As the spores approach
maturity, the connection between their contents and the contents of
the basidia diminishes and ultimately ceases. When the basidium which
bears mature spores is still well charged with granular matter, it may
be presumed that the production of a second or third series of spores
is quite possible. Basidia exhausted entirely of their contents, and
which have become quite hyaline, may often be observed.

The cystidia are usually larger than the basidia, varying in size and
form in different species. They present the appearance of large
sterile cells, attenuated upwards, sometimes into a slender neck.
Corda was of opinion that these were male organs, and gave them the
name of _pollinaires_. Hoffmann has also described[F] both these
organs under the names of _pollinaria_ and _spermatia_, but does not
appear to recognize in them the sexual elements which those names
would indicate; whilst de Seynes suggests that the cystidia are only
organs returned to vegetative functions by a sort of hypertrophy of
the basidia.[G] This view seems to be supported by the fact that, in
the section _Pluteus_ and some others, the cystidia are surmounted by
short horns resembling sterigmata. Hoffmann has also indicated[H] the
passage of cystidia into basidia. The evidence seems to be in favour
of regarding the cystidia as barren conditions of basidia. There are
to be found upon the hymenium of Agarics a third kind of elongated
cells, called by Corda[I] basilary cells, and by Hoffmann "sterile
cells," which are either equal in size or smaller than the basidia,
with which also their structure agrees, excepting in the development
of spicules. These are the "proper cells of the hymenium" of Léveillé,
and are simply the terminal cells of the gill structure--cells which,
under vigorous conditions, might be developed into basidia, but which
are commonly arrested in their development. As suggested by de Seynes,
the hymenium seems to be reduced to great simplicity, "one sole and
self-same organ is the basis of it; according as it experiences an
arrest of development, as it grows and fructifies, or as it becomes
hypertrophied, it gives us a paraphyse, a basidium, or a cystidium--in
other terms, atrophied basidium, normal basidium and hypertrophied
basidium; these are the three elements which form the hymenium."[J]

The only reproductive organs hitherto demonstrated in Agarics are the
spores, or, as sometimes called, from their method of production,
_basidiospores_.[K] These are at first colourless, but afterwards
acquire the colour peculiar to the species. In size and form they are,
within certain limits, exceedingly variable, although form and size
are tolerably constant in the same species. At first all are globose;
as they mature, the majority are ovoid or elliptic; some are fusiform,
with regularly attenuated extremities. In _Hygrophorus_ they are
rather irregular, reniform, or compressed in the middle. Sometimes the
external surface is rough with more or less projecting warts. Some
mycologists are of opinion that the covering of the spore is double,
consisting of an _exospore_ and an _endospore_, the latter being very
fine and delicate. In other orders the double coating of the spore has
been demonstrated. When the spore is coloured, the external membrane
alone appears to possess colour, the endospore being constantly
hyaline. It may be added here, that in this order the spore is simple
and unicellular. In _Lactarius_ and _Russula_ the trama, or inner
substance, is vesicular. True latex vessels occur occasionally in
_Agaricus_, though not filled with milk as in _Lactarius_.

[Illustration: FIG. 4.--_Polyporus giganteus_ (reduced).]

POLYPOREI.--In this order the gill plates are replaced by tubes or
pores, the interior of which is lined by the hymenium; indications
of this structure having already been exhibited in some of the
lower _Agaricini._ In many cases the stem is suppressed. The
substance is fleshy in _Boletus_, but in _Polyporus_ the greater
number of species are leathery or corky, and more persistent. The
basidia, spicules, and quaternate spores agree with those of
_Agaricini_.[L] In fact there are no features of importance which
relate to the hymenium in any order of _Hymenomycetes_ (the
_Tremellini_ excepted) differing from the same organ in _Agaricini_,
unless it be the absence of _cystidia_.

[Illustration: FIG. 5.--_Hydnum repandum._]

HYDNEI.--Instead of pores, in this order the hymenium is spread over
the surface of spines, prickles, or warts.[M]

AURICULARINI.--The hymenium is more or less even, and in--

CLAVARIEI the whole fungus is club-shaped, or more or less intricately
branched, with the hymenium covering the outer surface.

[Illustration: FIG. 6.--_Calocera viscosa._]

[Illustration: FIG. 7.--_Tremella mesenterica._]

TREMELLINI.--In this order we have a great departure from the
character of the substance, external appearance, and internal
structure of the other orders in this family. Here we have a
gelatinous substance, and the form is lobed, folded, convolute, often
resembling the brain of some animal. The internal structure has been
specially illustrated by M. Tulasne,[N] through the common species,
_Tremella mesenterica_. This latter is of a fine golden yellow colour,
and rather large size. It is uniformly composed throughout of a
colourless mucilage, with no appreciable texture, in which are
distributed very fine, diversely branched and anastomosing filaments.
Towards the surface, the ultimate branches of this filamentous network
give birth, both at their summits and laterally, to globular cells,
which acquire a comparatively large size. These cells are filled with
a protoplasm, to which the plant owes its orange colour. When they
have attained their normal dimensions, they elongate at the summit
into two, three, or four distinct, thick, obtuse tubes, into which the
protoplasm gradually passes. The development of these tubes is unequal
and not simultaneous, so that one will often attain its full
dimensions, equal, perhaps, to three or four times the diameter of the
generative cell, whilst the others are only just appearing. By
degrees, as each tube attains its full size, it is attenuated into a
fine point, the extremity of which swells into a spheroidal cell,
which ultimately becomes a spore. Sometimes these tubes, or spicules,
send out one or two lateral branches, each terminated by a spore.
These spores (about ·006 to ·008 _mm._ diameter) are smooth, and
deposit themselves, like a fine white dust, on the surface of the
_Tremella_ and on its matrix. M. Léveillé[O] was of opinion that the
basidia of the Tremellini were monosporous, whilst M. Tulasne has
demonstrated that they are habitually tetrasporous, as in other of the
Hymenomycetes. Although agreeing in this, they differ in other
features, especially in the globose form of the basidia, mode of
production of the spicules, and, finally, the division of the basidia
into two, three, or four cells by septa which cut each other in their
axis. This division precedes the growth of the spicules. It is not
rare to see these cells, formed at the expense of an unilocular
basidium, become partly isolated from each other; in certain cases
they seem to have separated very early, they then become larger than
usual, and are grouped on the same filament so as to represent a kind
of buds. This phenomenon usually takes place below the level of the
fertile cells, at a certain depth in the mucous tissue of the
_Tremella_.

Besides the reproductive system here described, Tulasne also made
known the existence of a series of filaments which produce spermatia.
These filaments are often scattered and confused with those which
produce the basidia, and not distinguishable from them in size or any
other apparent characteristic, except the manner in which their
extremities are branched in order to produce the spermatia. At other
times the spermatia-bearing surface covers exclusively certain
portions of the fungus, especially the inferior lobes, imparting
thereto a very bright orange colour, which is communicated by the
layer of spermatia, unmixed with spores. These spots retain their
bright colour, while the remainder of the plant becomes pale, or
covered with a white dust. The spermatia are very small, spherical,
and smooth, scarcely equalling ·002 _mm._ They are sessile, sometimes
solitary, sometimes three or four together, on the slightly swollen
extremities of certain filaments of the weft of the fungus.[P] Tulasne
found it impossible to make these corpuscles germinate, and in all
essential particulars they agreed with the spermatia found in
ascomycetous fungi.

In the genus _Dacrymyces_, the same observer found the structure to
have great affinity with that of _Tremella_. The spores in the species
examined were of a different form, being oblong, very obtuse, slightly
curved (·013 - ·019 × ·004 - ·006 _mm._), at first unilocular, but
afterwards triseptate. The basidia are cylindrical or clavate, filled
with coloured granular matter; each of these bifurcates at the summit,
and gradually elongates into two very open branches, which are
attenuated above, and ultimately each is crowned by a spore. There are
to be found also in the species of this genus globose bodies,
designated "sporidioles" by M. Léveillé, which Tulasne took
considerable care to trace to their source. He thus accounts for
them:--Each of the cells of the spore emits exteriorly one or several
of these corpuscles, supported on very short and very slender
pedicels, which remain after the corpuscles are detached from them,
new corpuscles succeeding the first as long as there remains any
plastic matter within the spore. The pedicels are not all on the same
plane; they are often implanted all on the same, and oftenest on the
convex side of the reproductive body. These corpuscles, though placed
under the most favourable conditions, never gave the least sign of
vegetation, and Tulasne concludes that they are spermatia, analogous
to those produced in _Tremella_. The spores which produce spermatia
are not at all apt to germinate, whilst those which did not produce
spermatia germinated freely. Hence it would appear that, although all
spores seem to be perfectly identical, they have not all the same
function. The same observer detected also amongst specimens of the
_Dacrymyces_ some of a darker and reddish tint, always bare of spores
or spermatia on the surface, and these presented a somewhat different
structure. Where the tissue had turned red it was sterile, the
constituent filaments, ordinarily colourless, and almost empty of
solid matter, were filled with a highly-coloured protoplasm; they were
of less tenuity, more irregularly thick, and instead of only rarely
presenting partitions, and remaining continuous, as in other parts of
the plant, were parcelled out into an infinity of straight or curved
pieces, angular and of irregular form, especially towards the surface
of the fungus, where they compose a sort of pulp, varying in cohesion
according to the dry or moist condition of the atmosphere. All parts
of these reddish individuals seemed more or less infected with this
disintegration, the basidia divided by transverse diaphragms into
several cylindrical or oblong pieces, which finally become free.
Transitional conditions were also observed in mixed individuals. This
sterile condition is called by Tulasne "gemmiparous," and he believes
that it has ere now given origin to one or more spurious species, and
misled mycologists as to the real structure of perfect and fruitful
_Dacrymyces_.

PHALLOIDEI.--In this order the hymenium is at first enclosed within a
sort of peridium or universal volva, maintaining a somewhat globose or
egg-shape. This envelope consists of an outer and inner coat of
somewhat similar texture, and an intermediate gelatinous layer, often
of considerable thickness. When a section is made of the fungus,
whilst still enclosed in the volva, the hymenium is found to present
numerous cavities, in which basidia are developed, each surmounted by
spicules (four to six) bearing oval or oblong spores.[Q] It is very
difficult to observe the structure of the hymenium in this order, on
account of its deliquescent nature. As the hymenium approaches
maturity, the volva is ruptured, and the plant rapidly enlarges. In
_Phallus_, a long erect cellular stem bears the cap, over which the
hymenium is spread, and this expands enormously after escaping the
restraint of the volva. Soon after exposure, the hymenium deliquesces
into a dark mucilage, coloured by the minute spores, which drips from
the pileus, often diffusing a most loathsome odour for a considerable
distance. In _Clathrus_, the receptacle forms a kind of network. In
_Aseröe_, the pileus is beautifully stellate. In many the attractive
forms would be considered objects of beauty, were it not for their
deliquescence, and often foetid odour.[R]

[Illustration: FIG. 8.--Basidia and spores of _Phallus_.]

PODAXINEI.--This is a small but very curious group of fungi, in which
the peridium resembles a volva, which is more or less confluent with
the surface of the pileus. They assume hymenomycetal forms, some of
them looking like Agarics, Boleti, or species of _Hydnum_, with
deformed gills, pores, or spines; in _Montagnites_, in fact, the gill
structure is very distinct. The spores are borne in definite clusters
on short pedicels in such of the genera as have been examined.[S]

HYPOGÆI.--These are subterranean puff-balls, in which sometimes a
distinct peridium is present; but in most cases it consists entirely
of an external series of cells, continuous with the internal
structure, and cannot be correctly estimated as a peridium. The
hymenium is sinuous and convolute, bearing basidia with sterigmata and
spores in the cavities. Sometimes the cavities are traversed by
threads, as in the _Myxogastres_. The spores are in many instances
beautifully echinulate, sometimes globose, at others elongated, and
produced in such numbers as to lead to the belief that their
development is successive on the spicules. When fully matured, the
peridia are filled with a dusty mass of spores, so that it is scarcely
possible in this condition to gain any notion of the structure. This
is, indeed, the case with nearly all _Gasteromycetes_. The hypogæous
fungi are curiously connected with _Phalloidei_ by the genus
_Hysterangium_.

[Illustration: FIG. 9.--Basidia and spores of _Lycoperdon_.]

TRICHOGASTRES.[T]--In their early stages the species contained in
this group are not gelatinous, as in the _Myxogastres_, but are
rather fleshy and firm. Very little has been added to our knowledge
of structure in this group since 1839 and 1842, when one of us
wrote to the following effect:--If a young plant of _Lycoperdon
coelatum_ or _L. gemmatum_ be cut through and examined with a common
pocket lens, it will be found to consist of a fleshy mass,
perforated in every direction with minute elongated, reticulated,
anastomosing, labyrinthiform cavities. The resemblance of these to the
tubes of _Boleti_ in an early stage of growth, first led me to
suspect that there must be some very close connection between them.
If a very thin slice now be taken, while the mass is yet firm, and
before there is the slightest indication of a change of colour, the
outer stratum of the walls of these cavities is found to consist of
pellucid obtuse cells, placed parallel to each other like the pile
of velvet, exactly as in the young hymenium of an Agaric or
Boletus. Occasionally one or two filaments cross from one wall to
another, and once I have seen these anastomose. At a more advanced
stage of growth, four little spicules are developed at the tips of
the sporophores, all of which, as far as I have been able to observe,
are fertile and of equal height, and on each of these spicules a
globose spore is seated. It is clear that we have here a structure
identical with that of the true Hymenomycetes, a circumstance which
accords well with the fleshy habit and mode of growth. There is some
difficulty in ascertaining the exact structure of the species just
noticed, as the fruit-bearing cells, or sporophores, are very
small, and when the spicules are developed the substance becomes so
flaccid that it is difficult to cut a proper slice, even with the
sharpest lancet. I have, however, satisfied myself as to the true
structure by repeated observations. But should any difficulty arise
in verifying it in the species in question, there will be none in
doing so in _Lycoperdon giganteum_. In this species the fructifying
mass consists of the same sinuous cavities, which are, however,
smaller, so that the substance is more compact, and I have not seen
them traversed by any filaments. In an early stage of growth, the
surface of the hymenium, that is of the walls of the cavities,
consists of short threads composed of two or three articulations,
which are slightly constricted at the joints, from which, especially
from the last, spring short branchlets, often consisting of a
single cell. Sometimes two or more branchlets spring from the same
point. Occasionally the threads are constricted without any
dissepiments, the terminal articulations are obtuse, and soon swell
very much, so as greatly to exceed in diameter those on which they
are seated. When arrived at their full growth, they are somewhat
obovate, and produce four spicules, which at length are surmounted
each with a globose spore. When the spores are fully developed, the
sporophores wither, and if a solution of iodine be applied, which
changes the spores to a rich brown, they will be seen still adhering
by their spicules to the faded sporophores. The spores soon become
free, but the spicule often still adheres to them; but they are not
attached to the intermingled filaments. In _Bovista plumbea_, the
spores have very long peduncles.[U] As in the _Hymenomycetes_, the
prevailing type of reproductive organs consisted of quaternary
spores borne on spicules; so in _Gasteromycetes_, the prevailing
type, in so far as it is yet known, is very similar, in some cases
nearly identical, consisting of a definite number of minute spores
borne on spicules seated on basidia. In a very large number of
genera, the minute structure and development of the fructification
(beyond the mature spores) is almost unknown, but from analogy it
may be concluded that a method prevails in a large group like the
_Myxogastres_ which does not differ in essential particulars from that
which is known to exist in other groups. The difficulties in the way
of studying the development of the spores in this are far greater
than in the previous order.

[Illustration: FIG. 10.--_a._ Threads of _Trichia_. _b._ Portion further
magnified, with spores. _c._ Portion of spinulose thread.]

MYXOGASTRES.--At one time that celebrated mycologist, Professor De
Bary, seemed disposed to exclude this group from the vegetable kingdom
altogether, and relegate them to a companionship with amoeboid forms.
But in more recent works he seems to have reconsidered, and almost, if
not entirely, abandoned, that disposition. These fungi, mostly minute,
are characterized in their early stages by their gelatinous nature.
The substance of which they are then composed bears considerable
resemblance to sarcode, and, did they never change from this, there
might be some excuse for doubting as to their vegetable nature; but as
the species proceed towards maturity they lose their mucilaginous
texture, and become a mass of spores, intermixed with threads,
surrounded by a cellular peridium. Take, for instance, the genus
_Trichia_, and we have in the matured specimens a somewhat globose
peridium, not larger than a mustard seed, and sometimes nearly of the
same colour; this ultimately ruptures and exposes a mass of minute
yellow spherical spores, intermixed with threads of the same
colour.[V] These threads, when highly magnified, exhibit in themselves
a spiral arrangement, which has been the basis of some controversy,
and in some species these threads are externally spinulose. The chief
controversy on these threads has been whether the spiral markings are
external or internal, whether caused by twisting of the thread or by
the presence of an external or internal fibre. The spiral appearance
has never been called in question, only the structure from whence it
arises, and this, like the striæ of diatoms, is very much an open
question. Mr. Currey held that the spiral appearance may be accounted
for by supposing the existence of an accurate elevation in the wall of
the cell, following a spiral direction from one end of the thread to
the other. This supposition would, he thinks, accord well with the
optical appearances, and it would account exactly for the undulations
of outline to which he alludes. He states that he had in his
possession a thread of _Trichia chrysosperma_, in which the spiral
appearance was so manifestly caused by an elevation of this nature, in
which it is so clear that no internal spiral fibre exists, that he did
not think there could be a doubt in the mind of any person carefully
examining it with a power of 500 diameters that the cause of the
spiral appearance was not a spiral fibre. In _Arcyria_, threads of a
different kind are present; they mostly branch and anastomose, and are
externally furnished with prominent warts or spines, which Mr.
Currey[W] holds are also arranged in a spiral manner around the
threads. In other Myxogastres, threads are also present without any
appreciable spiral markings or spines. In the mature condition of
these fungi, they so clearly resemble, and have such close affinities
with, the Trichogastres that one is led almost to doubt whether it was
not on hasty grounds, without due examination or consideration, that
proposals were made to remove them from the society of their kindred.

[Illustration: FIG. 11.--_Arcyria incarnata_, with portion of threads and
spore, magnified.]

Very little is known of the development of the spores in this group;
in the early stages the whole substance is so pulpy, and in the latter
so dusty, whilst the transition from one to the other is so rapid,
that the relation between the spores and threads, and their mode of
attachment, has never been definitely made out. It has been supposed
that the spinulose projections from the capillitium in some species
are the remains of pedicels from which, the spores have fallen, but
there is no evidence beyond this supposition in its favour, whilst on
the other hand, in _Stemonitis_, for instance, there is a profuse
interlacing capillitium, and no spines have been detected. In order to
strengthen the supposition, spines should be more commonly present.
The threads, or capillitium, form a beautiful reticulated network in
_Stemonitis_, _Cribraria_, _Diachæa_, _Dictydium_, &c. In _Spumaria_,
_Reticularia_, _Lycogala_, &c., they are almost obsolete.[X] In no
group is the examination of the development of structure more
difficult, for the reasons already alleged, than in the Myxogastres.

[Illustration: FIG. 12.--_Diachæa elegans._]

[Illustration: FIG. 13.--_Cyathus vernicosus._]

NIDULARIACEI.--This small group departs in some important particulars
from the general type of structure present in the rest of the
Gasteromycetes.[Y] The plants here included may be described under
three parts, the mycelium, the peridium, and the sporangia. The
mycelium is often plentiful, stout, rigid, interlacing, and coloured,
running over the surface of the soil, or amongst the vegetable débris
on which the fungi establish themselves. The peridia are seated upon
this mycelium, and in most instances are at length open above, taking
the form of cups, or beakers. These organs consist of three strata of
tissue varying in structure, the external being fibrous, and sometimes
hairy, the interior cellular and delicate, the intermediate thick and
at length tough, coriaceous, and resistant. When first formed, the
peridia are spherical, they then elongate and expand, the mouth being
for some time closed by a veil, or diaphragm, which ultimately
disappears. Within the cups lentil-shaped bodies are attached to the
base and sides by elastic cords. These are the sporangia. Each of
these has a complicated structure; externally there is a filamentous
tunic, composed of interlaced fibres, sometimes called the peridiole;
beneath this is the cortex, of compact homogenous structure, then
follows a cellular thicker stratum, bearing, towards the centre of the
sporangia, delicate branched threads, or sporophores, on which, at
their extremities, the ovate spores are generated, sometimes in pairs,
but normally, it would seem that they are quaternary on spicules, the
threads being true basidia. The whole structure is exceedingly
interesting and peculiar, and may be studied in detail in Tulasne's
memoir on this group.

SPHÆRONEMEI.--In this very large and, within certain limits, variable
order, there is but little of interest as regards structure, which is
not better illustrated elsewhere; as, for instance, some sort of
perithecium is always present, but this can be better studied in the
_Sphæriacei_. The spores are mostly very minute, borne on delicate
sporophores, which originate from the inner surface of the perithecia,
but the majority of so-called species are undoubtedly conditions of
sphæriaceous fungi, either spermatogonia or pycnidia, and are of much
more interest when studied in connection with the higher forms to
which they belong.[Z] Probably the number of complete and autonomous
species are very few.

[Illustration: FIG. 14.--_Cyathus._ _a._ Sporangium. _b._ Section. _c._
Sporophore. _d._ Spores.]

MELANCONIEI.--Here, again, are associated together a great number of
what formerly were considered good species of fungi, but which are
now known to be but conditions of other forms. One great point of
distinction between these and the preceding is the absence of any
true perithecium, the spores being produced in a kind of spurious
receptacle, or from a sort of stroma. The spores are, as a rule,
larger and much more attractive than in _Sphæronemei_, and, in
some instances, are either very fine, or very curious. Under this
head we may mention the multiseptate spores of _Coryneum_; the
tri-radiate spores of _Asterosporium_; the curious crested spores of
_Pestalozzia_; the doubly crested spores of _Dilophospora_; and the
scarcely less singular gelatinous coated spores of _Cheirospora_.
In all cases the fructification is abundant, and the spores frequently
ooze out in tendrils, or form a black mass above the spurious
receptacle from which they issue.[a]

[Illustration: FIG. 15.--_Asterosporium Hoffmanni._]

TORULACEI.--In this order there seems at first to be a considerable
resemblance to the _Dematiei_, except that the threads are almost
obsolete, and the plant is reduced to chains of spores, without trace
of perithecium, investing cuticle, or definite stroma. Sometimes the
spores are simple, in other cases septate, and in _Sporochisma_ are at
first produced in an investing cell. In most cases simple threads at
length become septate, and are ultimately differentiated into spores,
which separate at the joints when fully mature.

[Illustration: FIG. 16.--Barren Cysts and Pseudospores of _Lecythea_.]

[Illustration: FIG. 17.--_Coleosporium Tussilaginis_, Lev.]

[Illustration: FIG. 18.--_Melampsora salicina._]

CÆOMACEI.--Of far greater interest are the Coniomycetous parasites
on living plants. The present order includes those in which the
spore[b] is reduced to a single cell; and here we may observe that,
although many of them are now proved to be imperfect in themselves,
and only forms or conditions of other fungals, we shall write of them
here without regard to their duality. These originate, for the most
part, within the tissues of living plants, and are developed outwards
in pustules, which burst through the cuticle. The mycelium penetrates
the intercellular passages, and may sometimes be found in parts
of the plants where the fungus does not develop itself. There is no
proper excipulum or peridium, and the spores spring direct from a
more compacted portion of the mycelium, or from a cushion-like
stroma of small cells. In _Lecythea_, the sub-globose spores are at
first generated at the tips of short pedicels, from which they are
ultimately separated; surrounding these spores arise a series of
barren cells, or cysts, which are considerably larger the true spores,
and colourless, while the spores are of some shade of yellow or
orange.[c] In _Trichobasis_, the spores are of a similar character,
sub-globose, and at first pedicellate; but there are no surrounding
cysts, and the colour is more usually brown, although sometimes
yellow. In _Uredo_, the spores are at first generated singly, within
a mother cell; they are globose, and either yellow or brown, without
any pedicel. In _Coleosporium_, there are two kinds of spores,
those of a pulverulent nature, globose, which are sometimes produced
alone at the commencement of the season, and others which originate
as an elongated cell; this becomes septate, and ultimately separates
at the joints. During the greater part of the year, both kinds of
spores are to be found in the same pustule. In _Melampsora_, the
winter spores are elongated and wedge-shaped, compacted together
closely, and are only matured during winter on dead leaves; the summer
spores are pulverulent and globose, being, in fact, what were until
recently regarded as species of _Lecythea_. In _Cystopus_, the spores
are sub-globose, or somewhat angular, generated in a moniliform
manner, and afterwards separating at the joints. The upper spore is
always the oldest, continuous production of spores going on for some
time at the base of the chain. Under favourable conditions of
moisture, each of these spores, or conidia, as De Bary terms them, is
capable of producing within itself a number of zoospores;[d] these
ultimately burst the vesicle, move about by the aid of vibratile
cilia, and at last settle down to germinate. Besides these, other
reproductive bodies are generated upon the mycelium, within the
tissues of the plant, in the form of globose oogonia, or resting
spores, which, when mature, also enclose great numbers of zoospores.
Similar oogonia are produced amongst the _Mucedines_ in the genus
_Peronospora_, to which De Bary considers _Cystopus_ to be closely
allied. At all events, this is a peculiarity of structure and
development not as yet met with in any other of the _Cæomacei_. In
_Uromyces_ is the nearest approach to the _Pucciniæi_; in fact, it is
_Puccinia_ reduced to a single cell. The form of spore is usually
more angular and irregular than in _Trichobasis_, and the pedicel is
permanent. It may be remarked here, that of the foregoing genera,
many of the species are not autonomous that have hitherto been
included amongst them. This is especially true of _Lecythea_,
_Trichobasis_, and, as it now appears, of _Uromyces_.[e]

[Illustration: FIG. 19.--_Cystopus candidus._]

[Illustration: FIG. 20.--_Xenodochus carbonarius._]

[Illustration: FIG. 21.--_Phragmidium bulbosum._]

PUCCINIÆI.--This group differs from the foregoing chiefly in having
septate spores. The pustules, or sori, break through the cuticle in a
similar manner, and here also no true peridium is present. In
_Xenodochus_, the highest development of joints is reached, each
spore being composed of an indefinite number, from ten to twenty
cells. With it is associated an unicellular yellow Uredine, of which
it is a condition. Probably, in every species of the _Pucciniæi_, it
may hereafter be proved, as it is now suspected, that an unicellular
Uredine precedes or is associated with it, forming a condition, or
secondary form of fruit of that species. Many instances of that kind
have already been traced by De Bary,[f] Tulasne, and others, and some
have been a little too rashly surmised by their followers. In
_Phragmidium_, the pedicel is much more elongated than in _Xenodochus_,
and the spore is shorter, with fewer and a more definite number of
cells for each species; Mr. Currey is of opinion that each cell of
the spore in _Phragmidium_ has an inner globose cell, which he caused
to escape by rupture of the outer cell wall as a sphæroid nucleus,[g]
leading to the inference that each cell has its own individual power
of germination and reproduction. In _Triphragmium_, there are three
cells for each spore, two being placed side by side, and one
superimposed. In one species, however, _Triphragmium deglubens_
(North American), the cells are arranged as in _Phragmidium_, so that
this represents really a tricellular _Phragmidium_, linking the present
with the latter genus. In _Puccinia_ the number of species is by far the
most numerous; in this genus the spores are uniseptate, and, as in
all the _Pucciniæi_, the peduncles are permanent. There is great
variability in the compactness of the spores in the sori, or pulvinules.
In some species, the sori are so pulverulent that the spores are as
readily dispersed as in the Uredines, in others they are so compact as
to be separated from each other with great difficulty. As might be
anticipated, this has considerable effect on the contour of the spores,
which in pulverulent species are shorter, broader, and more ovate than
in the compact species. If a section of one of the more compact sori be
made, it will be seen that the majority of the spores are side by side,
nearly at the same level, their apices forming the external surface
of the sori, but it will not be unusual to observe smaller and
younger spores pushing up from the hymenial cells, between the
peduncles of the elder spores, leading to the inference that there is a
succession of spores produced in the same pulvinule. In _Podisoma_, a
rather anomalous genus, the septate spores are immersed in a
gelatinous stratum, and some authors have imagined that they have an
affinity with the Tremellini, but this affinity is more apparent than
real. The phenomena of germination, and their relations to _Roestelia_,
if substantiated, establish their claim to a position amongst the
_Pucciniæi_.[h] It seems to us that _Gymnosporangium_ does not differ
generically from _Podisoma_. In a recently-characterized species,
_Podisoma Ellisii_, the spores are bi-triseptate. This is, moreover,
peculiar from the great deficiency in the gelatinous element. In
another North American species, called _Gymnosporangium biseptatum_,
Ellis, which is distinctly gelatinous, there are similar biseptate
spores, but they are considerably broader and more obtuse. In other
described species they are uniseptate.

[Illustration: FIG. 22.--Pseudospores of _Puccinia_.]

USTILAGINEI.--These fungi are now usually treated as distinct from the
_Cæomacei_, to which they are closely related.[i] They are also
parasitic on growing plants, but the spores are usually black or
sooty, and never yellow or orange; on an average much smaller than in
the _Cæomacei_. In _Tilletia_, the spores are spherical and
reticulated, mixed with delicate threads, from whence they spring. In
the best known species, _Tilletia caries_, they constitute the "bunt"
of wheat. The peculiarities of germination will be alluded to
hereafter. In _Ustilago_, the minute sooty spores are developed either
on delicate threads or in compacted cells, arising first from a sort
of semi-gelatinous, grumous stroma. It is very difficult to detect any
threads associated with the spores. The species attack the flowers and
anthers of composite and polygonaceous plants, the leaves, culms, and
germen of grasses, &c., and are popularly known as "smuts." In
_Urocystis_ and _Thecaphora_, the spores are united together into
sub-globose bodies, forming a kind of compound spore. In some species
of _Urocystis_, the union which subsists between them is comparatively
slight. In _Thecaphora_, on the contrary, the complex spore, or
agglomeration of spores, is compact, being at first apparently
enclosed in a delicate cyst. In _Tuburcinia_, the minute cells are
compacted into a hollow sphere, having lacunæ communicating with the
interior, and often exhibiting the remains of a pedicel.

[Illustration: FIG. 23.--_Thecaphora hyalina._]

[Illustration: FIG. 24.--_Æcidium Berberidis._]

ÆCIDIACEI.--This group differs from the foregoing three groups
prominently in the presence of a cellular peridium, which encloses
the spores; hence some mycologists have not hesitated to propose
their association with the Gasteromycetes, although every other
feature in their structure seems to indicate a close affinity
with the _Cæomacei_. The pretty cups in the genus _Æcidium_ are
sometimes scattered and sometimes collected in clusters, either with
spermogonia in the centre or on the opposite surface. The cups
are usually white, composed of regularly arranged bordered cells
at length bursting at the apex, with the margins turned back and
split into radiating teeth. The spores are commonly of a bright
orange or golden yellow, sometimes white or brownish, and are
produced in chains, or moniliform strings, slightly attached to
each other,[j] and breaking off at the summit at the same time that
they continue to be produced at the base, so that for some time
there is a successive production of spores. The spermogonia are
not always readily detected, as they are much smaller than the
peridia, and sometimes precede them. The spermatia are expelled
from the lacerated and fringed apices, and are very minute and
colourless. In _Roestelia_ the peridia are large, growing in
company, and splitting longitudinally in many cases, or by a
lacerated mouth. In most instances, the spores are brownish, but
in a splendid species from North America (_Roestelia aurantiaca_,
Peck), recently characterized, they are of a bright orange. If
Oersted is correct in his observations, which await confirmation,
these species are all related to species of _Podisoma_ as a
secondary form of fruit.[k] In the _Roestelia_ of the pear-tree, as
well as in that of the mountain ash, the spermogonia will be found
either in separate tufts on discoloured spots, or associated with
the _Roestelia_, In _Peridermium_ there is very little structural
difference from _Roestelia_, and the species are all found on
coniferous trees. In _Endophyllum_, the peridia are immersed in the
succulent substance of the matrix; whilst in _Graphiola_, there is
a tougher and withal double peridium, the inner of which forms a
tuft of erect threads resembling a small brush.[l]

[Illustration: FIG. 25.--_Helminthosporium molle._]

HYPHOMYCETES.--The predominant feature in the structure of this order
has already been intimated to consist in the development of the
vegetative system under the form of simple or branched threads, on
which the fruit is generated. The common name of mould is applied to
them perhaps more generally than to other groups, although the term is
too vague, and has been too vaguely applied to be of much service in
giving an idea of the characteristics of this order. Leaving the
smaller groups, and confining ourselves to the _Dematiei_ and the
_Mucedines_, we shall obtain some notion of the prevalent structure.
In the former the threads are more or less carbonized, in the latter
nearly colourless. One of the largest genera in _Dematiei_ is
_Helminthosporium_. It appears on decaying herbaceous plants, and on
old wood, forming effused black velvety patches. The mycelium, of
coloured jointed threads, overlays and penetrates the matrix; from
this arise erect, rigid, and usually jointed threads, of a dark brown,
nearly black colour at the base, but paler towards the apex. In most
cases these threads have an externally cortical layer, which imparts
rigidity; usually from the apex, but sometimes laterally, the spores
are produced. Although sometimes colourless, these are most commonly
of some shade of brown, more or less elongated, and divided
transversely by few or many septa. In _Helminthosporium Smithii_, the
spores much exceed the dimensions of the threads;[m] in other species
they are smaller. In _Dendryphium_, the threads and spores are very
similar, except that the threads are branched at their apex, and the
spores are often produced one at the end of another in a short
chain.[n] In _Septosporium_ again, the threads and spores are similar,
but the spores are pedicellate, and attached at or near the base;
whilst in _Acrothecium_, with similar threads and spores, the latter
are clustered together at the apex of the threads. In _Triposporium_,
the threads are similar, but the spores are tri-radiate; and in
_Helicoma_, the spores are twisted spirally. Thus, we might pass
through all the genera to illustrate this chief feature of coloured,
septate, rather rigid, and mostly erect threads, bearing at some point
spores, which in most instances are elongated, coloured, and septate.

[Illustration: FIG. 26.--_Acrothecium simplex._]

[Illustration: FIG. 27.--_Peronospora Arenariæ._]

MUCEDINES.--Here, on the other hand, the threads, if coloured at all,
are still delicate, more flexuous, with much thinner walls, and never
invested with an external cortical layer. One of the most important
and highly developed genera is _Peronospora_, the members of which are
parasitic upon and destructive of living vegetables. It is to this
genus that the mould of the too famous potato disease belongs.
Professor De Bary has done more than any other mycologist in the
investigation and elucidation of this genus; and his monograph is a
masterpiece in its way.[o] He was, however, preceded by Mr. Berkeley,
and more especially by Dr. Montagne, by many years in elucidation of
the structure of the flocci and conidia in a number of species.[p] In
this genus, there is a delicate mycelium, which penetrates the
intercellular passages of living plants, giving rise to erect branched
threads, which bear at the tips of their ultimate ramuli, sub-globose,
ovate, or elliptic spores, or, as De Bary terms them--conidia. Deeply
seated on the mycelium, within the substance of the foster plant,
other reproductive bodies, called oogonia, originate. These are
spherical, more or less warted and brownish, the contents of which
become differentiated into vivacious zoospores, capable, when
expelled, of moving in water by the aid of vibratile cilia. A similar
structure has already been indicated in _Cystopus_, otherwise it is
rare in fungi, if the _Saprolegniei_ be excluded. In _Botrytis_ and in
_Polyactis_, the flocci and spores are similar, but the branches of
the threads are shorter and more compact, and the septa are more
common and numerous; the oogonia also are absent. De Bary has selected
_Polyactis cinerea_, as it occurs on dead vine leaves, to illustrate
his views of the dualism which he believes himself to have discovered
in this species. "It spreads its mycelium in the tissue which is
becoming brown," he writes, "and this shows at first essentially the
same construction and growth as that of the mycelium filaments of
_Aspergillus_." On the mycelium soon appear, besides those which are
spread over the tissue of the leaves, strong, thick, mostly
fasciculate branches, which stand close to one another, breaking forth
from the leaf and rising up perpendicularly, the conidia-bearers. They
grow about 1 _mm._ long, divide themselves, by successively rising
partitions, into some prominent cylindrical linked cells, and then
their growth is ended, and the upper cell produces near its point
three to six branches almost standing rectangularly. Of these the
under ones are the longest, and they again shoot forth from under
their ends one or more still shorter little branches. The nearer they
are to the top, the shorter are the branches, and less divided; the
upper ones are quite branchless, and their length scarcely exceeds the
breadth of the principal stem. Thus a system of branches appears, upon
which, on a small scale, a bunch of grapes is represented. All the
twigs soon end their growth; they all separate their inner space from
the principal stem, by means of a cross partition placed close to it.
All the ends, and also that of the principal stem, swell about the
same time something like a bladder, and on the upper free half of each
swelling appear again, simultaneously, several fine protuberances,
close together, which quickly grow to little oval bladders filled with
protoplasm, and resting on their bearers with a sub-sessile,
pedicellate, narrow basis, and which at length separate themselves
through a partition as in _Aspergillus_. The detached cells are the
conidia of our fungus; only one is formed on each stalk. When the
formation is completed in the whole of the panicle, the little
branches which compose it are deprived of their protoplasm in favour
of the conidia; it is the same with the under end of the principal
stem, the limits of which are marked by a cross partition. The
delicate wall of these parts shrinks up until it is unrecognizable;
all the conidia of the panicle approach one another to form an
irregular grape-like bunch, which rests loosely on the bearer, and
from which it easily falls away as dust. If they be brought into water
they fall off immediately; only the empty, shrivelled, delicate skins
are to be found on the branch which bore them, and the places on which
they are fixed to the principal stem clearly appear as round
circumscribed hilums, generally rather arched towards the exterior.
The development of the main stem is not ended here. It remains solid
and filled with protoplasm as far as the portion which forms the end
through its conidia. Its end, which is to be found among these pieces,
becomes pointed after the ripening of the first panicle, pushes the
end of the shrivelled member on one side, and grows to the same length
as the height of one or two panicles, and then remains still, to form
a second panicle similar to the first. This is later equally
perfoliated as the first, then a third follows, and thus a large
number of panicles are produced after and over one another on the same
stem. In perfect specimens, every perfoliated panicle hangs loosely to
its original place on the surface of the stem, until by shaking or the
access of water to it, it falls immediately into the single conidia,
or the remains of branches, and the already-mentioned oval hilums are
left behind. Naturally, the stem becomes longer by every perfoliation;
in luxuriant specimens the length can reach that of some lines. Its
partition is already, by the ripening of the first panicle from the
beginning of its foundation, strong and brown; it is only colourless
at the end which is extending, and in all new formations. During all
these changes the filament remains either unbranched, except as
regards the transient panicles, or it sends out here and there, at the
perfoliated spots, especially from the lower ones, one or two strong
branches, standing opposite one another and resembling the principal
stem.

[Illustration: FIG. 28.--_Polyactis cinerea._ _a._ Apex of hypha.]

The mycelium, which grows so exuberantly in the leaf, often brings
forth many other productions, which are called _sclerotia_, and are,
according to their nature, a thick bulbous tissue of mycelium
filaments. Their formation begins with the profuse ramification of the
mycelium threads in some place or other; generally, but not always, in
the veins of the leaf; the intertwining twigs form an uninterrupted
cavity, in which is often enclosed the shrivelling tissue of the leaf.
The whole body swells to a greater thickness than that of the leaf,
and protrudes on the surface like a thickened spot. Its form varies
from circular to fusiform; its size is also very unequal, ranging
between a few lines and about half a millimetre in its largest
diameter. At first it is colourless, but afterwards its outer layers
of cells become round, of a brown or black colour, and it is
surrounded by a black rind, consisting of round cells, which separate
it from the neighbouring tissue. The tissue within the rind remains
colourless; it is an entangled uninterrupted tissue of fungus
filaments, which gradually obtain very solid, hard, cartilaginous
coats. The sclerotium, which ripens as the rind becomes black, loosens
itself easily from the place of its formation, and remains preserved
after the latter is decayed.

[Illustration: FIG. 29.--_Peziza Fuckeliana._ _a._ Natural size. _b._
Section enlarged. _c._ Ascus and sporidia.]

The sclerotia are, here as in many other fungi, biennial organs,
designed to begin a new vegetation after a state of apparent quietude,
and to send forth special fruit-bearers. They may in this respect be
compared to the bulbs and perennial roots of under shrubs. The usual
time for the development of the sclerotia is late in the autumn,
after the fall of the vine leaves. As long as the frost does not set
in, new ones continually spring up, and each one attains to ripeness
in a few days. If frost appears, it can lie dry a whole year, without
losing its power of development. This latter commences when the
sclerotium is brought into contact with damp ground during the usual
temperature of our warmer seasons. If this occur soon, at the latest
some weeks after it is ripe, new vegetation grows very quickly,
generally after a few days; in several parts the colourless filaments
of the inner tissue begin to send out clusters of strong branches,
which, breaking through the black rind, stretch themselves up
perpendicularly towards the surface, separate from one another, and
then take all the characteristics of the conidia-bearers. Many such
clusters can be produced on one sclerotium, so that soon the greater
part of the surface is covered by filamentous conidia-bearers with
their panicles. The colourless tissue of the sclerotium disappears in
the same degree as the conidia-bearers grow, and at last the black
rind remains behind empty and shrivelled. If we bring, after many
months, for the first time, the ripe sclerotium, in damp ground, in
summer or autumn, after it has ripened, the further development takes
place more slowly, and in an essentially different form. It is true
that from the inner tissue numerous filamentous branches shoot forth
at the cost of this growing fascicle, and break through the black
rind, but its filaments remain strongly bound, in an almost parallel
situation, to a cylindrical cord, which for a time lengthens itself
and spreads out its free end to a flat plate-like disc. This is always
formed of strongly united threads, ramifications of the cylindrical
cord. On the free upper surface of the disc, the filaments shoot forth
innumerable branches, which, growing to the same height, thick and
parallel with one another, cover the before-named disc. Some remain
narrow and cylindrical, are very numerous, and produce fine hairs
(paraphyses); others, also very numerous, take the form of club-like
ampulla cells, and each one forms in its interior eight free swimming
oval spores. Those ampulla cells are sporidiiferous asci. After the
spores have become ripe, the free point of the utricle bursts, and the
spores are scattered to a great distance by a mechanism which we will
not here further describe. New ampullas push themselves between those
which are ripening and withering; a disc can, under favourable
circumstances, always form new asci for weeks at a time. The number of
the already described utricle-bearers is different, according to the
size of the sclerotium; smaller specimens usually produce only one,
larger two to four. The size is regulated by that of the sclerotia,
and ranges, in full-grown specimens, between one and more millimetres
for the length of the stalk, and a half to three (seldom more)
millimetres for the breadth of the disc.[q] For some time the conidia
form, belonging to the Mucedines, has been known as _Botrytis cinerea_
(or _Polyactis cinerea_). The compact mycelium, or sclerotium, as an
imperfect fungus, bore the name of _Sclerotium echinatum_, whilst to
the perfect and cup-like form has been given the name of _Peziza
Fuckeliana_. We have reproduced De Bary's life-history of this mould
here, as an illustration of structure in the _Mucedines_, but
hereafter we shall have to write of similar transformations when
treating of polymorphism.

The form of the threads, and the form and disposition of the spores,
vary according to the genera of which this order is composed. In
_Oidium_ the mostly simple threads break up into joints. Many of the
former species are now recognized as conditions of _Erysiphe_. In
_Aspergillus_, the threads are simple and erect, with a globose head,
around which are clustered chains of simple spores. In _Penicillium_,
the lower portion of the threads is simple, but they are shortly
branched at the apex, the branches being terminated by necklaces of
minute spores. In _Dactylium_, the threads are branched, but the
spores are collected in clusters usually, and are moreover septate. In
other genera similar distinctions prevail. These two groups of black
moulds and white moulds are the noblest, and contain the largest
number of genera and species amongst the _Hyphomycetes_. There is,
however, the small group of _Isariacei_, in which the threads are
compacted, and a semblance of such hymenomycetal forms as _Clavaria_
and _Pterula_ is the result, but it is doubtful if this group contains
many autonomous species. In another small group, the _Stilbacei_,
there is a composite character in the head, or receptacle,[r] and in
the stem when the latter is present. Many of these, again, as
_Tubercularia_, _Volutella_, _Fusarium_, &c., contain doubtful
species. In _Sepedoniei_ and _Trichodermacei_, the threads are reduced
to a minimum, and the spores are such a distinctive element that
through these groups the _Hyphomycetes_ are linked with the
_Coniomycetes_. These groups, however, are not of sufficient size or
importance to demand from us, in a work of this character, anything
more than the passing allusion which we have given to them.

[Illustration: FIG. 30.--_Penicillium chartarum_, Cooke.]

We come now to consider the structure in the Sporidiifera, in which
the fructifying corpuscles or germs, whether called spores or
sporidia, are generated within certain privileged cysts, usually in
definite numbers. In systematic works, these are included under two
orders, the _Physomycetes_ and the _Ascomycetes_. The former of these
consists of cyst-bearing moulds, and from their nearest affinity to
the foregoing will occupy the first place.

[Illustration: FIG. 31.--_Mucor mucedo_, with three sporangia. _a._
Portion of frill with sporangiola.]

PHYSOMYCETES include, especially amongst the _Mucorini_, many most
interesting and instructive species for study, which even very lately
have occupied the attention of continental mycologists. Most of these
phenomena are associated more or less with reproduction, and as such
will have to be adverted to again, but there are points in the
structure which can best be alluded to here. Again taking Professor de
Bary's researches as our guide,[s] we will illustrate this by the
common _Mucor mucedo_: If we bring quite fresh horse-dung into a damp
confined atmosphere, for example, under a bell-glass, there appears on
its surface, after a few days, an immense white mildew. Upright strong
filaments of the breadth of a hair raise themselves over the surface,
each of them soon shows at its point a round little head, which
gradually becomes black, and a closer examination shows us that in all
principal points it perfectly agrees with the sporangia of other
species. Each of these white filaments is a sporangia-bearer. They
spring from a mycelium which is spread in the dung, and appear singly
upon it. Certain peculiarities in the form of the sporangium, and the
little long cylindrical spores, which, when examined separately, are
quite flat and colourless, are characteristic of the species. If the
latter be sown in a suitable medium, for example, in a solution of
sugar, they swell, and shoot forth germinating utricles, which quickly
grow to mycelia, which bear sporangia. This is easily produced on the
most various organic bodies, and _Mucor mucedo_ is therefore found
spontaneously on every substratum which is capable of nourishing
mildew, but on the above-named the most perfect and exuberant
specimens are generally to be found. The sporangia-bearers are at
first always branchless and without partitions. After the sporangium
is ripe, cross partitions in irregular order and number often appear
in the inner space, and on the upper surface branches of different
number and size, each of which forms a sporangium at its point. The
sporangia which are formed later are often very similar, but sometimes
very different, to those which first appeared, because their partition
is very thick and does not fall to pieces when it is ripe, but
irregularly breaks off, or remains entire, enclosing the spores, and
at last falls to the ground, when the fungus withers. The cross
partition which separates the sporangia from its bearers is in those
which are first formed (which are always relatively thicker sporangia)
very strongly convex, while those which follow later are often
smaller, and in little weak specimens much less arched, and sometimes
quite straight. After a few days, similar filaments generally show
themselves on the dung between the sporangia-bearers, which appear to
the naked eye to be provided with delicate white frills. Where such an
one is to be found, two to four rectangular expanding little branches
spring up to the same height round the filament. Each of these, after
a short and simple process, branch out into a furcated form; the
furcations being made in such a manner that the ends of the branch at
last so stand together that their surface forms a ball. Finally, each
of the ends of a branch swells to a little round sporangium, which is
limited by a partition (called sporangiolum, to distinguish it from
the larger ones), in which some, generally four, spores are formed in
the manner already known. When the sporangiola are alone, they have
such a peculiar appearance, with their richly-branched bearers, that
they can be taken for something quite different to the organs of the
_Mucor mucedo_, and were formerly not considered to belong to it. That
they really belong to the _Mucor_ is shown by the principal filament
which it bears, not always, but very often, ending with a large
sporangium, which is characteristic of the _Mucor mucedo_; it is still
more evident if we sow the spores of the sporangiolum, for, as it
germinates, a mycelium is developed, which, near a simple bearer, can
form large sporangia, and those form sporangiola, the first always
considerably preponderating in number, and very often exclusively. If
we examine a large number of specimens, we find every possible middle
form between the simple or less branched sporangia-bearers and the
typical sporangiola frills; and we arrive at last at the conclusion
simply to place the latter among the varieties of form which the
sporangia-bearer of the _Mucor mucedo_ shows, like every other typical
organic form within certain limits. On the other hand, propagation
organs, differing from those of the sporangia and their products,
belong to _Mucor mucedo_, which may be termed conidia. On the dung
(they are rare on any other substance) these appear at the same time,
or generally somewhat later, than the sporangia-bearers, and are not
unlike those to the naked eye. In a more accurate examination, they
appear different; a thicker, partition-less filament rises up and
divides itself, generally three-forked, at the length of one
millimetre, into several series of branchlets. The forked branches of
the last series bear under their points, which are mostly capillary,
short erect little ramuli, and these, with which the ends of the
principal branches articulate on their somewhat broad tops, several
spores and conidia, near one another; about fifteen to twenty are
formed at the end of each little ramulus. The peculiarities and
variations which so often appear in the ramification need not be
discussed here. After the articulation of the conidia, their bearers
sink together by degrees, and are quite destroyed. The ripe conidia
are round like a ball, their surface is scarcely coloured, and almost
wholly smooth. These conidioid forms were at first described as a
separate species under the name of _Botrytis Jonesii_. How, then, do
they belong to the _Mucor_?[t] That they appear gregariously is as
little proof of an original relation to one another, here as
elsewhere. Attempts to prove that the conidia and sporangia-bearers
originate on one and the same mycelium filament may possibly hereafter
succeed. Till now this has not been the case, and he who has ever
tried to disentangle the mass of filaments which exuberantly covers
the substratum of a _Mucor_ vegetation, which has reached so far as to
form conidia, will not be surprised that all attempts have hitherto
proved abortive. The suspicion of the connection founded on the
gregariously springing up, and external resemblance, is fully
justified, if we sow the conidia in a suitable medium, for example, in
a solution of sugar. They here germinate and produce a mycelium which
exactly resembles that of the _Mucor mucedo_, and, above all, they
produce in profusion the typical sporangia of the same on its bearers.
The latter are till now alone reproductions of conidia-bearers, and
have never been observed on mycelia which have grown out of conidia.

[Illustration: FIG. 32.--Small portion of _Botrytis Jonesii_.]

These phenomena of development appear in the _Mucor_ when it dwells on
a damp substance, which must naturally contain the necessary
nourishment for it, and is exposed to the atmospheric air. Its
mycelium represents at first strong branched utricles without
partitions; the branches are of the higher order, mostly divided into
rich and very fine-pointed ramuli. In old mycelium, and also in the
sporangia-bearers, the contents of which are mostly used for the
formation of spores, and the substratum of which is exhausted for our
fungus, short stationary pieces, filled with protoplasm, are very
often formed into cells through partitions in order to produce spores,
that is, grow to a new fruitful mycelium. These cells are called
gemmules, brooding cells, and resemble such vegetable buds and sprouts
of foliaceous plants which remain capable of development after the
organs of vegetation are dead, in order to grow, under suitable
circumstances, to new vegetating plants, as, for example, the bulbs of
onions, &c.

If we bring a vegetating mycelium of _Mucor mucedo_ into a medium
which contains the necessary nourishment for it, but excluded from the
free air, the formation of sporangia takes place very sparingly or not
at all, but that of gemmules is very abundant. Single interstitial
pieces of the ramuli, or even whole systems of branches, are quite
filled with a rich greasy protoplasm; the short pieces and ends are
bound by partitions which form particular, often tun-like or globular
cells; the longer ones are changed, through the formation of cross
partitions, into chains of similar cells; the latter often attain by
degrees strong, thick walls, and their greasy contents often pass into
innumerable drops of a very regular globular form and of equal size.
Similar appearances show themselves after the sowing of spores, which
are capable of germinating in the medium already described, from which
the air is excluded. Either short germinating utricles shoot forth,
which soon form themselves into rows of gemmules, or the spores swell
to large round bladders filled with protoplasm, and shoot forth on
various parts of their surface innumerable protuberances, which,
fixing themselves with a narrow basis, soon become round vesiculate
cells, and on which the same sprouts which caused their production are
repeated, formations which remind us of the fungus of fermentation
called globular yeast. Among all the known forms of gemmules we find a
variety which are intermediate, all of which show, when brought into a
normal condition of development, the same proportion, and the same
germination, as those we first described.

We have detailed rather at length the structure and development of one
of the most common of the Mucors, which will serve as an illustration
of the order. Other distinctions there may be which are of more
interest as defining the limits of genera, except such as may be
noticed when we come to write more specially of reproduction.

ASCOMYCETES.--Passing now to the _Ascomycetes_, which are especially
rich in genera and species, we must first, and but superficially,
allude to _Tuberacei_, an order of sporidiiferous fungi of subterranean
habit, and rather peculiar structure.[u] In this order an external
stratum of cells forms a kind of perithecium, which is more or less
developed in different genera. This encloses the hymenium, which is
sinuous, contorted, and twisted, often forming lacunæ. The hymenium in
some genera consists of elongated, nearly cylindrical asci, enclosing a
definite number of sporidia; in the true truffles and their
immediate allies, the asci are broad sacs, containing very large and
beautiful, often coloured, sporidia. These latter have either a
smooth, warted, spinulose, or lacunose epispore, and, as will be seen
from the figures in Tulasne's Monograph,[v] or those in the last
volume of Corda's great work,[w] are attractive microscopical objects.
In some cases, it is not difficult to detect paraphyses, but in
others they would seem to be entirely absent. A comparatively large
number have been discovered and recorded in Great Britain,[x] but of
those none are more suitable for study of general structure than the
ordinary truffle of the markets.

The structure of the remaining Ascomycetes can be studied under two
groups, _i.e._, the fleshy Ascomycetes, or, as they have been termed,
the Discomycetes, and the hard, or carbonaceous Ascomycetes,
sometimes called the Pyrenomycetes. Neither of these names gives an
accurate idea of the distinctions between the two groups, in the
former of which the discoid form is not universal, and the latter
contains somewhat fleshy forms. But in the Discomycetes the
hymenium soon becomes more or less exposed, and in the latter it is
enclosed in a perithecium. The Discomycetes are of two kinds, the
pileate and the cup-shaped. Of the pileate such a genus as _Gyromitra_
or _Helvella_ is, in a certain sense, analogous to the Agarics
amongst _Hymenomycetes_, with a superior instead of an inferior
hymenium, and enclosed, not naked, spores. Again, _Geoglossum_ is
somewhat analogous to _Clavaria_. Amongst the cup-shaped, _Peziza_
is an Ascomycetous _Cyphella_. But these are perhaps more fanciful
than real analogies.

Recently Boudier has examined one group of the cup-shaped Discomycetes,
the _Ascobolei_, and, by making a somewhat free use of his Memoir,[y] we
may arrive at a general idea of the structure in the cupulate
Discomycetes. They present themselves at first under the form of a
small rounded globule, and almost entirely cellular. This small
globule, the commencement of the receptacle, is not long in increasing,
preserving its rounded form up to the development of the asci. At this
period, under the influence of the rapid growth of these organs, it soon
produces at its summit a fissure of the external membrane, which
becomes a more marked depression in the marginate species. The
receptacle thus formed increases rapidly, becomes plane, more convex,
or more or less undulated at the margin, if at all of large size.
Fixed to the place where it is generated by some more or less
abundant mycelioid filaments, the receptacle becomes somewhat
cup-shaped and either stipitate or sessile, composed of the
receptacle proper and the hymenium.

[Illustration: FIG. 33.--Section of cup of _Ascobolus_. _a._ External
cells. _b._ Secondary layer. _c._ Subhymenial tissue (Janczenski).]

The receptacle proper comprehends the subhymenial tissue, the
parenchyma, and the external membrane. The subhymenial tissue is
composed of small compact cells, forming generally a more coloured and
dense stratum, the superior cells of which give rise to the asci and
paraphyses. The parenchyma is seated beneath this, and is generally of
interlaced filaments, of a looser consistency than the preceding,
united by intermediate cellules. The external membrane, which
envelopes the parenchyma, and limits the hymenium, differs from the
preceding by the cells often being polyhedric, sometimes transverse,
and united together, and sometimes separable. Externally it is
sometimes smooth, and sometimes granular or hairy.

The hymenium is, however, the most, important part, consisting of (1)
the paraphyses, (2) the asci, and sometimes (3) an investing mucilage.
The asci are always present, the paraphyses are sometimes rare, and
the mucilage in many cases seems to be entirely wanting.

The paraphyses, which are formed at the first commencement of the
receptacle, are at first very short, but soon elongate, and become
wholly developed before the appearance of the asci. They are linear,
sometimes branched and sometimes simple, often more or less thickened
at their tips; almost always they contain within them some oleaginous
granules, either coloured or colourless. Their special function seems
still somewhat obscure, and Boudier suggests that they may be
excitatory organs for the dehiscence of the asci. However this may be,
some mycologists are of opinion that, at least in some of the
Ascomycetes, the paraphyses are abortive asci, or, at any rate, that
abortive asci mixed with the paraphyses cannot be distinguished from
them.

The mucilage forms itself almost at the same time as the paraphyses,
and previous to the formation of the asci. This substance appears as a
colourless or yellowish mucilage, which envelopes the paraphyses and
asci, and so covers the hymenium with a shining coat.

The asci appear first at the base of the paraphyses, under the form of
oblong cells, filled with colourless protoplasm. By rapid growth, they
soon attain a considerable size and fulness, the protoplasm being
gradually absorbed by the sporidia, the first indication of which is
always the central nucleus. The mucilage also partly disappears, and
the asci, attaining their maturity, become quite distinct, each
enclosing its sporidia. But before they take their complete growth
they detach themselves from the subhymenial tissue, and being
attenuated towards their base, are forced upwards by pressure of the
younger asci, to, and in some instances beyond, the upper surface of
the disc. This phenomenon commences during the night, and continues
during the night and all the morning. It attains its height at
mid-day, and it is then that the slightest breath of air, the
slightest movement, suffices to cause dehiscence, which is generally
followed by a scarcely perceptible contractile motion of the
receptacle.

[Illustration: FIG. 34.--Asci, sporidia, and paraphyses of _Ascobolus_
(Boudier).]

There is manifestly a succession in formation and maturity of the asci
in a receptacle. In the true _Ascobolei_, in which the sporidia are
coloured, this may be more distinctly seen. At first some thin
projecting points appear upon the disc, the next day they are more
numerous, and become more and more so on following days, so as to
render the disc almost covered with raised black or crystalline
points;[z] these afterwards diminish day by day, until they ultimately
cease. The asci, after separation from the subhymenial tissue,
continue to lengthen, or it may be that their elasticity permits of
extension, during expulsion. Boudier considers that an amount of
elasticity is certain, because he has seen an ascus arrive at
maturity, eject its spores, and then make a sharp and considerable
movement of retraction, then the ascus returned again, immediately
towards its previous limits, always with a reduction in the number of
its contained sporidia.

The dehiscence of the asci takes place in the _Ascobolei_, in some
species of _Peziza_, _Morchella_, _Helvella_, and _Verpa_, by means of
an apical operculum, and in other _Pezizæ_, _Helotium_, _Geoglossum_,
_Leotia_, _Mitrula_, &c., by a fissure of the ascus. This operculum
may be the more readily seen when the ascus is coloured by a drop of
tincture of iodine.

The sporidia are usually four or eight, or some multiple of that
number, in each ascus, rarely four, most commonly eight. At a fixed
time the protoplasm, which at first filled the asci, disappears or is
absorbed in a mucilaginous matter, which occupies its place, in the
midst of which is a small nucleus, which is the rudiment of the first
spore; other spores are formed consecutively, and then the substance
separates into as many sections as there are sporidia. From this
period each sporidium seems to have a separate existence. All have a
nucleus, which is scarcely visible, often slightly granular, but which
is quite distinct from the oleaginous sporidioles so frequent amongst
the Discomycetes, and which are sometimes called by the same name. The
sporidia are at first a little smaller than when mature, and are
surrounded by mucilage. After this period the sporidia lose their
nebulous granulations, whilst still preserving their nucleus; their
outlines are distinct, and, amongst the true _Ascobolei_, commence
acquiring a rosy colour, the first intimation of maturity. This colour
manifests itself rapidly, accumulating exclusively upon the epispore,
which becomes of a deep rose, then violet, and finally violet blue, so
deep as sometimes to appear quite black. There are some modifications
in this coloration, since, in some species, it passes from a vinous
red to grey, then to black, or from rose-violet to brown.

The epispore acquires a waxy consistence by this pigmentation, so that
it may be detached in granules. It is to this particular consistency
of the epispore that the cracks so frequent in the coloured sporidia
of _Ascobolus_ are due, through contraction of the epispore. As they
approach maturity, the sporidia accumulate towards the apex of the
asci, and finally escape in the manner already indicated.

In all essential particulars there is a great similarity in the
structure of the other Discomycetes, especially in their reproductive
system. In most of them coloured sporidia are rare. In some the
receptacle is pileate, clavate, or inflated, whilst in _Stictis_ it is
very much reduced, and in the lowest form of all, _Ascomyces_, it is
entirely absent. In the _Phacidiacei_, the structure is very similar
to that of the _Elvellacei_, whilst the _Hysteriacei_, with greater
affinities with the latter, still tend towards the _Pyrenomycetes_ by
the more horny nature of the receptacle, and the greater tendency of
the hymenium to remain closed, at least when dry. In some species of
_Hysterium_, the sporidia are remarkably fine. M. Duby[AA] has
subjected this group to examination, and M. Tulasne partly so.[AB]

SPHÆRIACEI.--In this group there is considerable variation, within
certain limits. It contains an immense number of species, and these
are daily being augmented. The general feature in all is the
presence of a perithecium, which contains and encloses the hymenium,
and at length opening by a pore or ostiolum at the apex. In some
the perithecia are simple, in others compound; in some immersed in
a stroma, in others free; in some fleshy or waxy, in others
carbonaceous, and in others membranaceous. But in all there is this
important difference from the Ascomycetes we have already had under
consideration, that the hymenium is never exposed. The perithecium
consists usually of an external layer of cellular structure, which
is either smooth or hairy, usually blackish, and an internal
stratum of less compact cells, which give rise to the hymenium.

[Illustration: FIG. 35.--Perithecium of _Sphæria_ and Section.]

As in the _Discomycetes_, the hymenium consists of asci, paraphyses,
and mucilage, but the whole forms a less compact and more gelatinous
mass within the perithecium. The formation and growth of the asci and
sporidia differ little from what we have described, and when mature
the asci dehisce, and the sporidia alone are ejected from the
ostiolum. We are not aware that operculate asci have yet been
detected. It has been shown in some instances, and suspected in
others, that certain moulds, formerly classed with _Mucedines_ and
_Dematiei_, especially in the genus _Helminthosporium_, bear the
conidia of species of _Sphæria_, so that this may be regarded as one
form of fruit.

Perithecia, very similar externally to those of _Sphæria_, but
containing spores borne on slender pedicels and not enclosed in asci,
have had their relations to certain species of _Sphæria_ indicated,
and these are no longer regarded so much as species of _Hendersonia_
or _Diplodia_ as the pycnidia of _Sphæria_. Other and more minute
perithecia, containing minute, slender stylospores in great numbers,
formerly classed with _Aposphæria_, _Phoma_, &c., but are now
recognized as spermogonia containing the spermatia of _Sphæriæ_. How
these influence each other, when and under what circumstances the
spermatia are instrumental in impregnation of the sporidia, is still
matter of mystery. It is clear, however, that in all these conidia,
macrospores, microspores, and some spermatia, or by whatever names
they may be called, there exists a power of germination. Tulasne has
indicated in some instances five or six forms of fruit as belonging to
one fungus, of which the highest and most perfect condition is a
species of _Sphæria_.

[Illustration: FIG. 36.--_Uncinula adunca._]

PERISPORIACEI.--Except in the perithecia rupturing irregularly, and
not dehiscing by a pore, some of the genera in this group differ
little in structure from the _Sphæriacei_. On the other hand, the
_Erysiphei_ present important and very interesting features. They
occur chiefly on the green parts of growing plants. At first there is
a more or less profuse white mycelium.[AC] This gives rise to chains
of conidia (_Oidium_), and afterwards small sphæroid projections
appear at certain points on the mycelium. These enlarge, take an
orange colour, ultimately passing into brown, and then nearly black.
Externally these perithecia are usually furnished with long,
spreading, intertwined, or branching appendages, sometimes beautifully
branched or hooked at their tips. In the interior of the receptacles,
pear-shaped or ovate asci are formed in clusters, attached together at
the base, and containing two or more hyaline sporidia. Other forms of
fruit have also been observed on the same mycelium. In an exotic
genus, _Meliola_, the fulcra, or appendages, as well as the mycelium,
are black, otherwise it is very analogous to such a genus of
_Erysiphei_ as _Microsphæria_. In _Chætomium_, the perithecia bristle
with rigid, dark-coloured hairs, and the sporidia are coloured. Our
limits, however, will not permit of further elucidation of the complex
and varied structure to be found amongst fungi.[AD]

   [A] A curious case occurred some years since at Bury St. Edmunds,
       which may be mentioned here in connection with the development
       of these nodules. Two children had died under suspicious
       circumstances, and an examination of the body of the latter
       after exhumation was made, a report having arisen that the
       child died after eating mushrooms. As certain white nodules
       appeared on the inner surface of the intestines, it was at once
       hastily concluded that the spores of the mushroom had
       germinated, and that the nodules were infant mushrooms. This
       appeared to one of us so strange, that application was made for
       specimens, which were kindly forwarded, and a cursory glance
       was enough to convince us that they were not fungoid. An
       examination under the microscope further confirmed the
       diagnosis, and the application of nitric acid showed that the
       nodules were merely due to chalk mixture, which had been given
       to the child for the diarrhetic symptoms under which he
       succumbed.

   [B] Ehrenberg compared the whole structure of an Agaric with that
       of a mould, the mycelium corresponding with the hyphasma,
       the stem and pileus with the flocci, and the hymenium with
       the fructifying branchlets. The comparison is no less
       ingenious than true, and gives a lively idea of the connection
       of the more noble with the more humble fungi.--_Ehrb. de
       Mycetogenesi._

   [C] In _Paxillus involutus_ the hymenium may be readily torn off and
       unfolded.

   [D] This was well delineated in "Flora Danica," plate 834, as
       observed in _Coprinus comatus_ as long ago as 1780.

   [E] A. de Bary, "Morphologie und Physiologie der Pilze," in
       "Hofmeister's Handbuch," vol. ii. cap. 5, 1866, translated in
       "Grevillea," vol. i. p. 181.

   [F] "Die Pollinarien und Spermatien von _Agaricus_," in "Botanische
       Zeitung," Feb. 29 and March 7, 1856.

   [G] "Essai d'une Flore mycologique de la Région de Montpellier."
       Paris, 1863.

   [H] Hoffmann, "Botanische Zeitung," 1856, p. 139.

   [I] Corda, "Icones Fungorum hucusque cognitorum," iii. p. 41. Prague,
       1839.

   [J] Cooke, M. C., "Anatomy of a Mushroom," in "Popular Science
       Review," vol. viii. p. 380.

   [K] An attempt was made to show that, in _Agaricus melleus_, distinct
       asci were found, in a certain stage, on the gills or lamellæ.
       We have in vain examined the gills in various conditions, and
       could never detect anything of the kind. It is probable that
       the asci belonged to some species of _Hypomyces_, a genus of
       parasitic Sphæriaceous fungi.

   [L] It is not intended that the spores are always quaternate in
       _Agaricini_, though that number is constant in the more typical
       species. They sometimes exceed four, and are sometimes reduced
       to one.

   [M] The species long known as _Hydnum gelatinosum_ was examined by
       Mr. F. Currey in 1860 (_Journ. Linn. Soc._), and he came to the
       conclusion that it was not a good _Hydnum_. Since then it has
       been made the type of a new genus (Hydnogloea B. and Br.
       or, as called by Fries, in the new edition of "Epicrisis,"
       _Tremellodon_, Pers. Myc. Eur.), and transferred to the
       _Tremellini_. Currey says, upon examining the fructification,
       he was surprised to find that, although in its external
       characters it was a perfect _Hydnum_, it bore the fruit of a
       _Tremella_. If one of the teeth be examined with the
       microscope, it will be seen to consist of threads bearing
       four-lobed sporophores, and spores exactly similar to
       _Tremella_. It will thus be seen, he adds, that the plant
       is exactly intermediate between _Hydnei_ and _Tremellini_,
       forming, as it were, a stepping-stone from one to the other.

   [N] Tulasne, L. R. and C., "Observations on the Organization of the
       Tremellini," in "Ann. des Sci. Nat." 3^me sér. xix. (1853), pp.
       193, &c.

   [O] M. Léveillé, in "Ann. des Sci. Nat." 2^me sér. viii. p. 328; 3^me
       sér. ix. p. 127; also Bonorden, "Handbuch der Mycologie," p.
       151.

   [P] Tulasne, in "Ann. des Sci. Nat." (loc. cit.) xix. pl. x. fig. 29.
       Tulasne, "New Notes upon Tremellinous Fungi," in "Journ. Linn.
       Soc." vol. xiii. (1871), p. 31.

   [Q] Berkeley, M. J., "On the Fructification of Lycoperdon, Phallus,
       &c.," in "Ann. Nat. Hist." 1840, vol. iv. p. 158, pl. 5.
       Berkeley, M. J., "Introduction Crypt. Bot." p. 346.

   [R] Tulasne, L. R. and C., "Fungi Hypogæi." Paris. Berkeley and
       Broome, "British Hypogæous Fungi," in "Ann. Nat. Hist." 1846,
       xviii. p. 74. Corda, "Icones Fungorum," vol. vi. pl. vii.
       viii.

   [S] Tulasne, "Sur le Genre _Secotium_," in "Ann. des Sci. Nat."
       (1845), 3^me sér. vol. iv. p. 169, plate 9.

   [T] Tulasne, L. R. and C., "De la Fructification des _Scleroderma_
       comparée a celle des _Lycoperdon_ et des _Borista_," in "Ann.
       des Sci. Nat." 1842, xvii. p. 5. Tulasne, L. R. and C., "Sur
       les Genres Polysaccum et Geaster," in "Ann. des Sci. Nat."
       1842, xviii. p. 129, pl. 5 and 6.

   [U] Berkeley, "On the Fructification of Lycoperdon, &c.," in "Annals
       of Natural History" (1840), iv. p. 155.

   [V] Wigand, "Morphologie des Genres Trichia et Arcyria," in "Ann. des
       Sci. Nat." 4^me sér. xvi. p. 223.

   [W] Currey, "On Spiral Threads of Trichia," in "Quart. Journ. Micr.
       Science" (1855), iii. p. 17.

   [X] In some of the genera, as, for instance, in _Badhamia_,
       _Enerthenema_, and _Reticularia_, the spores are produced
       within delicate cells or cysts, which are afterwards absorbed.

   [Y] Tulasne, "Essai d'une Monographie des Nidulariées," in "Ann. des
       Sci. Nat." (1844), i. 41 and 64.

   [Z] Berkeley, M. J., "Introduction, Crypt. Bot." p. 330.

   [a] Berkeley, M. J., "Introduction, Crypt. Bot." p. 329.

   [b] In the _Cæomacei_ and _Pucciniæi_ the term "pseudospore" would be
       much more accurate.

   [c] Léveillé, "Sur la Disposition Méthodique des Urédinées," in "Ann.
       des Sci. Nat." (1847), vol. viii. p. 369.

   [d] De Bary, "Champignons Parasites," in "Ann. des Sci. Nat." 4^me
       sér. vol. xx.

   [e] Tulasne, "Mémoire sur les Urédinées, &c.," in "Ann. des Sci.
       Nat." (1854), vol. ii. p. 78.

   [f] De Bary, "Ueber die Brandpilze," Berlin, 1853.

   [g] Currey, in "Quart. Journ. Micr. Sci." (1857), vol. v. p. 119, pl.
       8, fig 13.

   [h] Cooke, "On Podisoma," in "Journal of Quekett Microscopical Club,"
       vol. ii. p. 255.

   [i] Tulasne, "Mémoire sur les Ustilaginées," in "Ann. des Sci. Nat."
       (1847), vii. pp. 12 and 73.

   [j] Corda, "Icones Fungorum," vol. iii. fig. 45.

   [k] Cooke, "On Podisoma," in "Quekett Journal," vol. ii. p. 255.

   [l] It may be a question whether _Graphiola_ is not more nearly
       allied to _Trichocoma_ (Jungh Fl. Crypt. Javæ, p. 10, f. 7)
       than to the genera with which it is usually associated.--M. J.
       B.

   [m] Cooke, "On Microscopic Moulds," in "Quekett Journal," vol. ii.
       plate 7.

   [n] _See_ "Dendryphium Fumosum," in "Quekett Journal," vol. ii. plate
       8; or, "Corda Prachtflora," plate 22.

   [o] De Bary, "Champignons Parasites," in "Ann. des Sci. Nat." 4^me
       sér. vol. xx.

   [p] Berkeley, "On the Potato Murrain," in "Journ. of Hort. Soc. of
       London," vol. i. (1846), p. 9.

   [q] De Bary, "On Mildew and Fermentation," p. 25, reprinted from
       "German Quarterly Magazine," 1872; De Bary, "Morphologie und
       Physiologie der Pilze," (1866), 201.

   [r] Cooke, "Handbook of British Fungi," vol. ii. p. 552.

   [s] De Bary, "On Mildew and Fermentation," in "Quarterly German
       Magazine," for 1872.

   [t] We are quite aware that Von Tieghem and Le Monnier, in "Ann. des
       Sci. Nat." 1873, p. 335, dispute that this belongs to _Mucor
       mucedo_, and assert that _Chætocladium Jonesii_ is itself a
       true _Mucor_, with monosporous sporangia.

   [u] Vittadini, "Monographia Tuberacearum," 1831.

   [v] Tulasne, "Fungi Hypogæi," 1851.

   [w] Corda, "Icones Fungorum," vol. vi.

   [x] Berkeley and Broome, in "Ann. of Nat. Hist." 1st ser. vol. xviii.
       (1846), p. 73; Cooke, in "Seem. Journ. Bot."

   [y] Boudier (E.), "Mémoire sur les Ascobolés," in "Ann. des Sci.
       Nat." 5^me sér. vol. x. (1869).

   [z] Only in some of the Discomycetes are the asci exserted.

  [AA] Duby, "Mémoire sur la Tribu des Hysterinées," 1861.

  [AB] Tulasne, "Selecta Fungorum Carpologia," vol. iii.

  [AC] Tulasne, "Selecta Fungorum Carpologia," vol. i. Léveillé,
       "Organisation, &c., sur l'Érysiphé," in "Ann. des Sci. Nat."
       (1851), vol. xv. p. 109.

  [AD] Other works besides those already cited, which may be consulted
       with advantage on structure, are--

       Tulasne, L. R. and C., various articles in "Annales des
       Sciences Naturelles," série iii. and iv.

       Hoffmann, "Icones Analyticæ Fungorum."

       De Bary, "Der Ascomyceten." Leipzic, 1863.

       Berkeley, M. J., "Introduction to Cryptogamic Botany."

       Seynes, J. de, "Recherches, &c., des Fistulines." Paris, 1874.

       Winter, G., "Die Deutschen Sordarien." 1874.

       Corda, J., "Prachtflora." Prague, 1840.

       De Bary, "Über der Brandpilze." 1853.

       Brefeld, O., "Botan. Untersuch. ü Schimmelpilze."

       Fresenius, G., "Beiträge zur Mykologie." 1850.

       Von Tieghem and Le Monnier, in "Annales des Sciences
       Naturelles" (1873), p. 335.

       Cornu, M., "Sur les Saprolegniées," in "Ann. des Sci. Nat."
       5^me sér. xv. p. 5.

       Janczenski, "Sur l'Ascobolus furfuraceus," in "Ann. des Sci.
       Nat." 5^me sér. xv. p. 200.

       De Bary and Woronin, "Beiträge zur Morphologie und Physiologie
       der Pilze." 1870.

       Bonorden, H. F., "Abhandlungen aus dem Gebiete der Mykologie."
       1864.

       Coemans, E., "Spicilége Mycologique." 1862, etc.



III

CLASSIFICATION


A work of this kind could not be considered complete without some
account of the systematic arrangement or classification which these
plants receive at the hands of botanists. It would hardly avail to
enter too minutely into details, yet sufficient should be attempted to
enable the reader to comprehend the value and relations of the
different groups into which fungi are divided. The arrangement
generally adopted is based upon the "Systema Mycologicum" of Fries, as
modified to meet the requirements of more recent microscopical
researches by Berkeley in his "Introduction,"[A] and adopted in
Lindley's "Vegetable Kingdom." Another arrangement was proposed by
Professor de Bary,[B] but it has never met with general acceptance.

In the arrangement to which we have alluded, all fungi are divided
into two primary sections, having reference to the mode in which the
fructification is produced. In one section, the spores (which occupy
nearly the same position, and perform similar functions, to the seeds
of higher plants) are naked; that is, they are produced on spicules,
and are not enclosed in cysts or capsules. This section is called
SPORIFERA, or spore-bearing, because, by general consent, the term
_spore_ is limited in fungi to such germ-cells as are not produced in
cysts. The second section is termed SPORIDIIFERA, or sporidia-bearing,
because in like manner the term _sporidia_ is limited to such
germ-cells as are produced in cells or cysts. These cysts are
respectively known as _sporangia_, and _asci_ or _thecæ_. The true
meaning and value of these divisions will be better comprehended when
we have detailed the characters of the families composing these two
divisions.

First, then, the section SPORIFERA contains four families, in two of
which a hymenium is present, and in two there is no proper hymenium.
The term _hymenium_ is employed to represent a more or less expanded
surface, on which the fructification is produced, and is, in fact, the
fruit-bearing surface. When no such surface is present, the fruit is
borne on threads, proceeding direct from the root-like filaments of
the mycelium, or an intermediate kind of cushion or stroma. The two
families in which an hymenium is present are called _Hymenomycetes_
and _Gasteromycetes_. In the former, the hymenium is exposed; in the
latter, it is at first enclosed. We must examine each of these
separately.

The common mushroom may be accepted, by way of illustration, as a type
of the family _Hymenomycetes_, in which the hymenium is exposed, and
is, in fact, the most noticeable feature in the family from which its
name is derived. The pileus or cap bears on its under surface
radiating plates or gills, consisting of the hymenium, over which are
thickly scattered the basidia, each surmounted by four spicules, and
on each spicule a spore. When mature, these spores fall freely upon
the ground beneath, imparting to it the general colour of the spores.
But it must be observed that the hymenium takes the form of
gill-plates in only one order of _Hymenomycetes_, namely, the
_Agaricini_; and here, as in _Cantharellus_, the hymenium is sometimes
spread over prominent veins rather than gills. Still further
divergence is manifest in the _Polyporei_, in which order the hymenium
lines the inner surface of pores or tubes, which are normally on the
under side of the pileus. Both these orders include an immense number
of species, the former more or less fleshy, the latter more or less
tough and leathery. There are still other forms and orders in this
family, as the _Hydnei_, in which the hymenium clothes the surface of
prickles or spines, and the _Auricularini_, in which the hymenium is
entirely or almost even. In the two remaining orders, there is a
still further divergence from the mushroom form. In the one called
_Clavariei_, the entire fungus is either simply cylindrical or
club-shaped, or it is very much branched and ramified. Whatever form
the fungus assumes, the hymenium covers the whole exposed surface. In
the _Tremellini_, a peculiar structure prevails, which at first seems
to agree but little with the preceding. The whole plant is gelatinous
when fresh, lobed and convolute, often brain-like, and varying in
size, according to species, from that of a pin's head to that of a
man's head. Threads and sporophores are imbedded in the gelatinous
substance,[C] so that the fertile threads are in reality not compacted
into a true hymenium. With this introduction we may state that the
technical characters of the family are thus expressed:--

_Hymenium free, mostly naked, or, if enclosed at first, soon
exposed; spores naked, mostly quaternate, on distinct spicules_ =
HYMENOMYCETES.

[Illustration: FIG. 37.--_Agaricus nudus._]

In this family some mycologists believe that fungi attain the highest
form of development of which they are capable, whilst others contend
that the fructification of the _Ascomycetes_ is more perfect, and that
some of the noblest species, such as the pileate forms, are entitled
to the first rank. The morel is a familiar example. Whatever may be
said on this point, it is incontrovertible that the noblest and most
attractive, as well as the largest, forms are classed under the
_Hymenomycetes_.

In _Gasteromycetes_, the second family, a true hymenium is also
present, but instead of being exposed it is for a long time enclosed
in an outer peridium or sac, until the spores are fully matured, or
the fungus is beginning to decay. The common puff-ball (_Lycoperdon_)
is well known, and will illustrate the principal feature of the
family. Externally there is a tough coat or peridium, which is at
first pale, but ultimately becomes brown. Internally is at first a
cream-coloured, then greenish, cellular mass, consisting of the
sinuated hymenium and young spores, which at length, and when the
spores are fully matured become brownish and dusty, the hymenium
being broken up into threads, and the spores become free. In earlier
stages, and before the hymenium is ruptured, the spores have been
found to harmonize with those of _Hymenomycetes_ in their mode of
production, since basidia are present surmounted each by four
spicules, and each spicule normally surmounted by a spore.[D] Here is,
therefore, a cellular hymenium bearing quaternary spores, but,
instead of being exposed, this hymenium is wholly enclosed within
an external sac or peridium, which is not ruptured until the
spores are fully matured, and the hymenium is resolved into
threads, together forming a pulverulent mass. It must, however, be
borne in mind, that in only some of the orders composing this
family is the hymenium thus evanescent, in others being more or less
permanent, and this has led naturally enough to the recognition of
two sub-families, in one of which the hymenium is more or less
permanent, thus following the Hymenomycetous type; and in the
other, the hymenium is evanescent, and the dusty mass of spores tends
more towards the _Coniomycetes_, this being characterized as the
coniospermous (or dusty-spored) sub-family.

The first sub-family includes, first of all, the _Hypogæi_, or
subterranean species. And here again it becomes necessary to remind
the reader that all subterranean fungi are not included in this
order, inasmuch as some, of which the truffle is an example, are
sporidiiferous, developing their sporidia in asci. To these allusion
must hereafter be made. In the _Hypogæi_, the hymenium is permanent and
convoluted, leaving numerous minute irregular cavities, in which the
spores are produced on sporophores. When specimens are very old and
decaying, the interior may become pulverulent or deliquescent. The
structure of subterranean fungi attracted the attention of Messrs.
Tulasne, and led to the production of a splendid monograph on the
subject.[E] Another order belonging to this sub-family is the
_Phalloidei_, in which the volva or peridium is ruptured whilst the
plant is still immature, and the hymenium when mature becomes
deliquescent. Not only are some members of this order most singular in
appearance, but they possess an odour so foetid as to be unapproached in
this property by any other vegetable production.[F] In this order, the
inner stratum of the investing volva is gelatinous. When still young,
and previous to the rupture of the volva, the hymenium presents sinuous
cavities in which the spores are produced on spicules, after the
manner of _Hymenomycetes_.[G] _Nidulariacei_ is a somewhat aberrant
order, presenting a peculiar structure. The peridium consists of two or
three coats, and bursts at the apex, either irregularly or in a
stellate manner, or by the separation of a little lid. Within the
cavity are contained one or more secondary receptacles, which are
either free or attached by elastic threads to the common receptacle.
Ultimately the secondary receptacles are hollow, and spores are
produced in the interior, borne on spicules.[H] The appearance in some
genera as of a little bird's-nest containing eggs has furnished the
name to the order.

The second sub-family contains the coniospermous puff-balls, and
includes two orders, in which the most readily distinguishable
feature is the cellular condition of the entire plant, in its earlier
stages, in the _Trichogastres_, and the gelatinous condition of
the early state of the _Myxogastres_. Both are ultimately resolved
internally into a dusty mass of threads and spores. In the former,
the peridium is either single or double, occasionally borne on a
stem, but usually sessile. In _Geaster_, the "starry puff-balls," the
outer peridium divides into several lobes, which fall back in a
stellate manner, and expose the inner peridium, like a ball in the
centre. In _Polysaccum_, the interior is divided into numerous
cells, filled with secondary peridia. The mode of spore-production
has already been alluded to in our remarks on _Lycoperdon_. All
the species are large, as compared with those of the following
sub-family, and one species of _Lycoperdon_ attains an enormous
size. One specimen recorded in the "Gardener's Chronicle" was
three feet four inches in circumference, and weighed nearly ten
pounds. In the _Myxogastres_, the early stage has been the subject of
much controversy. The gelatinous condition presents phenomena so
unlike anything previously recorded in plants, that one learned
professor[I] did not hesitate to propose their exclusion from the
vegetable, and recognition in the animal, kingdom as associates of
the Gregarines. When mature, the spores and threads so much resemble
those of the _Trichogastres_, and the little plants themselves are
so veritably miniature puff-balls, that the theory of their animal
nature did not meet with a ready acceptance, and is now virtually
abandoned. The characters of the family we have thus briefly reviewed
are tersely stated, as--

_Hymenium more or less permanently concealed, consisting in most cases
of closely-packed cells, of which the fertile ones bear naked spores
on distinct spicules, exposed only by the rupture or decay of the
investing coat or peridium_ = GASTEROMYCETES.

[Illustration: FIG. 38.--_Scleroderma vulgare_, Fr.]

[Illustration: FIG. 39.--_Ceuthospora phacidioides_ (Greville).]

We come now to the second section of the _Sporifera_, in which no
definite hymenium is present. And here we find also two families, in
one of which the dusty spores are the prominent feature, and hence
termed _Coniomycetes_; the other, in which the threads are most
noticeable, is _Hyphomycetes_. In the former of these, the reproductive
system seems to preponderate so much over the vegetative, that the
fungus appears to be all spores. The mycelium is often nearly
obsolete, and the short pedicels so evanescent, that a rusty or sooty
powder represents the mature fungus, infesting the green parts of
living plants. This is more especially true of one or two orders. It
will be most convenient to recognize two artificial sub-families for
the purpose of illustration, in one of which the species are developed
on living, and in the other on dead, plants. We will commence with the
latter, recognizing first those which are developed beneath the
cuticle, and then those which are superficial. Of the sub-cuticular,
two orders may be named as the representatives of this group in
Britain, these are the _Sphæronemei_, in which the spores are contained
in a more or less perfect perithecium, and the _Melanconiei_, in which
there is manifestly none. The first of these is analogous to the
_Sphæriacei_ of _Ascomycetous_ fungi, and probably consists largely of
spermogonia of known species of _Sphæria_, the relations of which have
not hitherto been traced. The spores are produced on slender threads
springing from the inner wall of the perithecium, and, when mature, are
expelled from an orifice at the apex. This is the normal condition, to
which there are some exceptions. In the _Melanconiei_, there is no
true perithecium, but the spores are produced in like manner upon a kind
of stroma or cushion formed from the mycelium, and, when mature, are
expelled through a rupture of the cuticle beneath which they are
generated, often issuing in long gelatinous tendrils. Here, again,
the majority of what were formerly regarded as distinct species have
been found, or suspected, to be forms of higher fungi. The _Torulacei_
represent the superficial fungi of this family, and these consist of a
more or less developed mycelium, which gives rise to fertile threads,
which, by constriction and division, mature into moniliform chains
of spores. The species mostly appear as blackish velvety patches or
stains on the stems of herbaceous plants and on old weathered wood.

Much interest attaches to the other sub-family of _Coniomycetes_, in which
the species are produced for the most part on living plants. So much
has been discovered during recent years of the polymorphism which
subsists amongst the species in this section, that any detailed
classification can only be regarded as provisional. Hence we shall
proceed here upon the supposition that we are dealing with autonomous
species. In the first place, we must recognize a small section in which
a kind of cellular peridium is present. This is the _Æcidiacei_, or order
of "cluster cups." The majority of species are very beautiful objects
under the microscope; the peridia are distinctly cellular, and white or
pallid, produced beneath the cuticle, through which they burst, and,
rupturing at the apex, in one genus in a stellate manner, so that the
teeth, becoming reflexed, resemble delicate fringed cups, with the
orange, golden, brown, or whitish spores or pseudospores nestling in the
interior.[J] These pseudospores are at first produced in chains, but
ultimately separate. In many cases these cups are either accompanied or
preceded by spermogonia. In two other orders there is no peridium. In the
_Cæomacei_, the pseudospores are more or less globose or ovate, sometimes
laterally compressed and simple; and in _Pucciniæi_, they are elongated,
often subfusiform and septate. In both, the pseudospores are produced
in tufts or clusters _direct from the mycelium. The Cæomacei_ might
again be subdivided into _Ustilagines_[K] and _Uredines_.[L] In the
former, the pseudospores are mostly dingy brown or blackish, and in the
latter more brightly coloured, often yellowish. The _Ustilagines_
include the smuts and bunt of corn-plants, the _Uredines_ include the
red rusts of wheat and grasses. In some of the species included in the
latter, two forms of fruit are found. In _Melampsora_, the summer
pseudospores are yellow, globose, and were formerly classed as a species
of _Lecythea_, whilst the winter pseudospores are brownish, elongated,
wedge-shaped by compression, and compact. The _Pucciniæi_[M] differ
primarily in the septate pseudospores, which in one genus (_Puccinia_) are
uniseptate; in _Triphragmium_, they are biseptate; in _Phragmidium_,
multiseptate; and in _Xenodochus_, moniliform, breaking up into
distinct articulations. It is probable that, in all of these, as is
known to be the case in most, the septate pseudospores are preceded or
accompanied by simple pseudospores, to which they are mysteriously
related. There is still another, somewhat singular, group usually
associated with the _Pucciniæi_, in which the septate pseudospores are
immersed in gelatin, so that in many features the species seem to
approach the _Tremellini_. This group includes two or three genera, the
type of which will be found in _Podisoma_.[N] These fungi are parasitic on
living junipers in Britain and North America, appearing year after year
upon the same gouty swellings of the branches, in clavate or horn-shaped
gelatinous processes of a yellowish or orange colour. Anomalous as it
may at first sight appear to include these tremelloid forms with the
dust-like fungi, their relations will on closer examination be more fully
appreciated, when the form of pseudospores, mode of germination, and
other features are taken into consideration, especially when compared with
_Podisoma Ellisii_, already alluded to. This family is technically
characterized as,--

_Distinct hymenium none. Pseudospores either solitary or concatenate,
produced on the tips of generally short threads, which are either
naked or contained in a perithecium, rarely compacted into a
gelatinous mass, at length producing minute spores_ = CONIOMYCETES.

The last family of the sporifera is _Hyphomycetes_, in which the
threads are conspicuously developed. These are what are more
commonly called "moulds," including some of the most elegant and
delicate of microscopic forms. It is true of many of these, as well
as of the _Coniomycetes_, that they are only conidial forms of
higher fungi; but there will remain a very large number of species
which, as far as present knowledge extends, must be accepted as
autonomous. In this family, we may again recognize three subdivisions,
in one of which the threads are more or less compacted into a common
stem, in another the threads are free, and in the third the threads
can scarcely be distinguished from the mycelium. It is this latter
group which unites the _Hyphomycetes_ with the _Coniomycetes_, the
affinities being increased by the great profusion with which the
spores are developed. The first group, in which the fertile threads
are united so as to form a compound stem, consists of two small
orders, the _Isariacei_ and the _Stilbacei_, in the former of which
the spores are dry, and in the latter somewhat gelatinous. Many of
the species closely imitate forms met with in the _Hymenomycetes_,
such as _Clavaria_; and, in the genus _Isaria_, it is almost beyond
doubt that the species found on dead insects, moths, spiders,
flies, ants, &c., are merely the conidiophores of species of
_Torrubia_.[O]

The second group is by far the largest, most typical, and attractive
in this family. It contains the black moulds and white moulds,
technically known as the _Dematiei_ and the _Mucedines_. In the first,
the threads are more or less corticated, that is, the stem has a
distinct investing membrane, which peels off like a bark; and the
threads, often also the spores, are dark-coloured, as if charred or
scorched. In many cases, the spores are highly developed, large,
multiseptate, and nucleate, and seldom are spores and threads
colourless or of bright tints. In the _Mucedines_, on the contrary,
the threads are never coated, seldom dingy, mostly white or of pure
colours, and the spores have less a tendency to extra development or
multiplex septation. In some genera, as in _Peronospora_ for
instance,[P] a secondary fruit is produced in the form of resting
spores from the mycelium; and these generate zoospores as well as the
primary spores, similar to those common in _Algæ_. This latter genus
is very destructive to growing plants, one species being the chief
agent in the potato disease, and another no less destructive to crops
of onions. The vine disease is produced by a species of _Oidium_,
which is also classed with _Mucedines_, but which is really the
conidiiferous form of _Erysiphe_. In other genera, the majority of
species are developed on decaying plants, so that, with the exception
of the two genera mentioned, the _Hyphomycetes_ exert a much less
baneful influence on vegetation than the _Coniomycetes_. The last
section, including the _Sepedoniei_, has been already cited as
remarkable for the suppression of the threads, which are scarcely to
be distinguished from the mycelium; the spores are profuse, nestling
on the floccose mycelium; whilst in the _Trichodermacei_, the spores
are invested by the threads, as if enclosed in a sort of false
peridium. A summary of the characters of the family may therefore be
thus briefly expressed:--

_Filamentous; fertile threads naked, for the most part free or loosely
compacted, simple or branched, bearing the spores at their apices,
rarely more closely packed, so as to form a distinct common stem_ =
HYPHOMYCETES.

[Illustration: FIG. 40.--_Rhopalomyces candidus._]

Having thus disposed of the _Sporifera_, we must advert to the two
families of _Sporidiifera_. As more closely related to the _Hyphomycetes_,
the first of these to be noticed is the _Physomycetes_, in which there
is no proper hymenium, and the threads proceeding from the mycelium bear
vesicles containing an indefinite number of sporidia. The fertile threads
are either free or only slightly felted. In the order _Antennariei_, the
threads are black and moniliform, more or less felted, bearing irregular
sporangia. A common fungus named _Zasmidium cellare_, found in cellars,
and incrusting old wine bottles, as with a blackened felt, belongs to
this order. The larger and more highly-developed order, _Mucorini_,
differs in the threads, which are simple or branched, being free, erect,
and bearing the sporangia at the tips of the thread, or branches. Some of
the species bear great external resemblance to _Mucedines_ until the
fruit is examined, when the fructifying heads, commonly globose or ovate,
are found to be delicate transparent vesicles, enclosing a large number
of minute sporidia; when mature, the sporangia burst and the sporidia
are set free. In some species, it has long been known that a sort of
conjugation takes place between opposite threads, which results in the
formation of a sporangium.[Q] None of these species are destructive to
vegetation, appearing only upon decaying, and not upon living, plants.
A state approaching putrescence seems to be essential to their vigorous
development. The following characters may be compared with those of
the family preceding it:--

_Filamentous, threads free or only slightly felted, bearing vesicles,
which contain indefinite sporidia_ = PHYSOMYCETES.

[Illustration: FIG. 41.--_Mucor caninus._]

In the last family, the _Ascomycetes_, we shall meet with a very great
variety of forms, all agreeing in producing sporidia contained in
certain cells called asci, which are produced from the hymenium. In
some of these, the asci are evanescent, but in the greater number are
permanent. In _Onygenei_, the receptacle is either club-shaped or
somewhat globose, and the peridium is filled with branched threads,
which produce asci of a very evanescent character, leaving the
pulverulent sporidia to fill the central cavity. The species are all
small, and singular for their habit of affecting animal substances,
otherwise they are of little importance. The _Perisporiacei_, on the
other hand, are very destructive of vegetation, being produced, in the
majority of cases, on the green parts of growing plants. To this order
the hop mildew, rose mildew, and pea mildew belong. The mycelium is
often very much developed, and in the case of the maple, pea, hop, and
some others, it covers the parts attacked with a thick white coating,
so that from a distance the leaves appear to have been whitewashed.
Seated on the mycelium, at the first as little orange points, are the
perithecia, which enlarge and become nearly black. In some species,
very elegant whitish appendages radiate from the sides of the
perithecia, the variations in which aid in the discrimination of
species. The perithecia contain pear-shaped asci, which spring from
the base and enclose a definite number of sporidia.[R] The asci
themselves are soon dissolved. Simultaneously with the development of
sporidia, other reproductive bodies are produced direct from the
mycelium, and in some species as many as five different kinds of
reproductive bodies have been traced. The features to be remembered in
_Perisporiacei_, as forming the basis of their classification, are,
that the asci are saccate, springing from the base of the perithecia,
and are soon absorbed. Also that the perithecia themselves are not
perforated at the apex.

The four remaining orders, though large, can be easily characterized.
In _Tuberacei_, all the species are subterranean, and the hymenium is
mostly sinuated. In _Elvellacei_, the substance is more or less
fleshy, and the hymenium is exposed. In _Phacidiacei_, the substance
is hard or leathery, and the hymenium is soon exposed. And in
_Sphæriacei_, although the substance is variable, the hymenium is
never exposed, being enclosed in perithecia with a distinct opening at
the apex, through which the mature spores escape. Each of these four
orders must be examined more in detail. The _Tuberacei_, or
subterranean _Ascomycetes_, are analogous to the _Hypogæi_ of the
_Gasteromycetes_. The truffle is a familiar and highly prized example.
There is a kind of outer peridium, and the interior consists of a
fleshy hymenium, more or less convoluted, sometimes sinuous and
confluent, so as to leave only minute elongated and irregular
cavities, and sometimes none at all, the two opposing faces of the
hymenium meeting and coalescing.[S] Certain privileged cells of the
hymenium swell, and ultimately become asci, enclosing a definite
number of sporidia. The sporidia in many cases are large, reticulated,
echinulate or verrucose, and mostly somewhat globose. In the genus
_Elaphomyces_, the asci are more than commonly diffluent.

The _Elvellacei_ are fleshy in substance, or somewhat waxy, sometimes
tremelloid. There is no peridium, but the hymenium is always exposed.
There is a great variety of forms, some being pileate, and others
cup-shaped, as there is also a great variation in size, from the
minute _Peziza_, small as a grain of sand, to the large _Helvella
gigas_, which equals in dimensions the head of a child. In the pileate
forms, the stroma is fleshy and highly developed; in the cup-shaped,
it is reduced to the external cells of the cup which enclose the
hymenium. The hymenium itself consists of elongated fertile cells, or
asci, mixed with linear thread-like barren cells, called paraphyses,
which are regarded by some authors as barren asci. These are placed
side by side in juxtaposition with the apex outwards. Each ascus
contains a definite number of sporidia, which are sometimes coloured.
When mature, the asci explode above, and the sporidia may be seen
escaping like a miniature cloud of smoke in the light of the mid-day
sun. The disc or surface of the hymenium is often brightly coloured in
the genus _Peziza_; tints of orange, red, and brown having the
predominance.

In _Phacidiacei_, the substance is hard and leathery, intermediate
between the fleshy _Elvellacei_ and the more horny of the _Sphæriacei_.
The perithecia are either orbicular or elongated, and the hymenium soon
becomes exposed. In some instances, there is a close affinity with
the _Elvellacei_, the exposed hymenium being similar in structure,
but in all the disc is at first closed. In orbicular forms, the
fissure takes place in a stellate manner from the centre, and the
teeth are reflexed. In the _Hysteriacei_, where the perithecia are
elongated, the fissure takes place throughout their length. As a
rule, the sporidia are more elongated, more commonly septate, and more
usually coloured, than in _Elvellacei_. Only a few solitary instances
occur of individual species that are parasitic on living plants.

[Illustration: FIG. 42.--_Sphæria aquila._]

In the _Sphæriacei_, the substance of the stroma (when present) and of
the perithecia is variable, being between fleshy and waxy in
_Nectriei_, and tough, horny, sometimes brittle, in _Hypoxylon_. A
perithecium, or cell excavated in the stroma which fulfils the
functions of a perithecium, is always present. The hymenium lines the
inner walls of the perithecium, and forms a gelatinous nucleus,
consisting of asci and paraphyses. When fully mature, the asci are
ruptured and the sporidia escape by a pore which occupies the apex of
the perithecium. Sometimes the perithecia are solitary or scattered,
and sometimes gregarious, whilst in other instances they are closely
aggregated and immersed in a stroma of variable size and form.
Conidia, spermatia, pycnidia, &c., have been traced to and associated
with some species, but the history of others is still obscure. Many of
the coniomycetous forms grouped under the _Sphæronemei_ are probably
conditions of the _Sphæriacei_, as are also the _Melanconiei_, and
some of the _Hyphomycetes_. A very common fungus, for instance, which
is abundant on sticks and twigs, forming rosy or reddish pustules the
size of a millet seed, formerly named _Tubercularia vulgaris_, is
known to be the conidia-bearing stroma of the sphæriaceous fungus,
_Nectria cinnabarina_;[T] and so with many others. The following are
the technical characters of the family:--

_Fruit consisting of sporidia, mostly definite, contained in asci,
springing from a naked or enclosed stratum of fructifying cells and
forming a hymenium or nucleus_ = ASCOMYCETES.

If the characters of the different families are borne in mind, there
will be but little difficulty in assigning any fungus to the order to
which it belongs by means of the foregoing remarks. For more minute
information, and for analytical tables of the families, orders, and
genera, we must refer the student to some special systematic work,
which will present fewer difficulties, if he keeps in mind the
distinctive features of the families.[U]

To assist in this we have given on the following page an analytical
arrangement of the families and orders, according to the system
recognized and adopted in the present volume. It is, in all essential
particulars, the method adopted in our "Handbook," based on that of
Berkeley's "Introduction" and "Outlines."

   [A] Rev. M. J. Berkeley, "Introduction to Cryptogamic Botany" (1857),
       London, pp. 235 to 372.

   [B] De Bary, in "Streinz Nomenclator Fungorum," p. 722.

   [C] Tulasne, L. and C. R., "Observations sur l'Organisation des
       Trémellinées," "Ann. des Sci. Nat." 1853, xix. p. 193.

   [D] Berkeley, M. J., "On the Fructification of _Lycoperdon_,
       _Phallus_, and their Allied Genera," in "Ann. of Nat. Hist."
       (1840), vol. iv. p. 155; "Ann. des Sci. Nat." (1839), xii. p.
       163. Tulasne, L. R. and C., "De la Fructification des
       _Scléroderma_ comparée à celle des _Lycoperdon_ et des
       _Bovista_," in "Ann. des Sci. Nat." 2^me sér. xvii. p. 5.

   [E] Tulasne, L. R. and C., "Fungi Hypogæi," Paris, 1851;
       "Observations sur le Genre Elaphomyces," in "Ann. des Sci.
       Nat." 1841, xvi. 5.

   [F] _Stapeliæ_ in this respect approach most closely to the
       _Phalloidei_.

   [G] Berkeley, in "Ann. Nat. Hist." vol. iv. p. 155.

   [H] Tulasne, L. R. and C., "Recherches sur l'Organisation et le Mode
       de Fructification des Nidulariées," "Ann. des Sci. Nat."
       (1844), i. p. 41.

   [I] De Bary, A., "Des Myxomycètes," in "Ann. des Sci. Nat." 4^me sér.
       xi. p. 153; "Bot. Zeit." xvi. p. 357.

   [J] Corda, "Icones Fungorum," vol. iii. fig. 45.

   [K] Tulasne, "Mémoire sur les Ustilaginées," "Ann. des Sci. Nat."
       (1847), vii. 12-73.

   [L] Tulasne, "Mémoire sur les Urédinées," "Ann. des Sci. Nat."
       (1854), ii. 78.

   [M] Tulasne, "Sur les Urédinées," "Ann. des Sci. Nat." 1854, ii. pl.
       9.

   [N] Cooke, M. C., "Notes on _Podisoma_," in "Journ. Quek. Micr.
       Club," No. 17 (1871), p. 255.

   [O] Tulasne, L. R. and C., "Selecta Fungorum Carpologia," vol. iii.
       pp. 4-19.

   [P] De Bary, A., "Recherches sur les Champignons Parasites," in "Ann.
       des Sci. Nat." 4^me sér. xx. p. 5; "Grevillea," vol. i. p.
       150.

   [Q] A. de Bary, translated in "Grevillea," vol. i. p. 167; Tulasne,
       "Ann. des Sci. Nat." 5^me sér. (1866), p. 211.

   [R] Léveillé, J. H., "Organisation, &c., de l'Érysiphé," in "Ann. des
       Sci. Nat." (1851), xv. p. 109.

   [S] Tulasne, L. R. and C., "Fungi Hypogæi," Paris; Vittadini, C.,
       "Monographia Tuberacearum," Milan, 1831.

   [T] "A Currant Twig and Something on it," in "Gardener's Chronicle"
       for January 28, 1871.

   [U] Berkeley, M. J., "Introduction to Cryptogamic Botany," London,
       1857; Cooke, M. C., "Handbook of British Fungi," London, 1871 ;
       Corda, A. C. J., "Anleitung zum Studium der Mycologie," Prag,
       1842; Kickx, J., "Flore Cryptogamique des Flanders," Gand,
       1867; Fries, E., "Systema Mycologicum," Lund, 1830; Fries, E.,
       "Summa Vegetabilium Scandinaviæ," 1846; Secretan, L.,
       "Mycographie Suisse," Geneva, 1833; Berkeley, M. J., "Outlines
       of British Fungology," London, 1860.


              TABULAR ARRANGEMENT OF FAMILIES AND ORDERS.

   DIVISION I.             SPORIFERA.               _Spores naked._

I. Hymenium free, mostly naked, or soon exposed         HYMENOMYCETES.
   Hymenium normally inferior--
     Fruit-bearing surface lamellose                    _Agaricini._
     Fruit-bearing surface porous or tubular            _Polyporei._
     Fruit-bearing surface clothed with prickles        _Hydnei._
     Fruit-bearing surface even or rugose               _Auricularini._
   Hymenium superior or encircling--
     Clavate, or branched, rarely lobed                 _Clavariei._
     Lobed, convolute, or disc-like, gelatinous         _Tremellini._

II. Hymenium enclosed in a peridium, ruptured when
     mature                                             GASTEROMYCETES.
   Hymenomycetous--
     Subterranean, naked or enclosed                    _Hypogæi._
     Terrestrial, hymenium deliquescent                 _Phalloidei._
     Peridium enclosing sporangia, containing spores    _Nidulariacei._
   Coniospermous--
     Stipitate, hymenium convolute, drying into a
      dusty mass, enclosed in a volva                   _Podaxinei._
     Cellular at first, hymenium drying up into a
      dusty mass of threads and spores                  _Trichogastres._
     Gelatinous at first, peridium containing at length
      a dusty mass of threads and spores                _Myxogastres._

III. Spores naked, mostly terminal, on inconspicuous
      threads, free or enclosed in a perithecium        CONIOMYCETES.
   Growing on dead or dying plants--
     Subcutaneous--
       Perithecium more or less distinct                _Sphæronemei._
       Perithecium obsolete or wanting                  _Melanconiei._
     Superficial--
       Fructifying surface naked.
         Spores compound or tomiparous                  _Torulacei._
   Parasitic on living plants--
     Peridium distinctly cellular                       _Æcidiacei._
     Peridium none--
       Spores sub-globose, simple or deciduous          _Cæomacei._
       Spores mostly oblong, usually septate            _Pucciniæi._

IV. Spores naked, on conspicuous threads, rarely
     compacted, small                                   HYPHOMYCETES.
   Fertile threads compacted, sometimes cellular--
     Stem or stroma compound--
       Spores dry, volatile                             _Isariacei._
       Mass of spores moist, diffluent                  _Stilbacei._
   Fertile threads, free or anastomosing--
     Fertile threads dark, carbonized--
       Spores mostly compound                           _Dematiei._
     Fertile threads not carbonized--
       Very distinct--
         Spores mostly simple                           _Mucedines._
       Scarcely distinct from mycelium--
         Spores profuse                                 _Sepedoniei._


   DIVISION II.            SPORIDIIFERA.          _Sporidia in Asci._

V. Fertile cells seated on threads, not compacted into
    a hymenium                                          PHYSOMYCETES.
   Threads felted, moniliform--
     Sporangia irregular                                _Antennariei._
   Threads free--
     Sporangia terminal or lateral                      _Mucorini._
   Aquatic                                              _Saprolegniei._

VI. Asci formed from the fertile cells of a hymenium    ASCOMYCETES.
   Asci often evanescent--
     Receptacle clavæform--
       Asci springing from threads                      _Onygenei._
     Perithecia free--
       Asci springing from the base                     _Perisporiacei._
   Asci persistent--
     Perithecia opening by a distinct ostiolum          _Sphæriacei._
     Hard or coriaceous, hymenium at length exposed     _Phacidiacei._
     Hypogæous; hymenium complicated                    _Tuberacei._
     Fleshy, waxy, or tremelloid; hymenium mostly
      exposed                                           _Elvellacei._



IV.

USES.


The rigid utilitarian will hardly be satisfied with the short
catalogue which can be furnished of the uses of fungi. Excepting those
which are employed more or less for human food, very few are of any
practical value in arts or medicine. It is true that imperfect
conditions of fungi exert a very important influence on fermentation,
and thus become useful; but, unfortunately, fungi have the reputation
of being more destructive and offensive than valuable or useful.
Notwithstanding that a large number of species have from time to time
been enumerated as edible, yet those commonly employed and recognized
are very few in number, prejudice in many cases, and fear in others,
militating strongly against additions to the number. In Great Britain
this is especially the case, and however advisable it may be to
exercise great care and caution in experimenting on untried or
doubtful species, it can only be regarded as prejudice which prevents
good, in fact, excellent, esculent species being more extensively
used, instead of allowing them to rot by thousands on the spots where
they have grown. Poisonous species are also plentiful, and no golden
rule can be established by means of which any one may detect at a
glance good from bad, without that kind of knowledge which is applied
to the discrimination of species. Yet, after all, the characters of
half a dozen good esculent fungi are acquired as easily as the
distinctions between half a dozen birds such as any ploughboy can
discriminate.

The common mushroom (_Agaricus campestris_) is the best known
esculent, whether in its uncultivated or in a cultivated state. In
Britain many thousands of people, notably the lower classes, will not
recognize any other as fit for food, whilst in Italy the same classes
have a strong prejudice against this very species.[A] In Vienna, we
found by personal experience that, although many others are eaten, it
is this which has the most universal preference, yet it appears but
sparingly in the markets as compared with others. In Hungary it does
not enjoy by any means so good a reputation. In France and in Germany
it is a common article of consumption. The different varieties found,
as the results of cultivation, present some variation in colour,
scaliness of pileus, and other minor features, whilst remaining true
to the constituent characters of the species. Although it is not our
intention to enumerate here the botanical distinctions of the species
to which we may call attention, yet, as mistakes (sometimes fatal) are
often being recorded, in which other fungi are confounded with this,
we may be permitted a hint or two which should be remembered. The
spores are purple, the gills are at first delicate pink, afterwards
purple; there is a permanent ring or collar round the stem, and it
must _not_ be sought in woods. Many accidents might have been spared
had these facts been remembered.

The meadow mushroom (_Agaricus arvensis_) is common in meadows and
lowland pastures, and is usually of a larger size than the preceding,
with which it agrees in many particulars, and is sent in enormous
quantities to Covent Garden, where it frequently predominates over
_Agaricus campestris_. Some persons prefer this, which has a stronger
flavour, to the ordinary mushroom, and it is the species most commonly
sold in the autumn in the streets of London and provincial towns.
According to Persoon, it is preferred in France; and, in Hungary, it
is considered as a special gift from St. George. It has acquired in
England the name of horse mushroom, from the enormous size it
sometimes attains. Withering mentions a specimen that weighed fourteen
pounds.[B]

One of the commonest (in our experience the _most_ common) of all
edible fungi in the public markets of Vienna is the Hallimasche
(_Agaricus melleus_), which in England enjoys no good reputation for
flavour or quality; indeed, Dr. Badham calls it "nauseous and
disagreeable," and adds that "not to be poisonous is its only
recommendation." In Vienna it is employed chiefly for making sauce;
but we must confess that even in this way, and with a prejudice in
favour of Viennese cookery, our experience of it was not satisfactory.
It is at best a sorry substitute for the mushroom. In the summer and
autumn this is a very common species in large tufts on old stumps. In
similar localities, and also in tufts, but neither so large, nor so
common, _Agaricus fusipes_ is found. It is preferable to the foregoing
as an esculent, and is easily recognized by the spindle-shaped stem.

_Agaricus rubescens_, P., belongs to a very suspicious group of
fungi, in which the cap or pileus is commonly studded or sprinkled
with paler warts, the remains of an investing volva. To this group
the poisonous but splendid fly-agaric (_Agaricus muscarius_)
belongs. Notwithstanding its bad company, this agaric has a good
reputation, especially for making ketchup; and Cordier reports it
as one of the most delicate mushrooms of the Lorraine.[C] Its name
is derived from its tendency to become red when bruised.

The white variety of an allied species (_Agaricus vaginatus_) has been
commended, and Dr. Badham says that it will be found inferior to but
few agarics in flavour.

A scaly-capped fungus (_Agaricus procerus_), with a slender stem,
called sometimes the parasol mushroom, from its habit, is an esteemed
esculent. In Italy and France it is in high request, and is included
in the majority of continental works on the edible fungi.[D] In
Austria, Germany, and Spain, it has special "vulgar" names, and is
eaten in all these countries. It is much more collected in England
than formerly, but deserves to be still better known. When once seen
it can scarcely be confounded with any other British species, save one
of its nearest allies, which partakes of its own good qualities
(_Agaricus rachodes_), though not quite so good.

_Agaricus prunulus_, Scop., and _Agaricus orcella_, Badh., if they be
not forms of the same species (which Dr. Bull contends that they are
not[E]), have also a good reputation as esculents. They are both neat,
white agarics, with a mealy odour, growing respectively in woods and
open glades. _Agaricus nebularis_, Batsch, is a much larger species,
found in woods, often in large gregarious patches amongst dead leaves,
with a smoky mouse-coloured pileus, and profuse white spores. It is
sometimes as much as five or six inches in diameter, with rather a
faint odour and mild taste. On the continent, as well as in Britain,
this is included amongst edible fungi. Still larger and more imposing
is the magnificent white species, _Agaricus maximus_, Fr.,[F] which is
figured by Sowerby,[G] under the name of _Agaricus giganteus_. It will
attain a diameter of fourteen inches, with a stem, two inches thick,
and rather a strong odour.

A spring fungus, the true St. George's mushroom, _Agaricus gambosus_,
Fr., makes its appearance in pastures, usually growing in rings, in
May and June, and is welcome to mycophagists from its early growth,
when esculent species are rare. It is highly esteemed in France and
Italy, so that when dried it will realize as much as from twelve to
fifteen shillings per pound. Guillarmod includes it amongst Swiss
esculents.[H] Professor Buckman says that it is one of the earliest
and best of English mushrooms, and others have endorsed his opinions,
and Dr. Badham in writing of it observes, that small baskets of them,
when they first appear in the spring in Italy, are sent as "presents
to lawyers and fees to medical men."

The closely allied species, _Agaricus albellus_,[I] D.C., has also the
reputation of being edible, but it is so rare in England that this
quality cannot be put to the test. The curious short-stemmed _Agaricus
brevipes_, Bull,[J] has a similar reputation.

Two singularly fragrant species are also included amongst the
esculent. These are _Agaricus fragrans_, Sow., and _Agaricus odorus_,
Bull. Both have a sweet anise-like odour, which is persistent for a
long time. The former is pale tawny-coloured, nearly white, the latter
of a dirty pale green. Both are white-spored, and although somewhat
local, sufficient specimens of _Ag. odorus_ may be collected in the
autumn for domestic use. We have the assurance of one who has often
proved them that they constitute an exquisite dish.

A clear ivory-white fungus, _Agaricus dealbatus_, of which a crisped
variety is occasionally found in great numbers, springing up on old
mushroom beds in dense clusters, is very good eating, but rather
deficient in the delicate aroma of some other species. The typical
form is not uncommon on the ground in fir plantations. A more robust
and larger species, _Agaricus geotrupes_, Bull, found on the borders
of woods, often forming rings, both in this country and in the United
States, as well as on the continent of Europe, is recognized as
esculent.

We may add to these three or four other species, in which the stem is
lateral, and sometimes nearly obsolete. The largest and most common is
the oyster mushroom (_Agaricus ostreatus_, Jacq.[K]), so universally
eaten, that it is included in almost every list and book on edible
fungi; it is the most common species in Transylvania, tons of it
sometimes appearing in the markets. It does not possess that delicate
flavour which is found in many species, and although extolled by some
beyond its merits, it is nevertheless perfectly wholesome, and, when
young and carefully cooked, not to be despised. It must not be
confounded with a very similar species (_Agaricus euosmus_, B.), with
rosy spores, which is unpleasant. _Agaricus tessellatus_, Bull,
_Agaricus pometi_, Fr., _Agaricus glandulosus_, Bull, are all allies
of the foregoing, and recorded as edible in the United States,
although not one of the three has hitherto been recorded as occurring
in Great Britain. To these may also be added the following:--_Agaricus
salignus_,[L] Fr., which is rare in England, but not uncommon abroad
and in the United States. In Austria it is commonly eaten. _Agaricus
ulmarius_,[M] Bull, is common on elm trunks, not only in Britain but
also in North America, and is by some preferred to the oyster
mushroom. An allied species, _Agaricus fossulatus_, Cooke,[N] is found
on the Cabul Hills, where it is collected, dried, and forms an article
of commerce with the plains. Another, but smaller species, is dried in
the air on strings passed through a hole in the short stem (_Agaricus
subocreatus_, Cooke), and sent, it is believed, from China to
Singapore.

The smallest species with which we have any acquaintance, that is
edible, is the "nail fungus" (_Agaricus esculentus_,[O] Jacq.),
scarcely exceeding one inch in diameter of the pileus, with a thin
rooting stem. The taste in British specimens when raw is bitter and
unpleasant, but it is clearly eaten in Austria, as its name testifies,
and elsewhere in Europe. It is found in fir plantations in the spring,
at which season it is collected from the fir woods around and sent to
Vienna, where it is only used for flavouring sauces under the name of
"Nagelschwämme."

Before quitting the group of true agarics, to which all hitherto
enumerated belong, we must mention a few others of less importance,
but which are included amongst those good for food. Foremost of these
is a really splendid orange species (_Agaricus cæsarius_, Scop.[P]),
which belongs to the same subgenus as the very deleterious fly-agaric,
and the scarcely less fatal _Agaricus vernus_, Bull. It is universally
eaten on the continent, but has hitherto never been found in Great
Britain. In the same subgenus, _Agaricus strobiliformis_,[Q] Fr.,
which is rare in this country, and probably also _Agaricus Ceciliæ_,
B. & Br.[R] Besides these, _Agaricus excoriatus_, Schæff., _Agaricus
mastoideus_, Fr., _Agaricus gracilentus_, Kromb., and _Agaricus
holosericeus_, Fr.,[S] all belonging to the same subgenus as the
parasol mushroom, more or less uncommon in England.

Although the larger number of esculent agarics are white-spored, some
few, worthy of note, will be found in the other sections, and notably
amongst these the common mushroom and its congener the meadow, or
horse mushroom. In addition to those already enumerated, might be
included also the _Agaricus pudicus_, Bull, which is certainly
wholesome, as well as its ally, _Agaricus leochromus_, Cooke,[T] both
of which have rusty spores.

The late Dr. Curtis,[U] in a letter to the Rev. M. J. Berkeley,
enumerates several of the fungi which are edible amongst those found
in the United States. Of these, he says, _Agaricus amygdalinus_,
Curt., can scarcely be distinguished when cooked from the common
mushroom. _Agaricus frumentaceus_, Bull, and three allied new species,
peculiar to the United States, are commended. _Agaricus cæspitosus_,
Curt., he says, is found in enormous quantities, a single cluster
containing from fifty to one hundred stems, and might well be deemed a
valuable species in times of scarcity. It would not be highly esteemed
where other and better species can be had, but it is generally
preferred to _Agaricus melleus_, Fr. It is suitable for drying for
winter use. In the same communication, he observes that the imperial
(_Agaricus cæsarius_, Scop.), grows in great quantities in oak
forests, and may be obtained by the cart-load in its season; but to
his taste, and that of his family, it is the most unpalatable of
fungi, nor could he find any of the most passionate mycophagists who
would avow that they liked it. There is a disagreeable saline flavour
that they could not remove nor overlay. In addition to these, the same
authority enumerates _Agaricus russula_, Schæff., _Agaricus
hypopithyus_, Curt., and _Agaricus consociatus_, Curt., the latter two
being confined to the United States; _Agaricus columbetta_, Fr., found
in Britain, but not eaten, as well as _Agaricus radicatus_, Bull.
_Agaricus bombycinus_, Schæff., and _Agaricus speciosus_, Fr., are
found in Britain, but by no means common; _Agaricus squarrosus_,
Mull., has always been regarded with great suspicion in this country,
where it is by no means uncommon; _Agaricus cretaceus_, Fr., and
_Agaricus sylvaticus_, Schæff., are close allies of the common
mushroom.

Dr. Curtis says that hill and plain, mountain and valley, woods,
fields, and pastures, swarm with a profusion of good nutritious fungi,
which are allowed to decay where they spring up, because people do not
know how, or are afraid, to use them. By those of us who know their
use, their value was appreciated, as never before, during the late
war, when other food, especially meat, was scarce and dear. Then such
persons as I have heard express a preference for mushrooms over meat
had generally no need to lack grateful food, as it was easily had for
the gathering, and within easy distance of their homes if living in
the country. Such was not always the case, however. I remember once,
during the gloomy period when there had been a protracted drought, and
fleshy fungi were to be found only in damp shaded woods, and but few
even there, I was unable to find enough of any one species for a meal,
so, gathering of every kind, I brought home thirteen different kinds,
had them all cooked together in one grand _pot pourri_, and made an
excellent supper.

One important use to which several species of fungi can be applied, is
the manufacture of ketchup. For this purpose, not only is the
mushroom, _Agaricus campestris_, and the horse mushroom, _Agaricus
arvensis_, available, but also _Agaricus rubescens_ is declared to be
excellent for the purpose, and a delicious, but pale, extract is to be
obtained from _Marasmius oreades_. Other species, as _Coprinus
comatus_, and _Coprinus atramentarius_, are also available, together
with _Fistulina hepatica_, and _Morchella esculenta_. In some
districts, when mushrooms are scarce, it is stated that almost any
species that will yield a dark juice is without scruple mixed with the
common mushroom, and it should seem without any bad consequence except
the deterioration of the ketchup.[V] There is an extensive manufacture
of ketchup conducted at Lubbenham, near Market Harborough, but the
great difficulty appears to be the prevention of decomposition.
Messrs. Perkins receive tons of mushrooms from every part of the
kingdom, and they find, even in the same species, an immense
difference in the quality and quantity of the produce. The price of
mushrooms varies greatly with the season, ranging between one penny
and sixpence per pound. Messrs. Perkins are very careful in their
selection, but little discrimination is used by country manufacturers
on a small scale, who use such doubtful species as _Agaricus
lacrymabundus_, with _Agaricus spadiceus_, and a host of allied
species, which they characterize as nonpareils and champignons. In the
eastern counties _Agaricus arvensis_ has the preference for ketchup.

The generic distinctions between the genuine Agarics and some of the
allied genera can hardly be appreciated by the non-botanical reader,
but we have nevertheless preferred grouping the edible species
together in a somewhat botanical order; and, pursuing this plan, the
next species will be those of _Coprinus_, in which the gills are
deliquescent after the plant has arrived at maturity. The maned
mushroom (_Coprinus comatus_, Fr.)[W] is the best of edible species in
this group. It is very common here by roadsides and other places, and
whilst still young and cylindrical, and the gills still whitish or
with a roseate tint, it is highly to be commended. Similar, but
perhaps somewhat inferior, is _Coprinus atramentarius_, Fr.,[X]
equally common about old stumps and on the naked soil. Both species
are also found and eaten in the United States.

In _Cortinarius_, the veil is composed of arachnoid threads, and the
spores are rusty. The number of edible species are few. Foremost is
the really handsome _Cortinarius violaeus_, Fr.,[Y] often nearly four
inches in diameter, and of a beautiful violet colour; and the smaller
_Cortinarius castaneus_, Fr.,[Z] scarcely exceeding an inch in
diameter, both being found in woods, and common alike to Britain and
the United States. _Cortinarius cinnamomeus_, Fr., is also a lover of
woods, and in northern latitudes is found inhabiting them everywhere.
It has a cinnamon-coloured pileus, with yellowish flesh, and its odour
and flavour is said to partake of the same spice. In Germany it is
held in high esteem. _Cortinarius emodensis_, B., is eaten in Northern
India.

The small genus _Lepista_ of Smith, (which, however, is not adopted by
Fries in his now edition of the "Epicrisis") includes one esculent
species in _Lepista personata_, the _Agaricus personatus_ of Fries.[a]
It is by no means uncommon in Northern Europe or America, frequently
growing in large rings; the pileus is pallid, and the stem stained
with lilac. Formerly it was said to be sold in Covent Garden Market
under the name of "blewits," but we have failed to see or hear of it
during many years in London.

Small fungi of ivory-whiteness are very common amongst grass on lawns
in autumn. These are chiefly _Hygrophorus virgineus_, Fr.,[b] and
although not much exceeding an inch in diameter, with a short stem,
and wide decurrent gills, they are so plentiful in season that
quantity soon compensates for the small size. Except that it is
occasionally eaten in France, it does not enjoy much reputation
abroad. A larger species, varying from buff to orange, _Hygrophorus
pratensis_, Fr.,[c] is scarcely less common in open pastures. This is
very gregarious in habit, often growing in tufts, or portions of
rings. The pileus is fleshy in the centre, and the gills thick and
decurrent. In France, Germany, Bohemia, and Denmark, it is included
with esculent species. In addition may be mentioned _Hygrophorus
eburneus_, Fr., another white species, as also _Hygrophorus niveus_,
Fr., which grows in mossy pastures. _Paxillus involutus_, Fr.,[d]
though very common in Europe, is not eaten, yet it is included by Dr.
Curtis with the esculent species of the United States.

The milky agarics, belonging to the genus _Lactarius_, are distinguished
by the milky juice which is exuded when they are wounded. The spores
are more or less globose, and rough or echinulate, at least in many
species. The most notable esculent is _Lactarius deliciosus_, Fr.,[e] in
which the milk is at first saffron-red, and afterwards greenish, the
plant assuming a lurid greenish hue wherever bruised or broken.
Universal commendation seems to fall upon this species, writers
vying with each other to say the best in its praise, and mycophagists
everywhere endorsing the assumption of its name, declaring it to be
delicious. It is found in the markets of Paris, Berlin, Prague, and
Vienna, as we are informed, and in Sweden, Denmark, Switzerland,
Russia, Belgium; in fact, in nearly all countries in Europe it is
esteemed.

Another esculent species, _Lactarius volemum_, Fr.,[f] has white milk,
which is mild to the taste, whilst in deleterious species with white
milk it is pungent and acrid. This species has been celebrated from
early times, and is said to resemble lamb's kidney.

_Lactarius piperatus_, Fr., is classed in England with dangerous,
sometimes poisonous species, whereas the late Dr. Curtis, of North
Carolina, has distinctly informed us that it is cooked and eaten
in the United States, and that he has partaken of it. He includes
_Lactarius insulsus_, Fr., and _Lactarius subdulcis_, Fr.,[g]
amongst esculent species; both are also found in this country, but
not reputed as edible; and _Lactarius angustissimus_, Lasch, which
is not British. Species of _Lactarius_ seem to be eaten almost
indiscriminately in Russia when preserved in vinegar and salt, in
which condition they form an important item in the kinds of food
allowed in their long fasts, some _Boleti_ in the dried state
entering into the same category.

The species of _Russula_ in many respects resemble _Lactarii_ without
milk. Some of them are dangerous, and others esculent. Amongst the
latter may be enumerated _Russula heterophylla_, Fr., which is very
common in woods. Vittadini pronounces it unsurpassed for fineness of
flavour by even the notable _Amanita cæsarea_.[h] Roques gives also an
account in its favour as consumed in France. Both these authors give
favourable accounts of _Russula virescens_, P.,[i] which the peasants
about Milan are in the habit of putting over wood embers to toast, and
eating afterwards with a little salt. Unfortunately it is by no means
common in England. A third species of _Russula_, with buff-yellow
gills, is _Russula alutacea_, Fr., which is by no means to be
despised, notwithstanding that Dr. Badham has placed it amongst
species to be avoided. Three or four others have also the merit of
being harmless, and these recorded as esculent by some one or more
mycological authors: _Russula lactea_, Fr., a white species, found
also in the United States; _Russula lepida_, Fr., a roseate species,
found also in lower Carolina, U.S.; and another reddish species,
_Russula vesca_, Fr., as well as _Russula decolorans_, Fr. Whilst
writing of this genus, we may observe, by way of caution, that it
includes also one very noxious red species, _Russula emetica_, Fr.,
with white gills, with which some of the foregoing might be confounded
by inexperienced persons.

The chantarelle _Cantharellus cibarius_, Fr., has a most charming and
enticing appearance and odour. In colour, it is of a bright golden
yellow, and its smell has been compared to that of ripe apricots. It
is almost universally eaten in all countries where it is found,
England excepted, where it is only to be met with at the "Freemason's
Tavern" on state occasions, and at the tables of pertinacious
mycophagists.[j] Trattinnick says: "Not only this same fungus never
did any one harm, but might even restore the dead."[k]

The fairy-ring champignon _Marasmius oreades_, Fr., though small, is
plentiful, and one of the most delicious of edible fungi. It grows in
exposed pastures, forming rings, or parts of rings. This champignon
possesses the advantage of drying readily, and preserving its aroma
for a long time. We have often regretted that no persistent attempts
and experiments have been made with the view of cultivating this
excellent and useful species. _Marasmius scorodonius_, Fr.,[l] a
small, strong-scented, and in all respects inferior species, found on
heaths and dry pastures, extending even to the United States, is
consumed in Germany, Austria, and other continental countries, where,
perhaps its garlic odour has been one of its recommendations as an
ingredient in sauces. In this enumeration we have not exhausted all
the gill-bearing species which might be eaten, having included only
those which have some reputation as esculents, and of these more
particularly those found in Great Britain and the United States.

Amongst the _Polyporei_, in which the gill plates are represented by
pores or tubes, fewer esculent species are to be met with than in the
_Agaricini_, and the majority of these belong to the genus _Boletus_.
Whilst in Vienna and Hanover, we were rather surprised to find
_Boletus edulis_, Fr., cut into thin slices and dried, exposed for
sale in almost every shop where meal, peas, and other farinaceous
edibles were sold. This species is common enough in England, but as a
rule it does not seem to please the English palate, whereas on the
continent no fungus is more commonly eaten. This is believed to be the
suillus eaten by the ancient Romans,[m] who obtained it from Bithynia.
The modern Italians dry them on strings for winter use, and in
Hungary a soup is made from them when fresh. A more excellent species,
according to our judgment, is _Boletus æstivalis_, Fr.,[n] which
appears in early summer, and has a peculiar nutty flavour when raw,
reminding one more of a fresh mushroom. _Boletus scaber_, Fr.,[o] is
also common in Britain, as well as the continent, but does not enjoy
so good a reputation as _B. edulis_. Krombholz says that _Boletus
bovinus_, Fr., a gregarious species, found on heaths and in fir woods,
is much sought after abroad as a dish, and is good when dried.
_Boletus castaneus_, Fr.,[p] is a small species with a mild, pleasant
taste when raw, and very good when properly cooked. It is not
uncommonly eaten on the continent. _Boletus chrysenteron_, Fr.,[q] and
_Boletus subtomentosus_, Fr., are said to be very poor eating, and
some authors have considered them injurious; but Mr. W. G. Smith
states that he has on more than one occasion eaten the former, and
Trattinnick states that the latter is eaten in Germany. The late Mr.
Salter informed us that, when employed on the geological staff, he at
one time lived almost entirely on different species of Boleti, without
using much discrimination. Sir W. C. Trevelyan also informs us that he
has eaten _Boletus luridus_ without any unpleasant consequences, but
we confess that we should be sorry to repeat the experiment. Dr.
Badham remarks that he has eaten _Boletus Grevillei_, B., _Boletus
flavus_, With., and _Boletus granulatus_, L., the latter being
recognized also as edible abroad. Dr. Curtis experimented, in the
United States, on _Boletus collinitus_, and although he professes not
to be particularly fond of the Boleti, he recognizes it as esculent,
and adds that it had been pronounced delicious by some to whom he had
sent it. He also enumerates as edible _Boletus luteus_, Fr., _Boletus
elegans_, Fr., _Boletus flavidus_, Fr., _Boletus versipellis_, Fr.,
_Boletus leucomelas_, Tr., and _Boletus ovinus_, Sch. Two Italian
species of _Polyporus_ must not be forgotten. These are _Polyporus
tuberaster_, Pers., which is procured by watering the _pietra
funghaia_, or fungus stone, a kind of tufa, in which the mycelium is
embedded. It is confined to Naples. The other species is _Polyporus
corylinus_, Mauri., procured artificially in Rome from charred stumps
of the cob-nut tree.[r]

Of true _Polyporus_, only two or three species have been regarded
favourably as esculents. These are--_Polyporus intybaceus_, Fr., which
is of very large size, sometimes attaining as much as forty pounds;
_Polyporus giganteus_, Fr., also very large, and leathery when old.
Both these species are natives of Britain. Only young and juicy
specimens must be selected for cooking. _Polyporus umbellatus_, Fr.,
is stated by Fries to be esculent, but it is not found in Britain.
_Polyporus squamosus_, Fr., has been also included; but Mrs. Hussey
thinks that one might as well think of eating saddle-flaps. None of
these receive very much commendation. Dr. Curtis enumerates, amongst
North American species, the _Polyporus cristatus_, Fr., _Polyporus
poripes_, Fr., which, when raw, tastes like the best chestnuts or
filberts, but is rather too dry when cooked. _Polyporus Berkeleii_,
Fr., is intensely pungent when raw, but when young, and before the
pores are visible, it may be eaten with impunity, all its pungency
being dissipated by cooking. _Polyporus confluens_, Fr., he considers
superior, and, in fact, quite a favourite. _Polyporus sulfureus_, Fr.,
which is not eaten in Europe, he considers just tolerably safe, but
not to be coveted. It is by no means to be recommended to persons with
weak stomachs. In his catalogue, Dr. Curtis enumerates one hundred and
eleven species of edible fungi found in Carolina.[s]

With _Fistulina hepatica_, Fr., it is different; for here we encounter
a fleshy, juicy fungus, resembling beefsteak a little in appearance,
and so much more in its uses, that the name of "beefsteak fungus" has
been given to it. Some authors are rapturous in their praise of
_Fistulina_. It sometimes attains a very large size, Dr. Badham
quoting[t] one found by himself nearly five feet in circumference,
and weighing eight pounds; whilst another found by Mr. Graves weighed
nearly thirty pounds. In Vienna it is sliced and eaten with salad,
like beetroot, which it then much resembles. On the continent it is
everywhere included amongst the best of edible species.

The _Hydnei_, instead of pores or tubes, are characterized by spines
or warts, over which the fructifying surface is expanded. The most
common is _Hydnum repandum_, Fr., found in woods and woody places in
England, and on the continent, extending into the United States. When
raw, it is peppery to the taste, but when cooked is much esteemed.
From its drier nature, it can readily be dried for winter use. Less
common in England is _Hydnum imbricatum_, Fr., although not so
uncommon on the continent. It is eaten in Germany, Austria,
Switzerland, France, and elsewhere. _Hydnum lævigatum_, Swartz, is
eaten in Alpine districts.[u] Of the branched species, _Hydnum
coralloides_, Scop.,[v] and _Hydnum Caput Medusæ_, Bull,[w] are
esculent, but very rare in England. The latter is not uncommon in
Austria and Italy, the former in Germany, Switzerland, and France.
_Hydnum erinaceum_, Bull, is eaten in Germany[x] and France.

The Clavarioid fungi are mostly small, but of these the majority of
the white-spored are edible. _Clavaria rugosa_, Bull, is a common
British species, as also is _Clavaria coralloides_, L., the former
being found also in the United States. _Clavaria fastigiata_, D. C.,
is not uncommon; but _Clavaria amethystina_, Bull, a beautiful violet
species, is rare. In France and Italy, _Clavaria cinerea_, Bull, is
classed with esculents; and it is not uncommon in Britain. _Clavaria
botrytis_, P., and _Clavaria aurea_, Schæff., are large and beautiful
species, but rare with us; they extend also into the United States.
Others might be named (Dr. Curtis enumerates thirteen species eaten in
Carolina), which are certainly wholesome, but they are of little
importance as edible species. _Sparassis crispa_, Fr., is, on the
contrary, very large, resembling in size,[y] and somewhat in
appearance, a cauliflower; it has of late years been found several
times in this country. In Austria it is fricasseed with butter and
herbs.

Of the true Tremellæ, none merit insertion here. The curious Jew's ear
(_Hirneola auricula-Judæ_, Fr.), with one or two other species of
_Hirneola_, are collected in great quantities in Tahiti, and shipped
in a dried state to China, where they are used for soup. Some of these
find their way to Singapore.

The false truffles (_Hypogæi_) are of doubtful value, one species
(_Melanogaster variegatus_, Tul.) having formerly been sold in the
markets of Bath as a substitute for the genuine truffle.[z] Neither
amongst the _Phalloidei_ do we meet with species of any economic
value. The gelatinous volva of a species of _Ileodictyon_ is eaten by
the New Zealanders, to whom it is known as thunder dirt; whilst that
of _Phallus Mokusin_ is applied to a like purpose in China;[AA] but
these examples would not lead us to recommend a similar use for
_Phallus impudicus_, Fr., in Britain, or induce us to prove the
assertion of a Scotch friend that the porous stem is very good
eating.

One species of puff-ball, _Lycoperdon giganteum_, Fr,[AB] has many
staunch advocates, and whilst young and cream-like, it is, when well
manipulated, an excellent addition to the breakfast-table. A decided
advantage is possessed by this species, since one specimen is often
found large enough to satisfy the appetites of ten or twelve persons.
Other species of _Lycoperdon_ have been eaten when young, and we have
been assured by those who have made the experiment, that they are
scarcely inferior to their larger congener. _Bovista nigrescens_, Fr.,
and _Bovista plumbea_, Fr., are also eaten in the United States. More
than one species of _Lycoperdon_ and _Bovista_ appear in the bazaars
of India, as at Secunderabad and Rangoon; while the white ant-hills,
together with an excellent Agaric, produce one or more species of
_Podaxon_ which are esculent when young. A species of _Scleroderma_
which grows abundantly in sandy districts, is substituted for truffles
in Perigord pies, of which, however, it does not possess any of the
aroma.

[Illustration: FIG. 43.--_Morchella gigaspora_, from Kashmir.]

Passing over the rest of the sporiferous fungi, we find amongst the
_Ascomycetous_ group several that are highly esteemed. Amongst these
may first be named the species of morel, which are regarded as
delicacies wherever they are found. _Morchella esculenta_, Pers., is
the most common species, but we have also _Morchella semilibera_, D.
C., and the much larger _Morchella crassipes_, Pers. Probably all the
species of _Morchella_ are esculent, and we know that many besides the
above are eaten in Europe and other places; _Morchella deliciosa_,
Fr., in Java; _Morchella bohemica_, Kromb., in Bohemia; _Morchella
gigaspora_, Cooke, and _Morchella deliciosa_, Fr., in Kashmere.[AC]
_Morchella rimosipes_, D. C., occurs in France and Bohemia;
_Morchella Caroliniana_, Bosc., in the Southern United States of
America. W. G. Smith records the occurrence in Britain of specimens of
_Morchella crassipes_, P., ten inches in height, and one specimen was
eleven inches high, with a diameter of seven and a half inches.[AD]

Similar in uses, though differing in appearance, are the species of
_Helvella_, of which several are edible. In both these genera, the
individuals can be dried so readily that they are the more valuable on
that account, as they can be used for flavouring in winter when fresh
specimens of any kind of fungus are difficult to procure. The most
common English species is _Helvella crispa_, Fr., but _Helvella
lacunosa_, Fr., is declared to be equally good, though not so large
and somewhat rare. _Helvella infula_, Fr., is also a large species,
but is not British, although it extends to North America, as also does
_Helvella sulcata_, Afz. Intermediate between the morel and _Helvella_
is the species which was formerly included with the latter, but now
known as _Gyromitra esculenta_, Fr.[AE] It is rarely found in Great
Britain, but is more common on the continent, where it is held in
esteem. A curious stipitate fungus, with a pileus like a hood, called
_Verpa digitaliformis_, Pers.,[AF] is uncommon in England, but
Vittadini states that it is sold in the Italian markets, although only
to be recommended when no other esculent fungus offers, which is
sometimes the case in spring.[AG]

Two or three species of _Peziza_ have the reputation of being
esculent, but they are of very little value; one of these is _Peziza
acetabulum_, L., another is _Peziza cochleata_, Huds., and a third is
_Peziza venosa_, Pers.[AH] The latter has the most decided nitrous
odour, and also fungoid flavour, whilst the former seem to have but
little to recommend them; we have seen whole baskets full of _Peziza
cochleata_ gathered in Northamptonshire as a substitute for morels.

A very interesting genus of edible fungi, growing on evergreen
beech trees in South America, has been named _Cyttaria_. One of
these, _Cyttaria Darwinii_, B., occurs in Terra del Fuego, where it
was found by Mr. C. Darwin[AI] growing in vast numbers, and
forming a very essential article of food for the natives. Another is
_Cyttaria Berteroi_, B., also seen by Mr. Darwin in Chili, and eaten
occasionally, but apparently not so good as the preceding.[AJ] Another
species is _Cyttaria Gunnii_, B., which abounds in Tasmania, and is
held in repute amongst the settlers for its esculent properties.[AK]

[Illustration: FIG. 44.--_Cyttaria Gunnii_, B.]

It remains for us only to note the subterranean fungi, of which the
truffle is the type, to complete our enumeration of esculent species.
The truffle which is consumed in England is _Tuber æstivum_, Vitt.;
but in France the more highly-flavoured _Tuber melanospermum_,
Vitt.,[AL] and also _Tuber magnatum_, Pico, with some other species.
In Italy they are very common, whilst some are found in Algeria. One
species at least is recorded in the North-west of India, but in
Northern Europe and North America they appear to be rare, and
_Terfezia Leonis_ is used as an esculent in Damascus. A large species
of _Mylitta_, sometimes several inches in diameter, occurs plentifully
in some parts of Australia. Although often included with fungi, the
curious production known under the name of _Pachyma cocos_, Fr., is
not a fungus, as proved by the examinations made by the Rev. M. J.
Berkeley. It is eaten under the name of "Tuckahoe" in the United
States, and as it consists almost entirely of pectic acid, it is
sometimes used in the manufacture of jelly.

In the Neilgherries (S. India), a substance is occasionally found
which is allied to the native bread of southern latitudes. It is found
at an elevation of 5,000 feet. The natives call it "a little man's
bread," in allusion to the tradition that the Neilgherries were once
peopled by a race of dwarfs.[AM] At first it was supposed that these
were the bulbs of some orchid, but later another view was held of
their character. Mr. Scott, who examined the specimens sent down to
him, remarks that, instead of being the product of orchids, it is that
of an underground fungus of the genus _Mylitta_. It indeed seems, he
says, very closely allied to, if really distinct from, the so-called
native bread of Tasmania.[AN]

Of the fungi employed in medicine, the first place must be assigned to
ergot, which is the sclerotioid condition of a species of _Claviceps_.
It occurs not only on rye but on wheat, and many of the wild grasses.
On account of its active principle, this fungus still holds its place
in the Materia Medica. Others which formerly had a reputation are now
discarded, as, for instance, the species of _Elaphomyces_; and
_Polyporus officinalis_, Fr., which has been partly superseded as a
styptic by other substances, was formerly employed as a purgative. The
ripe spongy capillitium of the great puff-ball _Lycoperdon giganteum_,
Fr., has been used for similar purposes, and also recommended as an
anodyne; indeed formidable surgical operations have been performed
under its influence, and it is frequently used as a narcotic in the
taking of honey. Langsdorf gives a curious account of its employment
as a narcotic; and in a recent work on Kamtschatka it is said to
obtain a very high price in that country. Dr. Porter Smith writes of
its employment medicinally by the Chinese, but from his own specimens
it is clearly a species of _Polysaccum_, which he has mistaken for
_Lycoperdon_. In China several species are supposed to possess great
virtue, notably the _Torrubia sinensis_, Tul.,[AO] which is developed
on dead caterpillars; as it is, however, recommended to administer it
as a stuffing to roast duck, we may be sceptical as to its own
sanitary qualities. _Geaster hygrometricus_, Fr., we have also
detected amongst Chinese drugs, as also a species of _Polysaccum_, and
the small hard _Mylitta lapidescens_, Horn. In India, a large but
imperfect fungus, named provisionally _Sclerotium stipitatum_, Curr.,
found in nests of the white ant, is supposed to possess great
medicinal virtues.[AP] A species of _Polyporus_ (_P. anthelminticus_,
B.), which grows at the root of old bamboos, is employed in Burmah as
an anthelmintic.[AQ] In former times the Jew's ear (_Hirneola auricula
Judæ_, Fr.) was supposed to possess great virtues, which are now
discredited. Yeast is still included amongst pharmaceutical
substances, but could doubtless be very well dispensed with. Truffles
are no longer regarded as aphrodisiacs.

For other uses, we can only allude to amadou, or German tinder, which
is prepared in Northern Europe from _Polyporus fomentarius_, Fr., cut
in slices, dried, and beaten until it is soft. This substance, besides
being used as tinder, is made into warm caps, chest protectors, and
other articles. This same, or an allied species of _Polyporus_,
probably _P. igniarius_, Fr., is dried and pounded as an ingredient in
snuff by the Ostyacks on the Obi. In Bohemia some of the large
Polyporei, such as _P. igniarius_ and _P. fomentarius_, have the pores
and part of the inner substance removed, and then the pileus is
fastened in an inverted position to the wall, by the part where
originally it adhered to the wood. The cavity is then filled with
mould, and the fungus is used, with good effect, instead of
flower-pots, for the cultivation of such creeping plants as require
but little moisture.[AR]

The barren mycelioid condition of _Penicillium crustaceum_, Fr., is
employed in country districts for the domestic manufacture of vinegar
from saccharine liquor, under the name of the "vinegar plant." It is
stated that _Polysaccum crassipes_, D. C.,[AS] is employed in the
South of Europe to produce a yellow dye; whilst recently _Polyporus
sulfureus_, Fr., has been recommended for a similar purpose. _Agaricus
muscarius_, Fr., the fly-agaric, known to be an active poison, is used
in decoction in some parts of Europe for the destruction of flies and
bugs. Probably _Helotium æruginosum_, Fr.,[AT] deserves mention here,
because it stains the wood on which it grows, by means of its diffuse
mycelium, of a beautiful green tint, and the wood thus stained is
employed for its colour in the manufacture of Tonbridge ware.

This completes the list, certainly of the most important, of the fungi
which are of any direct use to humanity as food, medicine, or in the
arts. As compared with lichens, the advantage is certainly in favour
of fungi; and even when compared with algæ, the balance appears in
their favour. In fact, it may be questioned whether, after all, fungi
do not present a larger proportion of really useful species than any
other of the cryptogams; and without any desire to disparage the
elegance of ferns, the delicacy of mosses, the brilliancy of some
algæ, or the interest which attaches to lichens, it may be claimed for
fungi that in real utility (not uncombined with injuries as real) they
stand at the head of the cryptogams, and in closest alliance with the
flowering plants.

   [A] Badham, Dr. C. D., "A Treatise on the Esculent Funguses of
       England," 1st edition (1847), p. 81, pl. 4; 2nd edition, edited
       by F. Currey, M.A. (1863), p. 94, pl. 4; Cooke, M. C., "A Plain
       and Easy Account of British Fungi," 1st edition (1862), p. 44.

   [B] Mr. Worthington Smith has published, on two sheets, coloured
       figures of the most common esculent and poisonous fungi
       (London, Hardwicke), which will be found more useful than mere
       description in the discrimination of the species.

   [C] Roques, J., "Hist. des Champignons Comestibles et Vénéneux,"
       Paris (1832), p. 130.

   [D] Lenz, Dr. H. 0., "Die Nützlichen und Schädlichen Schwämme," Gotha
       (1831), p. 32, pl. 2.

   [E] Bull, H. G., in "Transactions of Woolhope Club" (1869). Fries
       admits them as distinct species in the new edition of his
       "Epicrisis."

   [F] Hussey's "Illustrations of Mycology," ser. i. pl. 79.

   [G] Sowerby's "British Fungi," pl. 244.

   [H] Favre-Guillarmod, "Les Champignons Comestibles du Canton de
       Neuchatel" (1861), p. 27.

   [I] Sowerby, "English Fungi," pl. 122; Smith, in "Seemann's Journ.
       Bot." (1866), t. 46, f. 45.

   [J] Klotsch, "Flora Borussica," t. 374; Smith, in "Seem. Journ. Bot."
       (1869), t. 95, f. 1-4.

   [K] Krombholz, "Abbildungen der Schwämme," pl. 41, f. 1-7.

   [L] Tratinnick, L., "Fungi Austriaci," p. 47, pl. 4, f. 8.

   [M] Vittadini, "Fungi Mangerecci," pl. 23.

   [N] Cooke, in "Journal of Botany," vol. viii. p. 352.

   [O] Cooke, M. C., "A Plain and Easy Guide," &c., p. 38, pl. 6, fig.
       1.

   [P] Krombholz, "Schwämme," t. 8. Vittadini, "Mang." t. 1.

   [Q] Vittadini, "Mangerecci," t. 9.

   [R] Berkeley, "Outlines," pl. 3, fig. 5.

   [S] Saunders and Smith, "Mycological Illustr." pl. 23.

   [T] Cooke, M. C., "Handbook of British Fungi," vol. i. pl. 1, fig.
       2.

   [U] "Gardener's Chronicle" (1869), p. 1066.

   [V] Berkeley, "Outlines of British Fungology," p. 64.

   [W] Cooke, "Easy Guide to British Fungi," pl. 11.

   [X] Ibid., pl. 12.

   [Y] Hussey, "Mycol. Illust." pl. 12.

   [Z] Bulliard, "Champ." t. 268.

   [a] Cooke, "Easy Guide," pl. 4, fig. 1; Hussey, "Illust." vol. ii.
       pl. 40.

   [b] Greville, "Scot. Crypt. Flora," t. 166.

   [c] Ibid., t. 91.

   [d] Sowerby, "Fungi," pl. 56; Schæffer, "Icones Bav." t. 72.

   [e] Trattinnick, L., "Die Essbaren Schwämme" (1809), p. 82, pl. M;
       Barla, J. B., "Champignons de la Nice" (1859), p. 34, pl. 19.

   [f] Smith, "Edible Mushrooms," fig. 26.

   [g] Barla, "Champ. Nice," t. 20, f. 4-10.

   [h] Vittadini, C., "Funghi Mangerecci" (1835), p. 209; Barla, "Champ.
       Nice," pl. i.

   [i] Vittadini, C., "Funghi Mangerecci," p. 245; Roques, "Champ.
       Comest." p. 86.

   [j] Badham, Dr., "Esculent Funguses of Britain," 2nd ed. p. 110;
       Hussey, "Illust. Brit. Mycol." 1st ser. pl. 4; Barla, "Champ."
       pl. 28, f. 7-15.

   [k] Trattinnick, L., "Essbaren Schwämme," p. 98.

   [l] Lenz, "Die Nützlichen und Schädlichen Schwämme," p. 49.

   [m] Badham, "Esculent Funguses of Great Britain," 2 ed. p. 91.

   [n] Hussey, "Myc. Illus." ii. pl. 25; Paulet, "Champ." t. 170.

   [o] Barla, J. B., "Champ. de la Nice," p. 71, pl. 35, f. 1-5.

   [p] Hussey, "Illustr." ii. t. 17; Barla, "Champ. Nice," t. 32, f.
       11-15.

   [q] Hussey, "Illustr." i. t. 5; Krombholz, "Schwämme," t. 76.

   [r] Badham's "Esculent Funguses," 1st ed. pp. 116 and 120.

   [s] Catalogue of Plants of Carolina, U.S.

   [t] Badham, Dr., "Esculent Funguses," 2nd ed. p. 128; Hussey,
       "Illustrations," 1st ser. pl. 65; Berkeley, in "Gard. Chron."
       (1861), p. 121; Bull, in "Trans. Woolhope Club" (1869).

   [u] Barla, "Champ. Nice," p. 79, pl. 38, f. 5, 6.

   [v] Roques, I. c. p. 48.

   [w] Lenz, p. 93; Roques, I. c. p. 47, pl. 2, fig. 5.

   [x] Lenz, H. O., "Die Nützlichen und Schädlichen Schwämme," p. 93.

   [y] Berkeley, M. J., in "Intellectual Observer," No. 25, pl. 1.

   [z] Berkeley, M. J., "Outlines of British Fungology," p. 293.

  [AA] Berkeley, M. J., "Introduction to Crypt. Bot." p. 347.

  [AB] Cooke, M. C., "A Plain and Easy Guide," &c., p. 96.

  [AC] Cooke, M. C., "On Kashmir Morels," in "Trans. Bot. Soc. Edin."
       vol. x. p. 439, with figs.

  [AD] Smith, "Journ. Bot." vol. ix. p. 214.

  [AE] Cooke, "Handbook," fig. 322.

  [AF] Cooke, "Handbook," fig. 324.

  [AG] Vittadini, C., "Funghi Mangerecci," p. 117.

  [AH] Greville, "Sc. Crypt. Fl." pl. 156.

  [AI] Berkeley, in "Linn Trans." xix. p. 37; Cooke, in "Technologist"
       (1864), p. 387.

  [AJ] Berkeley, M. J., in "Linn. Trans." xix. p. 37.

  [AK] Berkeley, M. J., in "Hooker, Flora Antarctica," p. 147; in
       "Hooker's Journ. Bot." (1848), 576, t. 20, 21.

  [AL] Vittadini, C., "Monographia Tuberacearum" (1831), pp. 36, &c.

  [AM] "Proceedings Agri. Hort. Soc. India" (Dec. 1871), p. lxxix.

  [AN] _Ibid._ (June, 1872), p. xxiii.

  [AO] Lindley, "Vegetable Kingdom," fig. xxiv.

  [AP] Currey, F., in "Linn. Trans." vol. xxiii. p. 93.

  [AQ] "Pharmacopoeia of India," p. 258.

  [AR] "Gard. Chron." (1862), p. 21.

  [AS] Barla, "Champ. de la Nice," p. 126, pl. 47, fig. 11.

  [AT] Greville, "Scott. Crypt. Flora," pl. 241.



V.

NOTABLE PHENOMENA.


There are no phenomena associated with fungi that are of greater
interest than those which relate to luminosity. The fact that fungi
under some conditions are luminous has long been known, since
schoolboys in our juvenile days were in the habit of secreting
fragments of rotten wood penetrated by mycelium, in order to exhibit
their luminous properties in the dark, and thus astonish their more
ignorant or incredulous fellows Rumphius noted its appearance in
Amboyna, and Fries, in his Observations, gives the name of _Thelephora
phosphorea_ to a species of _Corticium_ now known as _Corticium
cæruleum_, on account of its phosphorescence under certain conditions.
The same species is the _Auricularia phosphorea_ of Sowerby, but he
makes no note of its phosphorescence. Luminosity in fungi "has been
observed in various parts of the world, and where the species has been
fully developed it has been generally a species of _Agaricus_ which
has yielded the phenomenon."[A] One of the best-known species is the
_Agaricus olearius_ of the South of Europe, which was examined by
Tulasne with especial view to its luminosity.[B] In his introductory
remarks, he says that four species only of Agaricus that are luminous
appear at present to be known. One of them, _A. olearius_, D. C., is
indigenous to Central Europe; another, _A. igneus_, Rumph., comes from
Amboyna; the third, _A. noctileucus_, Lév., has been discovered at
Manilla by Gaudichaud, in 1836; the last, _A. Gardneri_, Berk., is
produced in the Brazilian province of Goyaz, upon dead leaves. As to
the _Dematium violaceum_, Pers., the _Himantia candida_, Pers., cited
once by Link, and the _Thelephora cærulea_, D. C. _(Corticium
cæruleum_, Fr.), Tulasne is of opinion that their phosphorescent
properties are still problematical; at least no recent observation
confirms them.

The phosphorescence of _A. olearius_, D. C., appears to have been
first made known by De Candolle, but it seems that he was in error in
stating that these phosphorescent properties manifest themselves only
at the time of its decomposition. Fries, describing the _Cladosporium
umbrinum_, which lives upon the Agaric of the olive-tree, expressed
the opinion that the Agaric only owes its phosphorescence to the
presence of the mould. This, however, Tulasne denies, for he writes,
"I have had the opportunity of observing that the Agaric of the olive
is really phosphorescent of itself, and that it is not indebted to any
foreign production for the light it emits." Like Delile, he considers
that the fungus is only phosphorescent up to the time when it ceases
to grow; thus the light which it projects, one might say, is a
manifestation of its vegetation.

"It is an important fact," writes Tulasne, "which I can confirm, and
which it is important to insist upon, that the phosphorescence is not
exclusively confined to the hymenial surface. Numerous observations
made by me prove that the whole of the substance of the fungus
participates very frequently, if not always, in the faculty of shining
in the dark. Among the first Agarics which I examined, I found many,
the stipe of which shed here and there a light as brilliant as the
hymenium, and led me to think that it was due to the spores which had
fallen on the surface of the stipe. Therefore, being in the dark, I
scraped with my scalpel the luminous parts of the stipe, but it did
not sensibly diminish their brightness; then I split the stipe,
bruised it, divided it into small fragments, and I found that the
whole of this mass, even in its deepest parts, enjoyed, in a similar
degree to its superficies, the property of light. I found, besides, a
phosphorescence quite as brilliant in all the cap, for, having split
it vertically in the form of plates, I found that the trama, when
bruised, threw out a light equal to that of their fructiferous
surfaces, and there is really only the superior surface of the pileus,
or its cuticle, which I have never seen luminous.

"As I have said, the Agaric of the olive-tree, which is itself
very yellow, reflects a strong brilliant light, and remains
endowed with this remarkable faculty whilst it grows, or, at
least, while it appears to preserve an active life, and remains fresh.
The phosphorescence is at first, and more ordinarily, recognizable
at the surface of the hymenium. I have seen a great number of young
fungi which were very phosphorescent in the gills, but not in any
other part. In another case, and amongst more aged fungi, the
hymenium of which had ceased to give light, the stipe, on the
contrary, threw out a brilliant glare. Habitually, the phosphorescence
is distributed in an unequal manner upon the stipe, and the same
upon the gills. Although the stipe is luminous at its surface, it is
not always necessarily so in its interior substance, if one bruises
it, but this substance frequently becomes phosphorescent after
contact with the air. Thus, I had irregularly split and slit a large
stipe in its length, and I found the whole flesh obscure, whilst
on the exterior were some luminous places. I roughly joined the
lacerated parts, and the following evening, on observing them
anew, I found them all flashing a bright light. At another time, I
had with a scalpel split vertically many fungi in order to hasten
their dessication; the evening of the same day, the surface of all
these cuts was phosphorescent, but in many of these pieces of fungi
the luminosity was limited to the cut surface which remained
exposed to the air; the flesh beneath was unchanged.

"I have seen a stipe opened and lacerated irregularly, the whole of
the flesh of which remained phosphorescent during three consecutive
evenings, but the brightness diminished in intensity from the exterior
to the interior, so that on the third day it did not issue from the
inner part of the stipe. The phosphorescence of the gills is in no way
modified at first by immersing the fungus in water; when they have
been immersed they are as bright as in the air, but the fungi which I
left immersed until the next evening lost all their phosphorescence,
and communicated to the water an already sensible yellow tint; alcohol
put upon the phosphorescent gills did not at once completely
obliterate the light, but visibly enfeebled it. As to the spores,
which are white, I have found many times very dense coats of them
thrown down on porcelain plates, but I have never seen them
phosphorescent.

"As to the observation made by Delile that the Agaric of the olive
does not shine during the day when placed in total darkness, I think
that it could not have been repeated. From what I have said of the
phosphorescence of _A. olearius_, one naturally concludes that there
does not exist any necessary relation between this phenomenon and the
fructification of the fungus; the luminous brightness of the hymenium
shows, says Delile, 'the greater activity of the reproductive organs,'
but it is not in consequence of its reproductive functions, which may
be judged only as an accessory phenomenon, the cause of which is
independent of, and more general than these functions, since all the
parts of the fungus, its entire substance, throws forth at one time,
or at successive times, light. From these experiments Tulasne infers
that the same agents, oxygen, water, and warmth, are perfectly
necessary to the production of phosphorescence as much in living
organized beings as in those which have ceased to live. In either
case, the luminous phenomena accompany a chemical reaction which
consists principally in a combination of the organized matter with the
oxygen of the air; that is to say, in its combustion, and in the
discharge of carbonic acid which thus shows itself."

We have quoted at considerable length from these observations of
Tulasne on the Agaric of the olive, as they serve very much to
illustrate similar manifestations in other species, which doubtless
resemble each other in their main features.

Mr. Gardner has graphically described his first acquaintance in Brazil
with the phosphorescent species which now bears his name. It was
encountered on a dark night of December, while passing through the
streets of Villa de Natividate. Some boys were amusing themselves
with some luminous object, which at first he supposed to be a kind of
large fire-fly, but on making inquiry he found it to be a beautiful
phosphorescent Agaric, which he was told grew abundantly in the
neighbourhood on the decaying fronds of a dwarf palm. The whole plant
gives out at night a bright light somewhat similar to that emitted by
the larger fire-flies, having a pale greenish hue. From this
circumstance, and from growing on a palm, it was called by the
inhabitants "flor de coco."[C]

The number of recognized phosphorescent species of _Agaricus_ is not
large, although two or three others may be enumerated in addition to
those cited by Tulasne. Of these, _Agaricus lampas_, and some others,
are found in Australia.[D] In addition to the _Agaricus noctileucus_,
discovered by Gaudichaud, and the _Agaricus igneus_ of Rumphius, found
in Amboyna, Dr. Hooker speaks of the phenomenon as common in Sikkim,
but he seems never to have been able to ascertain with what species it
was associated.

Dr. Cuthbert Collingwood has communicated some further information
relative to the luminosity of a species of _Agaricus_ in Borneo
(supposed to be _A. Gardneri_), in which he says, "The night being
dark, the fungi could be very distinctly seen, though not at any great
distance, shining with a soft pale greenish light. Here and there
spots of much more intense light were visible, and these proved to be
very young and minute specimens. The older specimens may more properly
be described as possessing a greenish luminous glow, like the glow of
the electric discharge, which, however, was quite sufficient to define
its shape, and, when closely examined, the chief details of its form
and appearance. The luminosity did not impart itself to the hand, and
did not appear to be affected by the separation from the root on which
it grew, at least not for some hours. I think it probable that the
mycelium of this fungus is also luminous, for, upon turning up the
ground in search of small luminous worms, minute spots of light were
observed, which could not be referred to any particular object or body
when brought to the light and examined, and were probably due to some
minute portions of its mycelium."[E] The same writer also adds, "Mr.
Hugh Low has assured me that he saw the jungle all in a blaze of light
(by which he could see to read) as, some years ago, he was riding
across the island by the jungle road; and that this luminosity was
produced by an Agaric."

Similar experiences were detailed by Mr. James Drummond in a letter
from Swan River, in which two species of Agaric are concerned. They
grew on the stumps of trees, and had nothing remarkable in their
appearance by day, but by night emitted a most curious light, such as
the writer never saw described in any book. One species was found
growing on the stump of a _Banksia_ in Western Australia. The stump
was at the time surrounded by water. It was on a dark night, when
passing, that the curious light was first observed. When the fungus
was laid on a newspaper, it emitted by night a phosphorescent light,
enabling persons to read the words around it, and it continued to do
so for several nights with gradually decreasing intensity as the plant
dried up. In the other instance, which occurred some years after, the
author, during one of his botanical trips, was struck by the
appearance of a large Agaric, measuring sixteen inches in diameter,
and weighing about five pounds. This specimen was hung up to dry in
the sitting-room, and on passing through the apartment in the dark it
was observed to give out the same remarkable light. The luminous
property continued, though gradually diminishing, for four or five
nights, when it ceased on the plant becoming dry. "We called some of
the natives," he adds, "and showed them this fungus when emitting
light, and the poor creatures cried out 'chinga,' their name for a
spirit, and seemed much afraid of it."[F]

Although the examples already cited are those of species of Agaric,
luminosity is not by any means wholly confined to that genus. Mr.
Worthington Smith has recorded his experiences of some specimens of
the common _Polyporus annosus_ which were found on some timbers in the
Cardiff coal mines. He remarks that the colliers are well acquainted
with phosphorescent fungi, and the men state that sufficient light is
given "to see their hands by." The specimens of _Polyporus_ were so
luminous that they could be seen in the dark at a distance of twenty
yards. He observes further, that he has met with specimens of
_Polyporus sulfureus_ which were phosphorescent. Some of the fungi
found in mines, which emit light familiar to the miners, belong to the
incomplete genus _Rhizomorpha_, of which Humboldt amongst others gives
a glowing account. Tulasne has also investigated this phenomenon in
connection with the common _Rhizomorpha subterranea_, Pers. This
species extends underneath the soil in long strings, in the
neighbourhood of old tree stumps, those of the oak especially, which
are becoming rotten, and upon these it is fixed by one of its
branches. These are cylindrical, very flexible, branching, and clothed
with a hard bark, encrusting and fragile, at first smooth and brown,
becoming later very rough and black. The interior tissue, at first
whitish, afterwards of a more or less deep brown colour, is formed of
extremely long parallel filaments from .0035 to .015 _mm._ in
diameter.

On the evening of the day when I received the specimens,[G] he writes,
the temperature being about 22° Cent., all the young branches
brightened with an uniform phosphoric light the whole of their length;
it was the same with the surface of some of the older branches, the
greater number of which were still brilliant in some parts, and only
on their surface. I split and lacerated many of these twigs, but their
internal substance remained dull. The next evening, on the contrary,
this substance, having been exposed to contact with the air, exhibited
at its surface the same brightness as the bark of the branches. I made
this observation upon the old stalks as well as upon the young ones.
Prolonged friction of the luminous surfaces reduced the brightness
and dried them to a certain degree, but did not leave on the fingers
any phosphorescent matter. These parts continued with the same
luminous intensity after holding them in the mouth so as to moisten
them with saliva; plunged into water, held to the flame of a candle so
that the heat they acquired was very appreciable to the touch, they
still emitted in the dark a feeble light; it was the same after being
held in water heated to 30° C.; but putting them in water bearing a
temperature of 55° C. extinguished them entirely. They are equally
extinguished if held in the mouth until they catch the temperature;
perhaps, still, it might be attributed less to the heat which is
communicated to them than to the deficiency of sufficient oxygen,
because I have seen some stalks, having become dull in the mouth,
recover after a few instants a little of their phosphorescence. A
young stalk which had been split lengthwise, and the internal
substance of which was very phosphorescent, could imbibe olive oil
many times and yet continue for a long time to give a feeble light. By
preserving these _Rhizomorphæ_ in an adequate state of humidity, I
have been able for many evenings to renew the examination of their
phosphorescence; the commencement of dessication, long before they
really perish, deprives them of the faculty of giving light. Those
which had been dried for more than a month, when plunged into water,
commenced to vegetate anew and send forth numerous branches in a few
days; but I could only discover phosphorescence at the surface of
these new formations, or very rarely in their immediate neighbourhood,
the mother stalks appearing to have lost by dessication their luminous
properties, and did not recover them on being recalled to life. These
observations prove that what Schmitz has written was not true, that
all parts of these fungi were seldom phosphorescent.

The luminous phenomenon in question is without doubt more complicated
than it appears, and the causes to which we attribute it are certainly
powerfully modified by the general character of the objects in which
they reside. Most of the German botanists give this explanation,
others suppose that it forms at first or during its continuance a
special matter, in which the luminous property resides; this matter,
which is said to be mucilaginous in the luminous wood, appears to be
in the _Rhizomorpha_ only a kind of chemical combination between the
membrane and some gummy substance which they contain. Notwithstanding
this opinion, I am assured that all external mucous matter was
completely absent from the _Agaricus olearius_, and I neither
discovered it upon the branches of _Rhizomorpha subterranea_ nor upon
the dead leaves which I have seen phosphorescent; in all these objects
the luminous surfaces were nothing else than their proper tissue.

It may be remarked here that the so-called species of _Rhizomorpha_
are imperfect fungi, being entirely devoid of fructification,
consisting in fact only of a vegetative system--a sort of compact
mycelium--(probably of species of _Xylaria_) with some affinity to
_Sclerotium_.

Recently an extraordinary instance of luminosity was recorded as
occurring in our own country.[H] "A quantity of wood had been
purchased in a neighbouring parish, which was dragged up a very steep
hill to its destination. Amongst them was a log of larch or spruce, it
is not quite certain which, 24 feet long and a foot in diameter. Some
young friends happened to pass up the hill at night, and were
surprised to find the road scattered with luminous patches, which,
when more closely examined, proved to be portions of bark or little
fragments of wood. Following the track, they came to a blaze of white
light which was perfectly surprising. On examination, it appeared that
the whole of the inside of the bark of the log was covered with a
white byssoid mycelium of a peculiarly strong smell, but unfortunately
in such a state that the perfect form could not be ascertained. This
was luminous, but the light was by no means so bright as in those
parts of the wood where the spawn had penetrated more deeply, and
where it was so intense that the roughest treatment scarcely seemed to
check it. If any attempt was made to rub off the luminous matter it
only shone the more brightly, and when wrapped up in five folds of
paper the light penetrated through all the folds on either side as
brightly as if the specimen was exposed; when, again, the specimens
were placed in the pocket, the pocket when opened was a mass of light.
The luminosity had now been going on for three days. Unfortunately we
did not see it ourselves till the third day, when it had, possibly
from a change in the state of electricity, been somewhat impaired; but
it was still most interesting, and we have merely recorded what we
observed ourselves. It was almost possible to read the time on the
face of a watch even in its less luminous condition. We do not for a
moment suppose that the mycelium is essentially luminous, but are
rather inclined to believe that a peculiar concurrence of climatic
conditions is necessary for the production of the phenomenon, which is
certainly one of great rarity. Observers as we have been of fungi in
their native haunts for fifty years, it has never fallen to our lot to
witness a similar case before, though Prof. Churchill Babington once
sent us specimens of luminous wood, which had, however, lost their
luminosity before they arrived. It should be observed that the parts
of the wood which were most luminous were not only deeply penetrated
by the more delicate parts of the mycelium, but were those which were
most decomposed. It is probable, therefore, that this fact is an
element in the case as well as the presence of fungoid matter."

In all cases of phosphorescence recorded, the light emitted is
described as of the same character, varying only in intensity. It
answers well to the name applied to it, as it seems remarkably similar
to the light emitted by some living insects and other animal
organisms, as well as to that evolved, under favourable conditions, by
dead animal matter--a pale bluish light, resembling that emitted by
phosphorus as seen in a dark room.

Another phenomenon worthy of note is the change of colour which the
bruised or cut surface of some fungi undergo. Most prominent amongst
these are certain poisonous species of _Boletus_, such, for instance,
as _Boletus luridus_, and some others, which, on being bruised, cut,
or divided, exhibit an intense, and in some cases vivid, blue. At
times this change is so instantaneous that before the two freshly-cut
portions of a _Boletus_ can be separated, it has already commenced,
and proceeds rapidly till the depth of intensity has been gained.
This blue colour is so universally confined to dangerous species that
it is given as a caution that all species which exhibit a blue colour
when cut or bruised, should on no account be eaten. The degree of
intensity varies considerably according to the condition of the
species. For example, _Boletus cærulescens_ is sometimes only very
slightly, if at all, tinged with blue when cut, though, as the name
implies, the peculiar phenomenon is generally highly developed. It
cannot be said that this change of colour has as yet been fully
investigated. One writer some time since suggested, if he did not
affirm, that the colour was due to the presence of aniline, others
have contented themselves with the affirmation that it was a rapid
oxidization and chemical change, consequent upon exposure of the
surfaces to the air. Archdeacon Robinson examined this phenomenon in
different gases, and arrived at the conclusion that the change depends
on an alteration of molecular arrangement.[I]

One of the best of the edible species of _Lactarius_, known as
_Lactarius deliciosus_, changes, wherever cut or bruised, to a dull
livid green. This fungus is filled with an orange milky fluid, which
becomes green on exposure to the air, and it is consequently the juice
which oxidizes on exposure. Some varieties more than others of the
cultivated mushroom become brownish on being cut, and a similar change
we have observed, though not recorded, in other species.

The presence of a milky juice in certain fungi has been alluded to.
This is by no means confined to the genus _Lactarius_, in which such
juice is universal, sometimes white, sometimes yellow, and sometimes
colourless. In Agarics, especially in the subgenus _Mycena_, the gills
and stem are replete with a milky juice. Also in some species of
_Peziza_, as for instance in _Peziza succosa_, B., sometimes found
growing on the ground in gardens, and in _Peziza saniosa_, Schrad.,
also a terrestrial species, the same phenomenon occurs. To this might
be added such species as _Stereum spadiceum_, Fr., and _Stereum
sanguinolentum_, Fr., both of which become discoloured and bleeding
when bruised, while _Corticium lactescens_ distils a watery milk.

Fungi in general have not a good repute for pleasant odours, and yet
it must be conceded that they are not by any means devoid of odour,
sometimes peculiar, often strong, and occasionally very offensive.
There is a peculiar odour common to a great many forms, which has come
to be called a fungoid odour; it is the faint smell of a long-closed
damp cellar, an odour of mouldiness and decay, which often arises from
a process of eremocausis. But there are other, stronger, and equally
distinct odours, which, when once inhaled, are never to be forgotten.
Amongst these is the fetid odour of the common stinkhorn, which is
intensified in the more beautiful and curious _Clathrus_. It is very
probable that, after all, the odour of the _Phallus_ would not be so
unpleasant if it were not so strong. It is not difficult to imagine,
when one encounters a slight sniff borne on a passing breeze, that
there is the element of something not by any means unpleasant about
the odour when so diluted; yet it must be confessed that when carried
in a vasculum, in a close carriage, or railway car, or exposed in a
close room, there is no scruple about pronouncing the odour intensely
fetid. The experience of more than one artist, who has attempted the
delineation of _Clathrus_ from the life, is to the effect that the
odour is unbearable even by an enthusiastic artist determined on
making a sketch.

Perhaps one of the most fetid of fungi is _Thelephora palmata_. Some
specimens were on one occasion taken by Mr. Berkeley into his bedroom
at Aboyne, when, after an hour or two, he was horrified at finding the
scent far worse than that of any dissecting room. He was anxious to
save the specimens, but the scent was so powerful that it was quite
intolerable till he had wrapped them in twelve thick folds of the
strongest brown paper. The scent of _Thelephora fastidiosa_ is bad
enough, but, like that of _Coprinus picaceus_, it is probably derived
from the imbibition of the ordure on which it is developed. There
needs no stronger evidence that the scent must not only be powerful,
but unpleasant, when an artist is compelled, before a rough sketch is
more than half finished, to throw it away, and seek relief in the open
air. A great number of edible Agarics have the peculiar odour of
fresh meal, but two species, _Agaricus odorus_ and _Agaricus
fragrans_, have a pleasant anise-like odour. In two or three species
of tough _Hydnum_, there is a strong persistent odour somewhat like
melilot or woodruffe, which does not pass away after the specimen has
been dried for years. In some species of _Marasmius_, there is a
decidedly strong odour of garlic, and in one species of _Hygrophorus_,
such a resemblance to that of the larva of the goat moth, that it
bears the name of _Hygrophorus cossus_. Most of the fleshy forms
exhale a strong nitrous odour during decay, but the most powerful we
remember to have experienced was developed by a very large specimen of
_Choiromyces meandriformis_, a gigantic subterranean species of the
truffle kind, and this specimen was four inches in diameter when
found, and then partially decayed. It was a most peculiar, but strong
and unpleasantly pungent nitrous odour, such as we never remember to
have met with in any other substance. _Peziza venosa_ is remarkable
when fresh for a strong scent like that of aquafortis.

Of colour, fungi exhibit an almost endless variety, from white,
through ochraceous, to all tints of brown until nearly black, or
through sulphury yellow to reds of all shades, deepening into crimson,
or passing by vinous tints into purplish black. These are the
predominating gradations, but there are occasional blues and mineral
greens, passing into olive, but no pure or chlorophyllous green. The
nearest approach to the latter is found in the hymenium of some
_Boleti_. Some of the Agarics exhibit bright colours, but the larger
number of bright-coloured species occur in the genus _Peziza_. Nothing
can be more elegant than the orange cups of _Peziza aurantia_, the
glowing crimson of _Peziza coccinea_, the bright scarlet of _Peziza
rutilans_, the snowy whiteness of _Peziza nivea_, the delicate yellow
of _Peziza theleboloides_, or the velvety brown of _Peziza repanda_.
Amongst Agarics, the most noble _Agaricus muscarius_, with its warty
crimson pileus, is scarcely eclipsed by the continental orange
_Agaricus cæsarius_. The amethystine variety of _Agaricus laccatus_ is
so common and yet so attractive; whilst some forms and species
_Russula_ are gems of brilliant colouring. The golden tufts of more
than one species of _Clavaria_ are exceedingly attractive, and the
delicate pink of immature _Lycogala epidendrum_ is sure to command
admiration. The minute forms which require the microscope, as much to
exhibit their colour as their structure, are not wanting in rich and
delicate tints, so that the colour-student would find much to charm
him, and good practice for his pencil in these much despised examples
of low life.

Amongst phenomena might be cursorily mentioned the peculiar sarcodioid
mycelium of _Myxogastres_, the development of amoeboid forms from
their spores, and the extraordinary rapidity of growth, as the
well-known instance of the _Reticularia_ which Schweinitz observed
running over iron a few hours after it had been red hot. Mr. Berkeley
has observed that the creamy mycelium of _Lycogala_ will not revive
after it has become dry for a few hours, though so active before.

   [A] M. J. Berkeley, "Introduction to Cryptogamic Botany," p. 265.

   [B] Tulasne, "Sur la Phosphorescence des Champignons," in "Ann. des
       Sci. Nat." (1848), vol. ix, p. 338.

   [C] In "Hooker's Journal of Botany" (1840), vol. ii. p. 426.

   [D] Berkeley, "Introduction to Crypt. Bot." t. 265.

   [E] Dr. Collingwood, in "Journal of Linnæan Society (Botany)," vol.
       x. p. 469.

   [F] In "Hooker's Journal of Botany" for April, 1842.

   [G] Tulasne, "Sur la Phosphorescence," in "Ann. des Sci. Nat."
       (1848), vol ix. p. 340, &c.

   [H] Rev. M. J. Berkeley, in "Gardener's Chronicle" for 1872, p.
       1258.

   [I] Berkeley, "Introduction to Crypt. Bot." p. 266.



VI.

THE SPORE AND ITS DISSEMINATION.


A work of this character would hardly be deemed complete without some
reference to the above subject, which has moreover a relation to some
of the questions discussed, and particularly of spore diffusion in the
atmosphere. The largest spore is microscopic, and the smallest known
scarcely visible under a magnifying power of 360 diameters. Taking
into account the large number of species of fungi, probably scarcely
less numerous than all the flowering plants, and the immense number of
spores which some of the individuals produce, they must be exceedingly
plentiful and widely diffused, though from their minuteness not easy
to be discerned. It has been attempted to estimate the number of
spores which might be produced by one single plant of _Lycoperdon_,
but the number so far exceeds that which the mind is accustomed to
contemplate that it seems scarcely possible to realize their
profusion. Recent microscopic examinations of the common atmosphere[A]
show the large quantity of spores that are continually suspended. In
these investigations it was found that spores and similar cells were
of constant occurrence, and were generally present in considerable
numbers. That the majority of the cells were living, and ready to
undergo development on meeting with suitable conditions, was very
manifest, as in those cases in which preparations were retained under
observation for any length of time, germination rapidly took place in
many of the cells. In few instances did any development take place,
beyond the formation of networks of mycelium, or masses of toruloid
cells, but, in one or two, distinct sporules were developed on the
filaments arising from some of the larger septate spores; and in a few
others, _Penicillium_ and _Aspergillus_ produced their characteristic
heads of fructification. With regard to the precise nature of the
spores, and other cells present in various instances, little can be
said, as, unless their development were to be carefully followed out
through all its stages, it is impossible to refer them to their
correct species or even genera. The greater number of them are
apparently referable to the old orders of fungi, _Sphæronemei_,
_Melanconei_, _Torulacei_, _Dematiei_ and _Mucedines_, while some
probably belonged to the _Pucciniæi_ and _Cæomacei_.

Hence it is demonstrated that a large number of the spores of fungi
are constantly present in the atmosphere, which is confirmed by
the fact that whenever a suitable pabulum is exposed it is taken
possession of by floating spores, and soon converted into a forest
of fungoid vegetation. It is admitted that the spores of such
common moulds as _Aspergillus_ and _Penicillium_ are so widely
diffused, that it is almost impossible to exclude them from closed
vessels, or the most carefully guarded preparations. Special
contrivances for the dispersion of the spores in the different groups
follow a few general types, and it is only rarely that we meet with
any method that is confined only to a species or genus. Some of
the more significant forms of spores may be illustrated, with their
modes of dissemination.

BASIDIOSPORES is a term which we may employ here to designate all
spores borne at the tips of such supports as are found in the
_Hymenomycetes_ and _Gasteromycetes_, to which the name of basidia has
been given. In fact, under this section we may include all the spores
of those two orders, although we may be ignorant of the precise mode
in which the fruit of most of the _Myxogastres_ is developed. Guarding
ourselves at the outset against any misinterpretation as to the use of
this term, which, in fact, we employ simply to designate the fruit of
_Hymenomycetes_, we may have excuse in our desire to limit special
terms as much as possible. In the _Agaricini_ the spores are
plentiful, and are distributed over the hymenium or gill plates, the
surface of which is studded with basidia, each of which normally
terminates with four short, erect, delicate, thread-like processes,
each of which is surmounted by a spore. These spores are colourless or
coloured, and it is upon this fact that primary divisions in the genus
_Agaricus_ are based, inasmuch as colour in the spores appears to be a
permanent feature. In white-spored species the spores are white in all
the individuals, not mutable as the colour of the pileus, or the
corolla in phanerogamic plants. So also with the pink spored, rusty
spored, black spored, and others. This may serve to explain why
colour, which is so little relied upon in classification amongst the
higher plants, should be introduced as an element of classification in
one of the largest genera of fungi.

[Illustration: FIG. 45.--Spores of (_a_) _Agaricus mucidus_; (_b_)
_Agaricus vaginatus_; (_c_) _Agaricus pascuus_; (_d_) _Agaricus
nidorosus_; (_e_) _Agaricus campestris_. (Smith.)]

[Illustration: FIG. 46.--Spores of (_a_) _Lactarius blennius_; (_b_)
_Lactarius fuliginosus_; (_c_) _Lactarius quietus_. (Smith.)]

There are considerable differences in size and form amongst the spores
of the _Agaricini_, although at first globose; when mature they are
globose, oval, oblong, elliptic, fusiform, and either smooth or
tuberculated, often maintaining in the different genera or subgenera
one particular characteristic, or typical form. It is unnecessary here
to particularize all the modifications which the form and colour of
the spores undergo in different species, as this has already been
alluded to. The spores in the _Polyporei_, _Hydnei_, &c., are less
variable, of a similar character, as in all the _Hymenomycetes_,
except perhaps the _Tremellini_.

[Illustration: FIG. 46a.--(_a_) Spore of _Gomphidius viscidus;_ (_b_)
spore of _Coprinus micaceus_.]

[Illustration: FIG. 47.--Spores of (_a_) _Polyporus cæsius_; (_b_)
_Boletus parasiticus_; (_c_) _Hydnum_.]

When an Agaric is mature, if the stem is cut off close to the gills,
and the pileus inverted, with the gills downwards on a sheet of black
paper (one of the pale-spored species is best for this purpose), and
left for a few hours, or all night, in that position, the paper will
be found imprinted in the morning with a likeness of the under side of
the pileus with its radiating gills, the spores having been thrown
down upon the paper in such profusion, from the hymenium, and in
greater numbers from the opposed surfaces of the gills. This little
experiment will be instructive in two or three points. It will
illustrate the facility with which the spores are disseminated, the
immense number in which they are produced, and the adaptability of the
gill structure to the economy of space, and the development of the
largest number of basidiospores from a given surface. The tubes or
pores in _Polyporei_, the spines in _Hydnei_, are modifications of the
same principles, producing a like result.

In the _Gasteromycetes_ the spores are produced in many cases, probably
in most, if not all, at the tips of sporophores; but the hymenium,
instead of being exposed, as in the _Hymenomycetes_, is enclosed within
an outer peridium or sac, which is sometimes double. The majority of
these spores are globose in form, some of them extremely minute,
variously coloured, often dark, nearly black, and either externally
smooth or echinulate. In some genera, as _Enerthenema_, _Badhamia_,
&c., a definite number of spores are at first enclosed in delicate
cysts, but these are exceptions to the general rule: this also is the
case in at least one species of _Hymenogaster_. As the spores approach
maturity, it may be observed in such genera as _Stemonitis_, _Arcyria_,
_Diachea_, _Dictydium_, _Cribraria_, _Trichia_, &c., that they are
accompanied by a sort of reticulated skeleton of threads, which
remain permanent, and served in earlier stages, doubtless, as
supports for the spores; being, in fact, the skeleton of the hymenium.
It has been suggested that the spiral character of the threads in
_Trichia_ calls to mind the elaters in the _Hepaticæ_, and like them
may, by elasticity, aid in the dispersion of the spores. There is
nothing known, however, which will warrant this view. When the spores
are mature, the peridium ruptures either by an external orifice, as
in _Geaster_, _Lycoperdon_, &c., or by an irregular opening, and the
light, minute, delicate, spores are disseminated by the slightest
breath of air. Specimens of _Geaster_ and _Bovista_ are easily
separated from the spot on which they grew; when rolling from place
to place, the spores are deposited over a large surface. In the
_Phalloidei_ the spores are involved in a slimy mucus which would
prevent their diffusion in such a manner. This gelatinous substance has
nevertheless a peculiar attraction for insects, and it is not altogether
romantic to believe that in sucking up the fetid slime, they also
imbibe the spores and transfer them from place to place, so that even
amongst fungi insects aid in the dissemination of species. Whether or
not the _Myxogastres_ should be included here is matter of opinion,
since the mode in which the spores are developed is but little known;
analogy with the _Trichogastres_ in other points alone leading to the
conclusion that they may produce basidiospores. The slender, elastic
stems which support the peridia in many species are undoubted aids to
the dissemination of the spores.[B]

[Illustration: FIG. 48.--_Diachea elegans._]

Under the name of STYLOSPORES may be classed those spores which in some
orders of _Coniomycetes_ are produced at the apex of short threads,
either enclosed in a perithecium, or seated upon a kind of stroma.
These are exceedingly variable, sometimes large, and multiseptate, at
other times minute, resembling spermatia. In such genera as are
chiefly epiphytal, in _Septoria_, _Phyllosticta_, and their allies,
the minute spores are enclosed within membranaceous perithecia, and
when mature these are ejected from the orifice at the apex, or are
exposed by the breaking off of the upper portion of the perithecia. In
_Diplodia_ and _Hendersonia_ the spores are larger, mostly coloured,
often very fine in the latter genus, and multiseptate, escaping from
the perithecia by a terminal pore. Probably the species are only
pycnidia of _Sphæriacei_, but that is of no consequence in relation
to our present inquiry. Of stylospores which deserve mention on account
of their singularity of form, we may note those of _Dilophospora
graminis_, which are straight, and have two or three hair-like
appendages at each extremity. In _Discosia_ there is a single oblique
bristle at each end, or at the side of the septate spores, whilst in
_Neottiospora_ a tuft of delicate hairs is found at one extremity
only. The appendages in _Dinemasporium_ are similar to those of
_Discosia_. The spores in _Prosthemium_ may be said in some sort to
resemble compound _Hendersonia_, being fusiform and multiseptate, often
united at the base in a stellate manner. In this genus, as in
_Darluca_, _Cytispora_, and the most of those belonging to the
_Melanconiei_, the spores when mature are expelled from the orifice of
the perithecium or spurious perithecium, either in the form of
tendrils, or in a pasty mass. In these instances the spores are more
or less involved in gelatine, and when expelled lie spread over the
matrix, around the orifice; their ultimate diffusion being due to
moisture washing them over other parts of the same tree, since it is
probable that their natural area of dissemination is not large, the
higher plants, of which they are mostly conditions, being developed on
the same branches. More must be known of the relations between
_Melanconium_ and Tulasne's sphæriaceous genus _Melanconis_ before
we can appreciate entirely the advantage to _Melanconium_ and some
other genera, that the wide diffusion of their spores should be
checked by involving them in mucus, or their being agglutinated to the
surface of the matrix, only to be softened and diffused by rain. The
spores in many species amongst the _Melanconiei_ are remarkably fine;
those of _Stegonosporium_ have the endochrome partite and cellular.
In _Stilbospora_ and _Coryneum_ the spores are multiseptate, large,
and mostly coloured. In _Asterosporium_ the spores are stellate,
whilst in _Pestalozzia_ they are septate, with a permanent peduncle,
and crested above with two or three hyaline appendages.

[Illustration: FIG. 49.--Spore of _Hendersonia polycystis_.]

[Illustration: FIG. 50.--Spores of _Dilophospora graminis_.]

[Illustration: FIG. 51.--Spores of _Discosia_.]

[Illustration: FIG. 52.--Spore of _Prosthemium betulinum_.]

[Illustration: FIG. 53.--Spore of _Stegonosporium cellulosum_.]

[Illustration: FIG. 54.--Stylospores of _Coryneum disciforme_.]

[Illustration: FIG. 55.--Spores of _Asterosporium Hoffmanni_.]

[Illustration: FIG. 56.--Spores of _Pestalozzia_.]

[Illustration: FIG. 57.--_Bispora monilioides_.]

The _Torulacei_ externally, and to the naked eye, are very similar to
the black moulds, and the mode of dissemination will be alike in both.
The spores are chiefly compound, at first resembling septate threads,
and at length breaking up into joints, each joint of which possesses
the function of a spore. In some instances the threads are connate,
side by side, as in _Torula hysterioides_, and in _Speira_, being
concentrically arranged in laminæ in the latter genus. The structure
in _Sporochisma_ is very peculiar, the joints breaking up within an
external tube or membrane. The spores in _Sporidesmium_ appear to
consist of irregular masses of cells, agglomerated into a kind of
compound spore. Most of the species become pulverulent, and the spores
are easily diffused through the air like an impalpable dust. They form
a sort of link between the stylospores of one section of the
_Coniomycetes_, and the pseudospores of the parasitical section.

PSEUDOSPORE is, perhaps, the most fitting name which can be applied to
the so-called spores of the parasitical _Coniomycetes_. Their peculiar
germination, and the production of reproductive bodies on the germ
tubes, prove their analogy to some extent with the prothallus of other
cryptogams, and necessitate the use of some term to distinguish them
from such spores as are reproductive without the intervention of a
promycelium. The differences between these pseudospores in the
several genera are confined in some instances to their septation, in
others to their mode of development. In the _Æcidiacei_ the
pseudospores are more or less globose, produced in chains within an
external cellular peridium. In the _Cæomacei_ they are simple,
sometimes produced in chains, and sometimes free, with or without a
caduceous peduncle. In the _Ustilaginei_ they are simple, dark
coloured, and occasionally attached in subglobose masses, as in
_Urocystis_ and _Thecaphora_, which, are more or less compact. In the
_Pucciniæi_ the distinctive features of the genera are based upon the
more or less complex nature of the pseudospores, which are bilocular
in _Puccinia_, trilocular in _Triphragmium_, multilocular in
_Phragmidium_, &c. In the curious genus _Podisoma_ the septate
pseudospores are involved in a gelatinous element. The diffusion of
these fruits is more or less complete according to their compact or
pulverulent nature. In some species of _Puccinia_ the sori are so
compact that they remain attached to the leaves long after they are
dead and fallen. In the genus _Melampsora_, the wedge-shaped
winter-pseudospores are not perfected until after the dead leaves have
for a long time remained and almost rotted on the ground. It is
probable that their ultimate diffusion is only accomplished by the
rotting and disintegration of the matrix. In the _Cæomacei_,
_Ustilaginei_, and _Æcidiacei_ the pseudospores are pulverulent, as in
some species of _Puccinia_, and are easily diffused by the motion of
the leaves in the wind, or the contact of passing bodies. Their
diffusion in the atmosphere seems to be much less than in the case of
the _Hyphomycetes_. By what means such a species as _Puccinia
malvacearum_, which has very compact sori, has become within so short
a period diffused over such a wide area, is a problem which in the
present state of our knowledge must remain unsolved. It may be through
minute and plentiful secondary spores.

[Illustration: FIG. 58.--Pseudospores of _Thecaphora hyalina_.]

[Illustration: FIG. 59.--Pseudospores of _Puccinia_.]

[Illustration: FIG. 60.--Pseudospores of _Triphragmium_.]

[Illustration: FIG. 61.--Pseudospores of _Phragmidium bulbosum_.]

[Illustration: FIG. 62.--_Melampsora salicina._ (Winter fruit.)]

SPERMATIA are very minute delicate bodies found associated with many
of the epiphyllous _Coniomycetes_, and it has been supposed are
produced in conjunction with some of the _Sphæriacei_, but their real
function is at present obscure, and the name is applied rather upon
conjecture than knowledge. It is by no means improbable that spermatia
do exist extensively amongst fungi, but we must wait in patience for
the history of their relationship.

TRICHOSPORES might be applied better, perhaps, than _conidia_ to the
spores which are produced on the threads of the _Hyphomycetes_. Some of
them are known to be the conidia of higher plants; but as this is by no
means the case with all, it would be assuming too much to give the
name of conidia to the whole. By whatever name they may be called, the
spores of the _Hyphomycetes_ are of quite a different type from any yet
mentioned, approximating, perhaps, most closely to the basidiospores
of the _Hymenomycetes_ in some, and _Gasteromycetes_ in others; as,
for instance, in the _Sepedoniei_ and the _Trichodermacei_. The
form of the spores and their size differ materially, as well as the
manner in which they are produced on the threads. In many they are
very minute and profuse, but larger and less plentiful in the
_Dematiei_ than in the _Mucedines_. The spores of some species of
_Helminthosporium_ are large and multiseptate, calling to mind the
spores of the _Melanconiei_. Others are very curious, being stellate in
_Triposporium_, circinate in _Helicoma_ and _Helicocoryne_, angular in
_Gonatosporium_, and ciliate in _Menispora ciliata_. Some are produced
singly and some in chains, and in some the threads are nearly
obsolete. In _Peronospora_, it has been demonstrated that certain
species produce minute zoospores from the so-called spores. The
dissemination of the minute spores of the _Mucedines_ through the
air is undoubted; rain also certainly assists not only in the
dispersion of the spores in this as in other groups, but also in the
production of zoospores which require moisture for that purpose. The
form of the threads, and the mode of attachment of the spores, is far
more variable amongst the _Mucedines_ than the form of the spores, but
the latter are in all instances so slightly attached to their supports
as to be dissevered by the least motion. This aids also in the
diffusion of the spores through the atmosphere.

[Illustration: FIG. 63.--Spores of _Helicocoryne_.]

SPORANGIA are produced in the _Physomycetes_ usually on the tips or
branches of delicate threads, and these when mature dehisce and set
free the minute sporidia. These are so small and uniform in their
character that they require but a passing mention. The method of
diffusion agrees much with that of the _Mucedines_, the walls of the
sporangia being usually so thin and delicate as to be easily ruptured.
Other modes of fructification prevail in some species by the
production of cysts, which are the result of conjugation of the
threads. These bodies are for the most part furnished with thicker and
more resistant walls, and the diffusion of their contents will be
regulated by other circumstances than those which influence the
dispersion of the minute sporidia from the terminal cysts. Probably
they are more perennial in their character, and are assimilated more
to the oogonia of _Cystopus_ and _Peronospora_, being rather of the
nature of resting spores, inasmuch as the same threads usually bear
the terminal fruits.

[Illustration: FIG. 64.--Sporidium of _Genea verrucosa_.]

[Illustration: FIG. 65.--Alveolate sporidium of _Tuber_.]

THECASPORES is a term which may be applied generally to all sporidia
produced in asci, but these are in turn so innumerable and variable
that it will be necessary to treat of some of the groups individually.
The _Thecaspores_, for instance, of the _Tuberacei_ offer several
features whereby they may be distinguished from other thecaspores. The
asci in which these sporidia are generated mostly partake of a broadly
saccate, ovate form. The number of sporidia contained in an individual
ascus is usually less than in the majority of the _Ascomycetes_, and
the sporidia approximate more nearly to the globose form. Usually,
also, they are comparatively large. Many have been figured by Corda[C]
and Tulasne.[D] Three types of spores may be said to prevail in the
_Tuberacei_: the smooth spored, the warted or spinulose, and the
areolate. The first of these may be represented by the _Stephensia
bombycina_, in which the globose sporidia are quite smooth and
colourless. The warted sporidia may be observed in _Genea verrucosa_,
the spinulose in _Tuber nitidum_, and the areolate are present in
_Tuber æstivum_ and _Tuber excavatum_, in which the epispore is
divided into polygonal alveoli, bounded by thin, membranaceous,
prominent partitions. This form of sporidium is very beautiful. In all
no special provision is made for the dissemination of the sporidia,
as, from their subterranean habit, none would be available save the
ultimate dissolution of the external integuments. As they are greedily
devoured by several animals, it is possible that they may be dispersed
through the excrements.

In the _Perisporiacei_ the perithecium has no proper orifice, or
ostiolum, for the discharge of the mature sporidia, which are usually
small, and are disseminated by the irregular rupture of the somewhat
fragile conceptacles. The asci are usually more or less saccate, and
the sporidia approximate to a globose form. The asci are often very
diffluent. In _Perisporium vulgare_ the ovate brown sporidia are at
first, and for some time, attached together in fours in a concatenate
or beaded manner. In some species of _Erysiphei_ the conceptacle
encloses but a single sporangium, in others several, which are
attached together at the base. In some species the sporangia contain
two, in others four, in others eight, and in others numerous sporidia.
In _Chætomium_ the asci are cylindrical, and in most cases the
coloured sporidia are lemon-shaped. When the conceptacles are fully
matured, it is commonly the case that the asci are absorbed and the
sporidia are free in the interior of the conceptacles.

[Illustration: FIG. 66.--Asci, sporidia, and paraphyses of _Ascobolus_
(Boudier).]

Of the fleshy _Discomycetes_ the genus _Peziza_ may be taken as
the type. If the structure which prevails in this genus be brought
to mind, it will be remembered that the hymenium lines an expanded
cup, and that the asci are packed together, side by side, with their
apices outwards, and their bases attached to a substratum of cells
which form the inner layer of the receptacle. The sporidia are
usually eight in each ascus, either arranged in single or double
rows, or irregularly grouped together. The asci are produced in
succession; the later, pressing themselves upwards between those
previously developed, cause the rupture of the mature asci at the
apex and the ejection of the sporidia with considerable force. When
a large _Peziza_ is observed for a time a whitish cloud will be seen
to rise suddenly from the surface of the disc, which is repeated again
and again whenever the specimen is moved. This cloud consists of
sporidia ejected simultaneously from several asci. Sometimes the
ejected sporidia lie like frost on the surface of the disc.
Theories have been devised to account for this sudden extrusion of the
sporidia, in _Ascobolus_, and a few species of _Peziza_, of the asci
also, the most feasible one being the successive growth of the
asci; contraction of the cup may also assist, as well as some other
less potent causes. It may be remarked here that the sporidia in
_Peziza_ and _Helotium_ are mostly colourless, whilst in _Ascobolus_
they pass through pink to violet, or dark brown, and the epispore,
which is of a waxy nature, becomes fissured in a more or less
reticulated manner.

[Illustration: FIG. 67.--Sporidium of _Ostreichnion Americanum_.]

The sporidia in _Hysterium_ proper are usually coloured, often
multiseptate, sometimes fenestrate, and occasionally of considerable
size. There is no evidence that the sporidia are ever excluded in the
same manner as in _Peziza_, the lips closing over the disc so much as
to prevent this. The diffusion of the sporidia probably depends on the
dissolution of the asci, and hence they will not be widely dispersed,
unless, perhaps, by the action of rain.

In _Tympanis_, asci of two kinds have been observed in some species;
one kind containing an indefinite number of very minute bodies
resembling spermatia, and the other octosporous, containing sporidia
of the usual type.

The _Sphæriacei_ include an almost infinite variety in the form and
character of the sporidia. Some of these are indefinite in the number
contained in an ascus, although the majority are eight, and a few
less. In the genera _Torrubia_ and _Hypocrea_ the structure differs
somewhat from other groups, inasmuch as in the former the long
thread-like sporidia break up into short joints, and in the latter the
ascus contains sixteen subglobose or subquadrate sporidia. Other
species contain linear sporidia, which are often the length of the
ascus, and may either be simple or septate. In _Sphæria ulnaspora_ the
sporidia are abruptly bent at the second joint. Shorter fusiform
sporidia are by no means uncommon, varying in the number of septa, and
in constriction at the joints in different species. Elliptic or ovate
sporidia are common, as are those of the peculiar form which may be
termed sausage-shaped. These are either hyaline or coloured of some
shade of brown. Coloured sporidia of this kind are common in _Xylaria_
and _Hypoxylon_, as well as in certain species of the section
_Superficiales_. Coloured sporidia are often large and beautiful: they
are mostly of an elongated, elliptical form, or fusiform. As
noteworthy may be mentioned the sporidia of _Melanconis lanciformis_,
those of _Valsa profusa_, and some species of _Massaria_, the latter
being at first invested with a hyaline coat. Some coloured sporidia
have hyaline appendages at each extremity, as in _Melanconis
Berkeleii_, and an allied species, _Melanconis bicornis_, from the
United States, also some dung _Sphæriæ_, as _S. fimiseda_, included
under the proposed genus _Sordaria_.[E] Hyaline sporidia occasionally
exhibit a delicate bristle-like appendage at each extremity, as in the
_Valsa thelebola_, or with two additional cilia at the central
constriction, as in _Valsa taleola_. A peculiar form of sporidium is
present in certain species of _Sphæria_ found on dung, for which the
generic name of _Sporormia_ has been proposed, in which the sporidium
(as in _Perisporium vulgare_) consists of four coloured ovate joints,
which ultimately separate. Multiseptate fenestrate sporidia are not
uncommon in _Cucurbitaria_ and _Pleospora_, as well as in _Valsa
fenestrata_ and some other species. In the North American _Sphæria
putaminum_ the sporidia are extraordinarily large.

[Illustration: FIG. 68.--Ascus and sporidia of _Hypocrea_.]

[Illustration: FIG. 69.--Sporidium of _Sphæria ulnaspora_.]

[Illustration: FIG. 70.--Sporidia of _Valsa profusa_ (Currey).]

[Illustration: FIG. 71.--Sporidia of _Massaria foedans_. × 400.]

[Illustration: FIG. 72.--Sporidium of _Melanconis bicornis_, Cooke.]

[Illustration: FIG. 73.--Caudate sporidia of _Sphæria fimiseda_.]

[Illustration: FIG. 74.--Sporidia of _Valsa thelebola_.]

[Illustration: FIG. 75.--Sporidia of _Valsa taleola_. × 400.]

[Illustration: FIG. 76.--Sporidium of _Sporormia intermedia_.]

[Illustration: FIG. 77.--Asci and sporidia of _Sphæria_ (_Pleospora_)
_herbarum_.]

[Illustration: FIG. 78.--Sporidium of _Sphæria putaminum_. × 400.]

The dissemination of the sporidia may, from identity of structure in
the perithecium, be deemed to follow a like method in all. When
mature, they are in a great measure expelled from the mouth of the
perithecia, as is evident in species with large dark sporidia, such as
exist in the genera _Hypoxylon_, _Melanconis_, and _Massaria_. In
these genera the sporidia, on maturity, may be observed blackening the
matrix round the mouths of the perithecia. As moisture has an evident
effect in producing an expulsion of sporidia by swelling the
gelatinous nucleus, it may be assumed that this is one of the causes
of expulsion, and therefore of aids to dissemination. When _Sphæriæ_
are submitted to extra moisture, either by placing the twig which
bears them on damp sand, or dipping one end in a vessel of water, the
sporidia will exude and form a gelatinous bead at the orifice. There
may be other methods, and possibly the successive production of new
asci may also be one, and the increase in bulk by growth of the
sporidia another; but of this the evidence is scanty.

Finally, OOGONIA may be mentioned as occurring in such genera as
_Peronospora_ amongst moulds, _Cystopus_ amongst Uredines, and the
_Saprolegniaceæ_ amongst the _Physomycetes_. The zoospores being
furnished with vibratile cilia, are for some time active, and need
only water in which to disseminate themselves, and this is furnished
by rain.

We have briefly indicated the characteristics of some of the more
important types of spores to be found in fungi, and some of the
modes by which it is known, or presumed, that their dissemination
takes place. In this summary we have been compelled to rest content
with suggestions, since an exhaustive essay would have occupied
considerable space. The variability in the fruit of fungi, in so far
as we have failed to demonstrate, will be found exhibited in the
illustrated works devoted more especially to the minute species.[F]

   [A] Cunningham, in "Ninth Annual Report of the Sanitary Commissioner
       with the Government of India." Calcutta, 1872.

   [B] See "Corda Icones," tab. 2.

   [C] Corda, "Icones Fungorum," vol. vi. Prague.

   [D] Tulasne, "Fungi Hypogæi." Paris.

   [E] Winter, "Die Deutschen Sordarien" (1873).

   [F] Corda, "Icones Fungorum," 6 vols. (1837-1842); Sturm,
       "Deutschlands Flora," Pilze (1841); Tulasne, "Selecta Fungorum
       Carpologia;" Bischoff, "Kryptogamenkunde" (1860); Corda,
       "Anleitung zum Studium der Mykologie" (1842); Fresenius,
       "Beiträge zur Mykologie" (1850); Nees Ton Esenbeck, "Das System
       der Pilze" (1816); Bonorden, "Handbuch der Allgemeinen
       Mykologie" (1851).



VII.

GERMINATION AND GROWTH.


In describing the structure of these organisms in a previous
chapter, the modes of germination and growth from the spores have
been purposely excluded and reserved for the present. It may be
assumed that the reader, having followed us to this point, is
prepared for our observations by some knowledge of the chief features
of structure in the principal groups, and of the main distinctions
in the classification, or at least sufficient to obviate any
repetition here. In very many species it is by no means difficult to
induce germination of the spores, whilst in others success is by no
means certain.

M. de Seynes made the _Hymenomycetes_ an especial object of study,[A]
but he can give us no information on the germination and growth of the
spore. Hitherto almost nothing is positively known. As to the form of
the spore, it is always at first spherical, which it retains for a
long time, while attached to the basidia, and in some species, but
rarely, this form is final, as in _Ag. terreus_, &c. The most usual
form is either ovoid or regularly elliptic. All the _Coprini_ have the
spores oval, ovoid, more or less elongated or attenuated from the
hilum, which is more translucent than the rest of the spore. This last
form is rather general amongst the Leucospores, in _Amanita_,
_Lepiota_, &c. At other times the spores are fusiform, with regularly
attenuated extremities, as in _Ag. ermineus_, Fr., or with obtuse
extremities, as in _Ag. rutilans_, Sch. In _Hygrophorus_ they are
rather irregular, reniform, or compressed in the centre all round.
Hoffmann[B] has given a figure taken from _Ag. chlorophanus_, and
Seynes verified it upon _Ag. ceraceus_, Sow. (See figures on page
121.)

The exospore is sometimes roughened, with more or less projecting
warts, as may be seen in _Russula_, which much resembles _Lactarius_
in this as in some other particulars. The spores of the _Dermini_ and
the _Hyporhodii_ often differ much from the sphærical form. In _Ag.
pluteus_, Fr., and _Ag. phaiocephalus_, Bull, there is already a
commencement of the polygonal form, but the angles are much rounded.
It is in _Ag. sericeus_, _Ag. rubellus_, &c., that the polygonal form
becomes most distinct. In _Dermini_ the angles are more or less
pronounced, and become rather acute in _Ag. murinus_, Sow., and _Ag.
ramosus_, Bull. The passage from one to the other may be seen in the
stellate form of the conidia of _Nyctalis_.

It is almost always the external membrane that is coloured, which is
subject to as much variation as the form. The more fine and more delicate
shades are of rose, yellow-dun or yellow, violet, ashy-grey, clear
fawn colour, yellow-orange, olive-green, brick-red, cinnamon-brown,
reddish-brown, up to sepia-black and other combinations. It is only by
the microscope and transparency that one can make sure of these tints;
upon a sufficient quantity of agglomerated spores the colour may be
distinguished by the naked eye. Colour, which has only a slight
importance when considered in connection with other organs, acquires
much in the spores, as a basis of classification.

With the growth of Agarics from the mycelium, or spawn, we are not
deficient in information, but what are the conditions necessary to
cause the spores themselves to germinate before our eyes and produce
this mycelium is but too obscure. In the cultivated species we proceed
on the assumption that the spores have passed a period of probation in
the intestines of the horse, and by this process have acquired a
germinating power, so that when expelled we have only to collect them,
and the excrement in which they are concealed, and we shall secure a
crop.[C] As to other species, we know that hitherto all attempts to
solve the mystery of germination and cultivation has failed. There are
several species which it would be most desirable to cultivate if the
conditions could be discovered which are essential to germination.[D]
In the same manner the _Boleti_ and _Hydnei_--in fact, all other
hymenomycetal fungi, with the exception of the _Tremellini_--still
require to be interrogated by persevering experiment and close inquiry
as to their mode of germination, but more especially as to the
essential conditions under which alone a fruitful mycelium is
produced.

[Illustration: FIG. 79.--(_a_) Basidia and spores of _Exidia spiculosa_;
(_b_) Germinating spore.]

The germination of the spore has been observed in some of the
_Tremellini_. Tulasne described it in _Tremella violacea_.[E] These
spores are white, unilocular, and filled with a plastic matter of
homogeneous appearance. From some portion of their surface an
elongated germ filament is produced, into which the contents of the
reproductive cell pass until quite exhausted. Other spores, perhaps
more abundant, have a very different kind of vegetation. From their
convex side, more rarely from the outer edge, these particular spores
emit a conical process, generally shorter than themselves, and
directed perpendicularly to the axis of their figure. This appendage
becomes filled with protoplasm at the expense of the spore, and its
free and pointed extremity finally dilated into a sac, at first
globose and empty. This afterwards admits into its cavity the plastic
matter contained in its support, and, increasing, takes exactly the
form of a new spore, without, however, quite equalling in size the
primary or mother spore. The spore of the new formation long retains
its pedicel, and the mother spore which produced it, but these latter
organs are then entirely empty and extremely transparent. Sometimes
two secondary spores are thus engendered from the same spore, and
their pedicels may be implanted on the same or on different sides, so
as to be parallel in the former case, and growing in opposite
directions in the latter. The fate of these secondary spores was not
determined.

[Illustration: FIG. 80.--Germinating spore and (_a_) corpuscles of
_Dacrymyces deliquescens_.]

In _Dacrymyces deliquescens_ are found mingled amongst the spores
immense numbers of small round or ovoid unilocular bodies, without
appendages of any kind, which long puzzled mycologists. Tulasne
ascertained that they are derived from the spores of this fungus when
they have become free, and rest on the surface of the hymenium. Each
of the cells of the spore emits exteriorly one or several of these
corpuscles, supported on very short slender pedicels, which remain
after the corpuscles are detached from them. This latter circumstance
evidences that new corpuscles succeed the firstborn one on each
pedicel as long as there remains any plastic matter within the spore.
The latter, in fact, in consequence of this labour of production,
becomes gradually emptied, and yet preserves the generative pedicels
of the corpuscles, even when it no longer contains any solid or
coloured matter. These pedicels are not all in the same plane, as may
be ascertained by turning the spore on its longitudinal axis; but it
often seems to be so when they are looked at in profile, on account of
the very slight distance which then separates them one from another.
It will also be remarked that they are in this case often implanted
all on the same side of the reproductive body, and most often on its
convex side. Their fecundity is exhausted with the plastic contents of
the spore. The corpuscles, when placed in the most favourable
conditions, have never given the least sign of vegetation; they have
also remained for a long time in water without experiencing any
appreciable alteration.

All the individuals of _Dacrymyces deliquescens_ do not produce these
corpuscles in the same abundance; those which bear the most are
recognizable by the pale tint of the reproductive dust with which they
are covered; in others, where this dust preserves its golden
appearance, only a few corpuscles are found. The spores which produce
corpuscles do not appear at all apt to germinate. On the other hand,
multitudes of spores will germinate which had not produced any
corpuscles. Tulasne remarks on this, that these observations would
authorize us to think that all spores, though perfectly identical to
our eyes, have not, without distinction, the same fate, nor doubtless
the same nature; and, in the second place, that these two kinds of
bodies, if they are not always isolated, yet are most frequently met
with on distinct individuals. This author claims for the corpuscles in
question that they are spermatia, and thinks that their origin is only
so far unusual in that they proceed from veritable spores.

The whole of the _Gasteromycetes_ have as yet to be challenged as to
the mode and conditions of germination and development. It is probable
that these will not materially differ from those which prevail in
_Hymenomycetes_.

The germination in _Æcidium_ has been followed out by Tulasne,[F]
either by placing the pseudospores in a drop of water, or confining
them in a moist atmosphere, or by placing the leaves on which the
_Æcidium_ flourishes upon water. The pseudospores plunged in water
germinated more readily than the others. If the conditions were
favourable, germination would take place in a few hours. _Æcidium
Ranunculacearum_, D. C., on leaves of figwort, gives rarely more than
one germinating filament, which soon attains three times the length of
the diameter of the pseudospore. This filament generally remains
simple, sometimes torulose, and distorted in a long spire. Sometimes
it has been seen divided into two branches, nearly equal to each
other. The spore in germinating empties itself of its plastic
contents, contracts, and diminishes in size. The pseudospores of
_Æcidium crassum_, P., emit three long filaments, which describe
spirals, imitating the twistings of the stem of a bean or bindweed. In
_Æcidium Violæ_, Schum, one filament is produced, which frequently
rolls up its anterior extremity into a spire, but more often this same
extremity rises in a large ovoid, irregular vesicle, which continues
the axis of the filament, or makes with it a more or less decided
angle. In whatever manner placed, this vesicle attracts to it all the
orange protoplasm, and hardly does this become settled and complete
before the vesicle becomes the starting point of a new development,
for it begins to produce at its apex a filament, more slender than the
previous one, stiff, and unbranched.

[Illustration: FIG. 81.--Germination of _Æcidium Euphorbia (sylvaticæ)_,
Tulasne.]

According to M. Tulasne, the germination of the pseudospores of
_Æcidium Euphorbiæ_ on _Euphorbia sylvatica_ differ in some respects
from the preceding. When dropped upon water these spores very soon
emit a short tube, which ordinarily curves in an arch or circle,
almost from its origin, attaining a length of from three to six times
the diameter of the spore; then this tube gives rise to four spicules,
each of which produces a small obovate or reniform sporule; the
generation of these sporules absorbs all the plastic matter contained
in the germ-tube, which permits of the observation that it was divided
into four cells corresponding with the number of spicules. These
sporules germinate very rapidly from an indefinite point of their
surface, emitting a filiform process, which is flexuous and very
delicate, not extending more in length than three times that of the
long axis of the sporule, often less, reproducing at its summit a new
sporule, differing in form and size from that which preceded it. This
sporule of the second formation becomes at its apex a vital centre,
and sprouts one or more linear buds, of which the elongation is
occasionally interrupted by the formation of vesicular swellings. As
Tulasne observes, the pseudospores of the _Æcidium_ and the greater
number of Uredines are easily wetted with water before arriving at
maturity; but when they are ripe, on the contrary, they appear to be
clothed with a greasy matter which protects them from the liquid,
forcing them almost all to rest on the surface.

The pseudospores of _Roestelia_ are produced in strings or chaplets,
as in _Æcidium_, with this difference, that instead of being
contiguous they are separated by narrow isthmuses. The ripe
pseudospores are enveloped in a thick tegument, of a dark brown
colour. They germinate readily on water, producing a filament fifteen
times as long as the diameter of the spore. This filament is sometimes
rolled or curved. Towards its extremity it exhibits protuberances
which resemble the rudiments of ramuli, or they terminate in a vesicle
which gives rise to a slender filament. The tegument of these
pseudospores, above all in those which have germinated, and have
consequently become more transparent, it is easy to see has many
pores, or round ostioles.

In _Peridermium_ the pseudospores, when dropped upon water, germinate
at any point of their surface. Sometimes two unequal filaments issue
from the same spore. After forty-eight hours of vegetation in the air,
the greater part had already emitted a multitude of thick little
branches, themselves either simple or branched, giving to the
filaments a peculiar aspect. Tulasne did not on any occasion observe
the formation of secondary spores.

In the Uredines proper the germination seems to be somewhat similar,
or at least not offering sufficient differences to warrant special
reference in _Uredo_, _Trichobasis_, _Lecythea_, &c. In _Coleosporium_
there are two kinds of spores, one kind consisting of pulverulent
single cells, and the other of elongated septate cells, which break up
into obovate joints. Soon after the maturity of the pulverulent
spores, each begins to emit a long tube, which is habitually simple,
and produces at its summit a reproductive cellule, or reniform
sporule. The orange protoplasm passes along the colourless tubes to
the terminal sporule at the end of its vegetation. The two forms of
spores in this genus are constantly found on the same leaf, and in the
same pulvinule, but generally the pulverulent spores abound at the
commencement of the summer. The reniform sporules begin to germinate
in a great number as soon as they are free; some few extend a filament
which remains simple and uniform, but more commonly it forms at its
extremity a second sporule. If this does not become isolated, to play
an independent life, the filament is continued, and new vesicles are
repeated many times.

[Illustration: FIG. 82.--Germinating pseudospores of (_b_) _Coleosporium
Sonchi_; (_s s_) secondary spores, or sporules (Tulasne).]

[Illustration: FIG. 83.--Germinating pseudospore (_b_) of _Melampsora
betulina_ (Tulasne).]

In _Melampsora_ the summer spores are of the _Lecythea_ type, and were
included in that genus till their relation with _Melampsora_ was
clearly made out. The winter spores are in solid pulvinules, and their
fructification takes place towards the end of winter or in the spring.
This phenomenon consists in the production of cylindrical tubes,
which start from the upper extremity of the wedge-shaped spores, or
more rarely from the base. These tubes are straight or twisted, simple
or bifurcated, and each of them very soon emits four monosporous
spicules, at the same time that they become septate. The sporules are
in this instance globose.

[Illustration: FIG. 84.--Germinating pseudospore of _Uromyce
appendiculatus_. (Tulasne.)]

In _Uromyces_ germination follows precisely the same type as that of
the upper cell of _Puccinia_; in fact, Tulasne states that it is very
difficult to say in what they differ from the _Pucciniæ_ which are
accidentally unilocular.

In _Cystopus_ a more complex method prevails, which will be examined
more closely hereafter.

In _Puccinia_, as already observed when describing their structure,
the pseudospores are two-celled. From the pores of each cell, which
are near the central septum, springs a clavate tube, which attains two
or three times the total length of the fruit, and of which the very
obtuse extremity curves more or less in the manner of a crozier.[G]
This tube, making a perfectly uncoloured transparent membrane, is
filled with a granular and very pale plastic matter at the expense
of the generative cell, which is soon rendered vacant; then it
gives rise to four spicules, usually on the same side, and at the
summit of these produces a reniform cellule. The four sporules so
engendered exhaust all the protoplasm at first contained in the
generative cell, so that their united capacity proves to be evidently
much insufficient to contain it, the more so as it leads to the
belief that this matter undergoes as it condenses an elaboration
which diminishes its size. In all cases the spicule originates
before the sporule which it carries, and also attains its full length
when the sporule appears. The form of the latter is at first
globular, then ellipsoid, and more or less curved. All these phases
of vegetation are accomplished in less than twelve hours, and if
the spore is mature and ready for germination, it is sufficient to
provoke it by keeping the pseudospores in a humid atmosphere.
During this process the two cells do not separate, nor does one
commence germination before the other, but both simultaneously.
When the sporules are produced, the protospore, somewhat analogous
to a prothallus, has performed its functions and decays. Towards
the time of the falling of the sporules they are nearly all divided
into four unequal cells by transverse and parallel septa. These
sporules in time produce, from any point on their surface, a
filament, which reproduces a new sporule, resembling the first, but
generally smaller. This sporule of the second generation ordinarily
detaches itself from its support before germinating.

[Illustration: FIG. 85.--Germinating pseudospore of _Puccinia Moliniæ_.
(Tulasne.)]

[Illustration: FIG. 86.--Germinating pseudospore of _Triphragmium
ulmariæ_ (Tulasne.)]

The pseudospores of _Triphragmium ulmariæ_ have been seen in April
germinating on old leaves of the meadowsweet which survived the
winter, whilst at the same time new tufts of the spores were being
developed on the leaves of the year. These fruits of the spring
vegetation would not germinate the same year. Each cell in germination
emits a long cylindrical filament, containing a brownish protoplasm,
on which four spicules, bearing as many sporules, are generated.

[Illustration: FIG. 87.--Germinating pseudospore of _Phragmidium
bulbosum_. (Tulasne.)]

The germination of the black fruits of _Phragmidium_ only appears to
take place in the spring. It greatly resembles that in _Puccinia_,
except that the filament is shorter, and the sporules are spherical
and orange-coloured, instead of being kidney-shaped and pale. In the
species found on the leaves of the common bramble, the filament
emitted by each cell attains three or four times the length of the
fruit. The granular orange protoplasm which fills it passes ere long
into the sporules, which are engendered at the extremity of pointed
spicules. After the long warty fruits are emptied of their contents
they still seem as dark as before, but the pores which are pierced in
the sides, through which the germinating filaments have proceeded, are
more distinctly visible.

It will be observed that throughout all these allied genera of
_Uromyces_, _Puccinia_, _Triphragmium_, and _Phragmidium_ the same
type of germination prevails, which confirms the accuracy of their
classification together, and renders still less probable the supposed
affinity of _Phragmidium_ with _Sporidesmium_, which was at one time
held by very astute mycologists, but which is now abandoned. This
study of germination leads also to a very definite conclusion with
regard to the genus _Uromyces_--that it is much more closely related
to _Puccinia_ and its immediate allies than to other unicellular
Uredines.

The germination of the pseudospores of the gelatinous Uredines of the
genus _Podisoma_ was studied by Tulasne.[H] These pretended spores,
he writes, are formed of two large conical cells, opposed by their
base and easily separating. They vary in length. The membrane of which
they are formed is thin and completely colourless in most of them,
though much thicker and coloured brown in others. It is principally
the spores with thin membranes that emit from near the middle very
obtuse tubes, into which by degrees, as they elongate, the contents of
the parent utricles pass. Each of the two cells of the supposed spore
may originate near its base four of these tubes, opposed to each other
at their point of origin, and their subsequent direction; but it is
rather rare for eight tubes, two by two, to decussate from the same
spore or basidium. Usually there are only two or three which are
completely developed, and these tend together towards the surface of
the fungus, which they pass, and expand at liberty in the air. The
tubes generally become thicker by degrees as they elongate, some only
slightly exceeding the length of the protospores. Others attain three
or four times that length, according to the greater or less distance
between the protospore and the surface of the plant. In the longest
tubes it is easy to observe how the colouring matter passes to their
outer extremity, leaving the portion nearest to the parent cell
colourless and lifeless. When nearly attaining their ultimate
dimensions, all the tubes are divided towards their outer extremity by
transverse septa into unequal cells; then simple and solitary
processes, of variable length and form, but attenuated upwards,
proceed from each segment of the initial tube, and produce at their
extremity an oval spore (teleutospore, Tul.), which is slightly curved
and unilocular. These spores absorb all the orange endochrome from the
original tubes. They appear in immense numbers on the surface of the
fungus, and when detached from their spicules fall upon the ground or
on any object which may be beneath them. So freely are they deposited
that they may be collected on paper, or a slip of glass, like a fine
gold-coloured powder. Again, these secondary spores (teleutospores)
are capable of germination, and many of them will be found to have
germinated on the surface of the _Podisoma_ whence they originated.
The germ filament which they produce springs habitually from the side,
at a short distance from the hilum, which indicates the point of
attachment to the original spicule. These filaments will attain to
from fifteen to twenty times the diameter of the spore in length
before branching, and are in themselves exceedingly delicate. The
tubes which issue from the primary spores (protospores, Tul.) are not
always simple, but sometimes forked; and the cells which are
ultimately formed at their extremities, though producing filiform
processes, do not always generate secondary spores (teleutospores) at
their apices. This mode of germination, it will be seen, resembles
greatly that which takes place in _Puccinia_.

[Illustration: FIG. 88.--Germinating pseudospores of _Podisoma Juniperi_.
(Tulasne)]

The germination of the Ustilagines was in part examined by Tulasne,
but since has received accessions through the labours of Dr. A.
Fischer von Waldheim.[I] Nothing, however, of any importance is added
to our knowledge of the germination of _Tilletia_, which was made
known as early as 1847.[J] After some days a little obtuse tube is
protruded through the epispore, bearing at its apex long fusiform
bodies, which are the sporules of the first generation. These
conjugate by means of short transverse tubes, after the manner of the
threads of _Zygnema_. Afterwards long elliptical sporules of the
second generation are produced on short pedicels by the conjugated
fusiform bodies of the first generation. (Fig. 89, _ss._) Ultimately
these sporules of the second generation germinate, and generate, on
short spicules, similar sporules of a third generation. (Fig. 89,
_st._)

[Illustration: FIG. 89.--Germinating pseudospore (_g_) of _Tilletia
caries_ with secondary spores in conjugation. (Tul.)]

In _Ustilago (flosculorum)_ germination takes place readily in warm
weather. The germ tube is rather smaller at its base than further on.
In from fifteen to eighteen hours the contents become coarsely
granular; at the same time little projections appear on the tube which
are narrowed at the base, into which some of the protoplasm passes.
These ultimately mature into sporules. At the same time a terminal
sporule generally appears on the threads. Secondary sporules
frequently grow from the primary, which are rather smaller, and these
occasionally give rise to a third generation.

In _Urocystis (pompholygodes)_ the germinating tubes spring
exclusively from the darker central cells of the clusters. From these
are developed at their extremity three or four linear bodies, as in
_Tilletia_, but after this no further development has as yet been
traced. It may be remarked here that Waldheim observed similar
conjugation of the sporules in some species of _Ustilago_ as have
been remarked in the sporules of the first generation in _Tilletia_.

[Illustration: FIG. 90.--Pseudospore of _Ustilago receptaculorum_ in
germination, and secondary spores in conjugation. (Tul.)]

[Illustration: FIG. 91.--Conidia and zoospores of _Cystopus candidus_;
_a._ conidium with the plasma divided; _b._ zoospores escaping; _c._
zoospores escaped from the conidium; _d._ active zoospores; _e._
zoospores, having lost their cilia, commencing to germinate.]

Returning to _Cystopus_, as the last of the Uredines, we must briefly
recapitulate the observations made by Professor de Bary,[K] who, by
the bye, claims for them an affinity with _Peronospora_ (Mucedines but
too well known in connection with the potato disease), and _not_ with
the Uredines and their allies. In this genus there are two kinds of
reproductive organs, those produced on the surface of the plant
bursting through the cuticle in white pustules, and which De Bary
terms _conidia_, which are generated in chains, and certain globose
bodies termed _oogonia_, which are developed on the mycelium in the
internal tissues of the foster plant. When the conidia are sown on
water they rapidly absorb the moisture, and swell; the centre of one
of the extremities soon becomes a large obtuse papilla resembling the
neck of a bottle. This is filled with a granular protoplasm, in which
vacuoles are formed. Soon, however, these vacuoles disappear, and very
fine lines of demarcation separate the protoplasm into from five to
eight polyhedric portions, each presenting a little faintly-coloured
vacuole in the centre (_a_). Soon after this division the papilla at
the extremity swells, opens itself, and at the same time the five to
eight bodies which had formed in the interior are expelled one by one
(_b_). These are zoospores, which at first take a lenticular form,
and group themselves before the mouth of the parent cell in a globose
mass (_c._) Very soon, however, they begin to move, and then vibratile
cilia show themselves (_d_), and by means of these appendages the
entire globule moves in an oscillating manner as one by one the
zoospores disengage themselves, each becoming isolated and swimming
freely in the surrounding fluid. The movement is precisely that of the
zoospores of Algæ.

[Illustration: FIG. 92.--Resting spore of _Cystopus candidus_ with
zoospores escaped.]

The generation of the zoospores commences within from an hour and a
half to three hours after the sowing of the conidia on water. From the
oogonia, or resting spores, similar zoospores, but in greater number,
are generated in the same manner, and their conduct after becoming
free is identical. Their movements in the water usually last from two
to three hours, then they abate, the cilia disappear, and the spore
becomes immovable, takes a globose form, and covers itself with a
membrane of cellulose. Afterwards the spore emits, from any point
whatever of its surface, a thin, straight or flexuous tube, which
attains a length of from two to ten times the diameter of the spore.
The extremity becomes clavate or swollen, after the manner of a
vesicle, which receives by degrees the whole of the protoplasm.

De Bary then proceeds to describe experiments which he had performed
by watering growing plants with these zoospores, the result being that
the germinating tubes did not penetrate the epidermis, but entered by
the stomates, and there put forth an abundant mycelium which traversed
the intercellular passages. Altogether the germination of these
conidia or zoospores offers so many differences from the ordinary
germination of the Uredines, and is so like that which prevails in
_Peronospora_, in addition to the fact of both genera producing winter
spores or oogonia, that we cannot feel surprised that the learned
mycologist who made these observations should claim for _Cystopus_ an
affinity with _Peronospora_ rather than with the plants so long
associated with it amongst the _Coniomycetes_.

In passing from these to the _Mucedines_, therefore, we cannot do so
more naturally than by means of that genus of white moulds to which we
have just alluded. The erect branched threads bear at the tip of their
branchlets spores, or conidia, which conduct themselves in a like
manner to the organs so named in _Cystopus_, and oogonia or resting
spores developed on the mycelium within the tissues of the foster
plant also give origin to similar zoospores.

The conidia are borne upon erect, elongated filaments, originating
from the creeping mycelium. These threads are hollow, and rarely
septate; the upper portion divided into numerous branches, and these
again are subdivided, the ultimate ramuli each terminated by a single
conidium. This body when mature is oval or elliptical, filled with
protoplasm, but there is a diversity in their mode of germination. In
the greater part, of which _P. effusa_ may be taken as an example, the
conidia have the function of simple spores. Placed in favourable
conditions, each of them puts forth a germ-tube, the formation of
which does not differ in any essential point from what is known of the
spores of the greater part of fungi.

The short oval conidia of _P. gangliformis_ have little obtuse papillæ
at their apex, and it is at this point that germination commences.

The conidia of _P. densa_ are similar, but the germination is
different. When placed in a drop of water, under favourable
circumstances, the following changes may be observed in from four to
six hours. The protoplasm, at first uniformly distributed in all the
conidia, appears strewn with semi-lenticular, and nearly equidistant
vacuoles, of which the plane face is immediately in contact with the
periphery of the protoplasm. These vacuoles number from sixteen to
eighteen in _P. macrocarpa_, but are less numerous in _P. densa_. A
short time after the appearance of the vacuoles the entire conidium
extends itself so that the papilla disappears. Suddenly it reappears,
elongates itself, its attenuated membrane vanishes, and the protoplasm
is expelled by the narrow opening that remains in place of the
papilla. In normal cases the protoplasm remains united in a single
mass that shows a clear but very delicate outline. When it has reached
the front of the opening in the conidium, which is thus emptied, the
mass remains immovable. In _P. densa_ it is at first of a very
irregular form, but assumes by degrees a regular globose shape. This
is deprived of a distinct membrane, the vacuoles that disappeared in
the expulsion again become visible, but soon disappear for a second
time. The globule becomes surrounded with a membrane of cellulose, and
soon puts out from the point opposite to the opening of the conidium a
thick tube which grows in the same manner as the germ-tube of the
conidia in other species. Sometimes the expulsion of the protoplasm is
not completely accomplished; a portion of it remaining in the membrane
of the conidium detaches itself from the expelled portion, and while
this is undergoing changes takes the form of a vesicle, which is
destroyed with the membrane. It is very rare that the protoplasm is
not evacuated, and that the conidia give out terminal or lateral tubes
in the manner that is normal to other species without papillæ. The
germination just described does not take place unless the conidia are
entirely surrounded by water; it is not sufficient that they repose
upon its surface. Besides, there is another condition which, without
being indispensable, has a sensible influence on the germination of
_P. macrocarpa_, and that is the exclusion of light. To ascertain if
the light or the darkness had any influence, two equal sowings were
placed side by side, the one under a clear glass bell, the other under
a blackened glass bell. Repeated many times, these experiments always
gave the same result--germination in from four to six hours in the
conidia under the blackened glass; no change in those under the clear
glass up to the evening. In the morning germination was completed.

The conidia of _P. umbelliferarum_ and _P. infestans_[L] show an
analogous structure. These bodies, if their development be normal,
become zoosporangia. When they are sown upon water, one sees at the
end of some hours the protoplasm divided by very fine lines, and each
of the parts furnished with a small central vacuole. Then the papilla
of the conidium disappears. In its place appears a rounded opening, by
which the parts of the protoplasm are expelled rapidly, one after the
other. Each of these, when free, immediately takes the form of a
perfect zoospore, and commences to agitate itself. In a few moments
the sporangium is empty and the spores disappear from the field of the
microscope.

The zoospores are oval or semi-oval, and in _P. infestans_ the two
cilia spring from the same point on the inferior border of the
vacuole. Their number in a sporangium are from six to sixteen in _P.
infestans_, and from six to fourteen in _P. umbelliferarum_. The
movement of the zoospores ceases at the end of from fifteen to thirty
minutes. They become motionless, cover themselves with a membrane of
cellulose, and push out slender bent germ-tubes which are rarely
branched. It is but seldom that two tubes proceed from the same spore.
The same development of the zoospores in _P. infestans_ is favoured by
the exclusion of the light. Placed in a position moderately lighted or
protected by a blackened bell, the conidia very readily produced
zoospores.

A second form of germination of the conidia in _P. infestans_, when
sown upon a humid body or on the surface of a drop of water, consists
in the conidium emitting from its summit a simple tube, the extremity
of which swells itself into the form of an oval vesicle, drawing to
itself, little by little, all the protoplasm contained in the
conidium. Then it isolates itself from the germ-tube by a septum, and
takes all the essential characteristics of the parent conidium. This
secondary conidium can sometimes engender a third cellule by a similar
process. These secondary and tertiary productions have equally the
character of sporangia. When they are plunged into water, the ordinary
production of zoospores takes place.

Lastly, there is a third mode of germination which the conidia of _P.
infestans_ manifest, and which consists in the conidium emitting from
its summit a simple or branched germ-tube. This grows in a similar
manner to the conidia first named as of such species as _P. effusa_.
The conditions which control this form of germination cannot be
indicated, since some conidia which germinate after this manner will
sometimes be found mixed with others, the majority of which furnish
zoospores. It may be that the conidia themselves are in some sort of
abnormal condition.

In all the species examined the conidia possess the power of
germination from the moment of their maturity. The younger they are
the more freely they germinate. They can retain this power for some
days or weeks, provided they are not entirely dried. Dessication in an
ordinary temperature seemed sufficient to destroy the faculty of
germinating in twenty-four hours, when the conidia had been removed
from the leaves on which they were produced. They none of them
retained the faculty during a few months, hence they cannot preserve
it during the winter.

The germs of _Peronospora_ enter the foster plant if the spores are
sown upon a part suitable for the development of the parasite. It is
easy to convince one's self that the mycelium, springing from the
penetrating germs, soon takes all the characters that are found in the
adult state. Besides, when cultivated for some time, conidiiphorous
branches can be seen growing, identical with those to which it owes
its origin. Such cultivation is so readily accomplished that it can be
made upon cut leaves preserved fresh in a moist atmosphere.

In the species of _Peronospora_ that inhabit perennial plants, or
annual plants that last through the winter, the mycelium hidden in the
tissues of the foster-plant lasts with it. In the spring it
recommences vegetation, and emits its branches into the newly-formed
organs of its host, there to fructify. The _Peronospora_ of the potato
is thus perennial by means of its mycelium contained in the browned
tissue of the diseased tubers. When in the spring a diseased potato
begins to grow, the mycelium rises in the stalk, and soon betrays
itself by blackish spots. The parasites can fructify abundantly on
these little stalks, and in consequence propagate themselves in the
new season by the conidia coming from the vivacious mycelium.

The diseased tubers of the potato always contain the mycelium of _P.
infestans_, which never fructifies there as long as the skin of the
tuber is intact. But when, in cutting the tuber, the parenchyma
occupied by the mycelium is exposed to the contact of the air, it
covers itself with conidia-bearing branches at the end of from
twenty-four to forty-eight hours. Analogous results are obtained with
the stalks of the potato. It is evident that in these experiments
nothing is changed except the contact of the air; the specific
conditions particularly remain the same. It appears, therefore, that
it is this contact alone which determines generally the production of
the conidiiferous branches.[M]

The mode of germination and development in the Mucors has been studied
by several observers, but most recently by Van Tieghem and Le
Monnier.[N] In one of the common forms, the _Mucor phycomyces_ of some
authors, and the _Phycomyces nitens_ of others, the process is given
in detail. In this species germination will not take place in ordinary
water, but it readily takes place in orange juice and other media. The
spore loses colour, swells, and absorbs fluid around it until double
its original size and ovoid. Then a thick thread is emitted from one
or both extremities, which elongates and becomes branched in a pinnate
manner. Sometimes the exospore is ruptured and detached loosely from
the germinating spore. After about forty-eight hours from the first
sowing, the mycelium will send branches into the air, which again
become abundantly branched; other short submerged branches will also
remain simple, or have tuft-like ramifications, each terminating in a
point, so as to bristle with spiny hairs. In two or three days
abruptly swollen branches, of a club shape, will make their appearance
on the threads both in the air and in the fluid. Sometimes these
branches are prolonged into an equal number of sporangia-bearing
threads, but most frequently they divide first at their swollen
summits into numerous branches, of which usually one, sometimes two
or three, develop into sporangia-bearing threads, while the rest are
short, pointed, and form a tuft of rootlets. Sometimes these rootlets
reduce themselves to one or more rounded protuberances towards the
base of the sporangia-bearing threads.

[Illustration: FIG. 93.--Zygospores of _Mucor phycomyces_. (Van Tieghem.)]

There are often also a certain number of the branches which had
acquired a clavate shape, and do not erect themselves above the
surface, instead of producing a fertile thread, which would seem to
have been their first intention, become abruptly attenuated, and are
merely prolonged into a mycelial filament. Although in other species
chlamydospores are formed in such places on the mycelium, nothing of
the kind has been traced in this species, more than here indicated.
Occasionally, when germination is arrested prematurely, certain
portions of the hyphæ, in which the protoplasm maintains its vitality,
become partitioned off. This may be interpreted as a tendency towards
the formation of chlamydospores, but there is no condensation of
protoplasm, or investiture with a special membrane. Later on this
isolated protoplasm is gradually altered, separating into somewhat
regular ovoid or fusiform granules, which have, to a certain extent,
the appearance of spores in an ascus, but they seem to be incapable of
germination.

Another method of reproduction, not uncommon in _Mucorini_, is
described by Van Tieghem in this species. Conjugating threads on the
substratum by degrees elaborate zygospores, but these, contrary to
the mode in other species, are surrounded by curious branched
processes which emanate from the arcuate cells on either side of the
newly-developed zygospore. This system of reproduction is again
noticed more in detail in the chapter on polymorphism.

M. de Seynes has given the details of his examination of the sporidia
of _Morchella esculenta_ during germination.[O] A number of these
sporidia, placed in water in the morning, presented, at nine o'clock
of the same evening, a sprout from one of the extremities, measuring
half the length of the spore. In the morning of the next day this
sprout had augmented, and become a filament three or four times as
long. The next day these elongated filaments exhibited some transverse
divisions and some ramifications. On the third day, the germination
being more advanced, many more of the sporidia were as completely
changed, and presented, in consequence of the elongation, the
appearance of a cylindrical ruffle, the cellular prolongations arising
from the germination having a tendency towards one of the extremities
of the longer axis of the sporidium, and more often to the two opposed
extremities, either simultaneously or successively. Out of many
hundreds of sporidia examined during germination, he had only seen a
very few exceptions to this rule, among which he had encountered the
centrifugal tendency to vegetate by two opposed filaments, proving
that if it bears a second by the side of the primal filament situated
at one of the poles, a second would also be seen from the side of the
filament coming from the opposite pole.

Before being submitted to the action of water, the contents of the
sporidia seemed formed of two distinct parts, one big drop of yellow
oil of the same form as the sporidium, with the space between it and
the cell wall occupied by a clear liquid, more fluid and less
refractive, nearly colourless, or at times slightly roseate. As the
membrane absorbed the water by which it was surrounded, the quantity
of this clear liquid was augmented, and the rosy tint could be more
easily distinguished. All the contents of the spore, which up to this
time remained divided into two parts, presented altogether one aspect,
only containing numerous granulations, nearly of equal size,
completely filling it, and reaching the inner face of the sporic
membrane.

After this time the sporidium augments in size very rapidly, becoming
at times irregular, and sometimes even as much as from two to three
times its original dimensions, then there appears at the surface,
usually at one of the poles of the ellipse, a small prominence, with
an extremely fine membrane, which does not appear to separate itself
from that which surrounds the sporidium, and it is difficult to say
whether it is a prolongation of the internal membrane going across the
outside, or simply a prolongation caused by a continuation of tissue
of an unique membrane. Sometimes there may be seen at the point where
the primal filament issues from the sporidium a circular mark, which
appears to indicate the rupture of the external membrane. From this
time another change comes over the contents. We again find the yellow
oily liquid, now occupying the external position, with some drops of
colourless or roseate liquid in the centre, so that the oily liquid
and the more limpid fluid interchange the positions which they
occupied previous to the commencement of germination. Whether these
two fluids have undergone any change in their constitution is
difficult to determine, at all events the oily liquid appears to be
less refractive and more granular, and it may be that it is a product
of new formation, containing some of the elements of the primitive
oily drop. Having regard to the delicate character of the membrane of
the germinating filaments, De Seynes supposed that it might offer
greater facility for the entrance of water by endosmose, and account
for the rapid enlargement of the sporidia. By a series of experiments
he became satisfied that this was the case to a considerable extent,
but he adds:--"I cannot help supposing that a greater absorption of
greasy matter in the cell which is the first product of germination
raises an objection to an aqueous endosmose. One can also see in this
experience a proof of the existence of two special membranes, and so
suppose that the germinative cell is the continuation of the internal
membrane, the external membrane alone being susceptible of absorbing
the liquids, at least with a certain rapidity."

[Illustration: FIG. 94.--Sporidium of _Ascobolus_ germinating.]

In other _Discomycetes_ germination takes place in a similar manner.
Boudier[P] narrates that in _Ascobolus_, when once the spore reaches a
favourable place, if the circumstances are good, _i.e._, if the
temperature is sufficiently high and the moisture sufficient, it will
germinate. The time necessary for this purpose is variable, some hours
sufficing for some species; those of _A. viridis_, for example,
germinate in eight or ten hours, doubtless because, being terrestrial,
it has in consequence less heat. The spore slightly augments in size,
then opens, generally at one or other extremity, sometimes at two, or
at any point on its surface, in order to pass the mycelium tubes. At
first simple, without septa, and granular in the interior, above all
at the extremity, these tubes, the rudiment of the mycelium, are not
long in elongating, in branching, and later in having partitions.
These filaments are always colourless, only the spore may be coloured,
or not. Coemans has described them as giving rise to two kinds of
conidia,[Q] the one having the form of _Torula_, when they give rise
to continuous filaments, the other in the form of _Penicillium_, when
they give birth to partitioned filaments. De Seynes could never obtain
this result. Many times he had seen the _Penicillium glaucum_ invade
his sowings, but he feels confident that it had nothing to do with the
_Ascobolus_. M. Woronin[R] has detailed some observations on the
sexual phenomena which he has observed in _Ascobolus_ and _Peziza_,
and so far as the scolecite is concerned these have been confirmed by
M. Boudier.

There is no reason for doubt that in other of the _Discomycetes_ the
germination of the sporidia is very similar to that already seen and
described, whilst in the _Pyrenomycetes_, as far as we are aware,
although the production of germinating tubes is by no means difficult,
development has not been traced beyond this stage.[S]

   [A] Seynes, J. de, "Essai d'une Flore Mycologique de la Montpellier,"
       &c. (1863), p. 30.

   [B] Hoffman, "Icones Analyticæ Fungorum."

   [C] The spores of Agarics which are devoured by flies, however,
       though returned in their dung in an apparently perfect state,
       are quite effete. It is, we believe, principally by the
       _Syrphidæ_, which devour pollen, that fungus spores are
       consumed.

   [D] All attempts at Chiswick failed with some of the more esculent
       species, and Mr. Ingram at Belvoir, and the late Mr. Henderson
       at Milton, were unsuccessful with native and imported spawn.

   [E] Tulasne, "On the Organization of the Tremellini," "Ann. des. Sci.
       Nat." 3^me sér. xix. (1853), p. 193.

   [F] Tulasne, "Mémoire sur les Urédinées."

   [G] Tulasne, in his "Memoirs on the Uredines."

   [H] Mr. Berkeley has lately published a species under the name of _P.
       Ellisii_, in which the gelatinous element is scarcely
       discernible till the plant is moistened. There are two septa in
       this species, and another species or form has lately been
       received from Mr. Ellis which has much shorter pedicels, and
       resembles more closely _Puccinia_, from which it is chiefly
       distinguished by its revivescent character.

   [I] Von Waldheim, on the "Development of the Ustilagineæ," in
       "Pringsheim's Jahrbucher," vol. vii. (1869); translated in
       "Transactions of N. Y. State Agricultural Society for 1870."

   [J] Berkeley, on the "Propagation of Bunt," in "Trans. Hort. Soc.
       London," ii. (1847), p. 113; Tulasne, second memoir, in "Ann.
       des. Sci. Nat." ii. (4^me sér.), p. 77; Cooke, in "Journ.
       Quekett Micro. Club," i. p. 170.

   [K] De Bary, "Recherches," &c. in "Annales des Sciences Naturelles"
       (4^me sér.), xx. p. 5; Cooke in "Pop. Sci. Rev." iii. (1864),
       p. 459.

   [L] This is the mould which produces the potato murrain.

   [M] De Bary, "Champignons parasitiques," in "Annales des Sci. Nat."
       (4^me sér.), xx. p. 5; Cooke, "Microscopic Fungi," cap. xi. p.
       138; "Popular Science Review," iii. 193 (1864).

   [N] Van Tieghem and Le Monnier, "Researches on Mucorini," in "Ann.
       des Sci. Nat." (1873), xvii. p. 261; Summary in "Quart. Journ.
       Micro. Science" (2nd ser.), xiv. p. 49.

   [O] Seynes, "Essai d'une Flore Mycologique."

   [P] Boudier, "Mémoire sur l'Ascoboles," pt. i. iv. f. 13-15.

   [Q] Coemans, "Spicilége Mycologique," i. p. 6.

   [R] Woronin, "Abhandlungen der Senchenbergischen Naturfor.
       Gesellschaft" (1865), p. 333.

   [S] In the very important observations made by Dr. Cunningham at
       Calcutta, on substances floating in the atmosphere, it appeared
       that the sporidia of many _Sphæriæ_ actually germinated after
       being taken up by the air. The multitude of fungus spores which
       were observed in every case was quite extraordinary.



VIII.

SEXUAL REPRODUCTION.


The existence of some sort of sexual reproduction in Fungi has long been
suspected, although in earlier instances upon insufficient grounds; but
of late years observations have multiplied and facts accumulated which
leave no doubt of its existence. If the _Saprolegniæ_ are left out of the
question as disputed Fungi, there still remain a number of well
authenticated instances of the phenomena of copulation, and many other
facts which indicate some sort of sexual relationship. The precise
manner in which those minute bodies, so common amongst the _Sphæronemei_,
which we prefer to call stylospores, perform their functions is still to a
great extent a mystery; yet it is no longer doubted that certain species
of _Aposphæria_, _Phoma_, _Septoria_, &c., are only conditions of some
species of _Sphæria_, often developed and matured in close proximity to
them on the same host. In _Æcidium_, _Roestelia_, &c., spermogonia are
produced plentifully on or near the same spots on which the
fructification appears, either simultaneously or at a later period.[A] The
relation of _Cytispora_ to _Valsa_ was suspected by Fries very many
years ago, and, as since demonstrated, with very good reason. All
attempts, however, to establish anything like sexual reproduction in
the higher forms of _Hymenomycetes_ have at present been unsuccessful; and
the same may be said of the _Gasteromycetes_; but in _Ascomycetes_ and
_Physomycetes_ instances abound.

We know not whether any importance is to be attached to the views of
M. A. S. Oersted,[B] which have not since been confirmed, but which
have been cited with some approval by Professor de Bary, as to a trace
of sexual organs in _Hymenomycetes_. He is supposed to have seen in
_Agaricus variabilis_, P., oocysts or elongated reniform cells, which
spring up like rudimentary branches of the filaments of the mycelium,
and enclose an abundant protoplasm, if not even a nucleus. At the base
of these oocysts appear the presumed antheridia, that is to say, one
or two slender filaments, which generally turn their extremities
towards the oocysts, and which more rarely are applied to them. Then,
without ulteriorily undergoing any appreciable modifications, the
fertile cell or oocyst becomes enveloped in a network of filaments of
mycelium which proceed from the one which bears it, and this tissue
forms the rudiments of the cap. The reality of some kind of
fecundation in this circumstance, and the mode of the phenomena, if
there is one, are for the present equally uncertain. If M. Oersted's
opinion is confirmed, naturally the whole of the cap will be the
product of fecundation. Probably Karsten (Bonplandia, 1862, p. 62) saw
something similar in _Agaricus campestris_, but his account is
obscure.

[Illustration: FIG. 95.--Zygospore of _Mucor phycomyces_.]

In _Phycomyces_ the organs of reproduction have been subjected to
close examination by Van Tieghem,[C] and although he failed to
discover chlamydospores in this, he describes them in other Mucors. In
this species, besides the regular sexual development, by means of
sporangia, there is a so-called sexual reproduction by means of
zygospores, which takes place in this wise. The threads which
conjugate to form the zygospores are slender and erect on the surface
of the substratum. Two of these threads come into close contact
through a considerable length, and clasp each other by alternate
protuberances and depressions. Some of the protuberances are prolonged
into slender tubes. At the same time the free extremities of the
threads dilate, and arch over one towards the other until their tops
touch like a vice, each limb of which rapidly increases in size. Each
of these arcuate, clavate cells has now a portion of its extremity
isolated by a partition, by means of which a new hemispherical cell is
formed at the end of each thread at its point of junction with the
opposed thread. These cells become afterwards cylindrical by pressure,
the protoplasm is aggregated into a mass, the double membrane at the
point of first contact is absorbed, and the two confluent masses of
protoplasm form a zygospore invested with a tubercular coat and
enveloped by the primary wall of the two conjugating cells. During
this formation of the zygospore, the two arched cells whence the
zygospore originated develop a series of dichotomous processes in
close proximity to the walls which separate them from the zygospore.
These processes appear at first on one of the arcuate cells in
successive order. The first makes its appearance above upon the convex
side; the succeeding ones to the right and left in descending order;
the last is in the concavity beneath. It is only after the development
of this that the first process appears on the opposite cell, which is
followed by others in the same order. These dichotomous processes are
nothing more than branches developed from the arcuate, or mother
cells. During all these changes, while the zygospore enlarges, the
wall of the arcuate cells becomes coloured brown. This colouring is
more marked on the convex side, and it shows itself first in the cell
on which the dichotomous branches are first produced, and which
retains the darker tint longer than the other. The zone from whence
the processes issue, and also the processes themselves, have their
walls blackened deeply, while the walls of the conjugated cells, which
continue to clothe the zygospore during the whole of its development,
are bluish-black. By pressure, the thin brittle coat which envelopes
the zygospore is ruptured, and the coat of the zygospore exposed,
formed of a thick cartilaginous membrane, studded with large irregular
warts.

The germination of the zygospores in this species has not as yet been
observed, but it is probably the same or very similar to that observed
in other species of _Mucor_. In these the rough tuberculate epispore
splits on one side, and its internal coat elongates itself and
protrudes as a tube filled with protoplasm and oil globules,
terminating in an ordinary sporangium. Usually the amount of nutriment
contained in the zygospore is exhausted by the formation of the
terminal sporangium, according to Brefeld;[D] but Van Tieghem and Le
Monnier remark that in their examinations they have often seen a
partition formed at about a third of the length of the principal
filament from the base, below which a strong branch is given off, and
this is also terminated by a large sporangium.

[Illustration: FIG. 96.--Zygospore of _Rhizopus_ in different stages. (De
Bary.)]

De Bary has given a precise account of the formation of the zygospore
in another of the Mucors, _Rhizopus nigricans_, in which he says that
the filaments which conjugate are solid rampant tubes, which are
branched without order and confusedly intermingled. Where two of these
filaments meet each of them pushes towards the other an appendage
which is at first cylindrical and of the same diameter. From the first
these two processes are applied firmly one to the other by their
extremities; they increase in size, become clavate, and constitute
together a fusiform body placed across the two conjugated filaments.
Between the two halves of this body there exists no constant
difference of size; often they are both perfectly equal. In each
there is collected an abundance of protoplasm, and when they have
attained a certain development the largest extremity of each is
isolated by a septum from the clavule, which thus becomes the support
or suspender of the copulative cell. The two conjugated cells of the
fusiform body are generally unequal; the one is a cylinder as long as
it is broad, the other is disciform, and its length is only equal to
half its breadth. The primitive membrane of the clavule forms between
the copulative cells a solid partition of two membranes, but soon
after the cells have become defined the medial partition becomes
pierced in the centre, and then soon entirely disappears, so that the
two twin cells are confounded in one single zygospore, which is due to
the union of two more or less similar utricles. After its formation
the zygospore still increases considerably in size, and acquires a
diameter of more than one-fifth of a millimetre. Its form is generally
spherical, and flattened on the faces which are united to the
suspenders, or it resembles a slightly elongated cask. The membrane
thickens considerably, and consists at the time of maturity of two
superposed integuments; the exterior or epispore is solid, of a dark
blackish-blue colour, smooth on the plane faces in contact with the
suspenders, but covered everywhere else with thick warts, which are
hollow beneath. The endospore is thick and composed of several layers,
colourless, and covered with warts, which correspond and fit into
those of the epispore. The contents of the zygospore are a coarsely
granular protoplasm, in which float large oleaginous drops. While the
zygospore is increasing in size, the suspender of the smaller
copulative cell becomes a rounded and stipitate utricle, often divided
at the base by a septum, and which attains almost to the size of the
zygospore. The suspender of the larger copulative cell preserves its
primitive form and becomes scarcely any larger. It is rare that there
is not a considerable difference of size between the two conjugated
cells and the suspenders.[E]

Similar conjugation with like results also takes place in _Syzygites
megalocarpus_. In this species the germination of the zygospores has
been observed. If, after a certain time of repose, these bodies are
placed on a moist substratum, they emit a germ-like tube, which,
without originating a proper mycelium, develops at the expense of the
nutritive material stored in the zygospore into a carpophore or fruit
bearer, which is many times dichotomously branched, bearing terminal
sporangia characteristic of the species.

It has already been remarked by us that the _Saprolegnei_ are claimed
by some authors as Algæ, whilst we are more disposed to regard them as
closely allied to the Mucors, and as they exhibit in themselves strong
evidence in support of the existence of sexual reproduction, we cannot
forbear giving a summary of what has been observed by De Bary and
others in this very interesting and singular group of plants, to which
M. Cornu has recently dedicated an exhaustive monograph.[F]

In _Saprolegnia monoica_, and others, the female organs consist of
oogonia--that is to say, of cells which are at first globose and rich
in plastic matter, which most generally terminate short branches of
the mycelium, and which are rarely seen in an interstitial position.
The constitutive membrane of the adult oogonia is reabsorbed in a
great many points, and is there pierced with rounded holes. At the
same time the plasma is divided into a larger or smaller number of
distinct portions, which are rounded into little spheres, and separate
from the walls of the conceptacle in order to group themselves at the
centre, where they float in a watery fluid. These gonospheres are then
smooth and bare, with no membrane on their surface of the nature of
cellulose.

[Illustration: FIG. 97.--Conjugation in _Achlya racemosa_. (Cornu.)]

During the formation of the oogonia there arise from its pedicel
or from neighbouring filaments slight cylindrical curved branches,
sometimes turned round the support of the oogonia, and which all tend
towards this organ. Their superior extremity is intimately applied
to its wall, then ceases to be elongated, becomes slightly inflated,
and is limited below by a partition; it is then an oblong cell,
slightly curved, filled with protoplasm, and intimately applied to
the oogonia--in fact, an antheridium or organ of the male sex.
Each oogonium possesses one or several antheridia. Towards the time
when the gonospheres are formed it may be observed that each
antheridium sends to the interior of the oogonia one or several
tubular processes, which have crossed its side wall, and which open
at their extremity in order to discharge their contents. These,
while they are flowing out, present some very agile corpuscles, and
which, considering their resemblance to those in _Vaucheria_, to
which the name of spermatozoids are applied, ought to be considered
as the fecundating corpuscles. After the evacuation of the antheridia
the gonospheres are found to be covered with cellulose; they then
constitute so many oospores, with solid walls. De Bary considers
that, bearing in mind analogous phenomena observed in _Vaucheria_, and
the direct observations of Pringsheim,[G] the cellulose membrane on
the surface of the gonospheres is only the consequence of a sexual
fecundation.

In _Achlya dioica_ the antheridium is cylindrical, the plasma which it
encloses is divided into particles, which attain nearly the size of
the zoospores of the same plant. These particles become globose
cells, grouped in the centre of the antheridium. Afterwards the
contents of these latter cells become divided into numerous bacillary
spermatozoids, which first break the wall of their mother cell, and
then issue from the antheridium. These rod-like corpuscles, which
resemble the spermatozoids in _Vaucheria_, have their movements
assisted by a long cilium. It is presumable that here, as in the
Algæ, the spermatozoids introduce themselves into the cavity of
the oogonium, and unite with the gonospheres.

Amongst obscure and doubtful bodies are those described by Pringsheim,
which have their origin in thick filaments or tubes, similar to those
which form the zoosporangia, and represent so many distinct little
masses of plasma within an homogeneous parietal ganglion. The contour
of these plastic masses is soon delineated in a more precise manner.
We see in their interior some homogeneous granules, which are at first
globose, then oval, and finally travel to the enlarged and ampullæform
extremity of the generating tube. There they become rounded or oval
cells covered with cellulose, and emit from their surface one or
several cylindrical processes, which elongate towards the wall of the
conceptacle, and pierce it, without, however, ever projecting very far
beyond it. At the same time the lacunose protoplasm of each cell
becomes divided into a number of corpuscles, which escape by the open
extremity of the cylindrical neck. They resemble in their organization
and agility the spermatozoids of _Achlya dioica_. They soon become
motionless in water, and do not germinate. During the development of
these organs, the protoplasm of the utricle which contains them offers
at first completely normal characteristics, and disappears entirely by
degrees as they increase. De Bary and Pringsheim believe that these
organs constitute the antheridia of the species of _Saprolegnia_ to
which they belong.

The oospores of the _Saprolegniæ_, when arrived at maturity, possess a
tolerably thick double integument, consisting of an epispore and an
endospore. After a considerable time of repose they give rise to
tubular or vesicular germs, which, without being much elongated,
produce zoospores.[H]

De Bary has claimed for the oogonia in _Cystopus_ and _Peronospora_ a
kind of fecundation which deserves mention here.[I] These same fruits,
he says, which owe their origin to sexual organs, should bear the
names of _oogonia_ and _antheridia_, according to the terminology
proposed by Pringsheim for analogous organs in the Algæ. The formation
of the oogonia, or female organs, commences by the terminal or
interstitial swelling of the tubes of the mycelium, which increase and
take the form of large spherical or oboval cells, and which separate
themselves by septa from the tube which carries them. Their membrane
encloses granules of opaque protoplasm, mingled with numerous bulky
granules of colourless fatty matter.

[Illustration: FIG. 98.--Conjugation in _Peronospora; a. antheridium_.
(De Bary.)]

The branches of the mycelium which do not bear oogonia apply their
obtuse extremities against the growing oogonia; this extremity swells,
and, by a transverse partition, separates itself from the supporting
tube. It is the antheridium, or male organ, which is formed by this
process; it takes the form of an obliquely clavate or obovate cellule,
which is always considerably smaller than the oogonium, and adheres to
its walls by a plane or convex area. The slightly thickened membrane
of the antheridia encloses protoplasm which is finely granular. It is
seldom that more than one antheridium applies itself to an oogonium.

The two organs having together achieved their development, the large
granules contained in the oogonium accumulate at its centre to group
themselves under the form of an irregular globule deprived of a proper
membrane, and surrounded by a bed of almost homogeneous protoplasm.
This globule is the _gonosphere_, or reproductive sphere, which,
through the means of fecundation, should become the reproductive
body, vegetable egg, or oospore. The gonosphere having been formed,
the antheridium shoots out from the centre of its face, close against
the oogonium, a straight tube, which perforates the walls of the
female cell, and traversing the protoplasm of its periphery, directs
itself to the gonosphere. It ceases to elongate itself as soon as it
touches it, and the gonosphere becomes clothed with a membrane of
cellulose, and takes a regular spheroidal form.

[Illustration: FIG. 99.--Antheridia and oogonium of _Peronospora_. (De
Bary.)]

Considering the great resemblance of these organs with the sexual
organs of the Saprolegniæ, which are closely allied to the Algæ, and
of which the sexuality has been proved, De Bary adds, we have no doubt
whatever that the phenomena just described represent an act of
fecundation, and that the tube pushed out by the antheridium should be
regarded as a fecundating tube. It is remarkable that amongst these
fungi the tube projected by the antheridium effects fecundation only
by contact. Its extremity never opens, and we never find antherozoids;
on the contrary, the antheridium presents, up to the maturity of the
oospore, the appearance which it presented at the moment of
fecundation.

The primitive membrane of the oospore, at first very thin, soon
acquires a more sensible thickness, and becomes surrounded by an
external layer (epospore), which is formed at the expense of the
protoplasm of the periphery. This disappears in proportion as the
epispore attains maturity, and finally there only remains a quantity
of granules, suspended in a transparent watery fluid. At the period of
maturity, the epispore is a slightly thickened, resistant membrane, of
a yellowish-brown colour, and finely punctate. The surface is almost
always provided with brownish warts, which are large and obtuse,
sometimes isolated, and sometimes confluent, forming irregular crests.
These warts are composed of cellulose, which reagents colour of a deep
blue, whilst the membrane which bears them preserves its primitive
colour. One of the warts, larger than the rest, and recognizable by
its cylindrical form, always forms a kind of thick sheath around the
fecundating tube. The ripe endospore is a thick, smooth, colourless
membrane, composed of cellulose containing a bed of finely granulated
protoplasm, which surrounds a great central vacuole. This oospore, or
resting spore, may remain dormant in this state within the tissues of
the foster plant for some months. Its ultimate development by
production of zoospores is similar to the production of zoospores from
conidia, which it is unnecessary to repeat here. The oospore becomes
an oosporangium, and from it at least a hundred germinating bodies are
at length expelled.

Amongst the principal observers of certain phenomena of copulation in
cells formed in the earliest stages of the _Discomycetes_ are
Professor de Bary,[J] Dr. Woronin,[K] and Messrs. Tulasne.[L] In the
_Ascobolus pulcherrimus_ of Crouan, Woronin ascertained that the cup
derives its origin from a short and flexible tube, thicker than the
other branches of the mycelium, and which is soon divided by
transverse septa into a series of cells, the successive increase of
which finally gives to the whole a torulose and unequal appearance.
The body thus formed he calls a "vermiform body." The same observer
also seems to have convinced himself that there exists always in
proximity to this body certain filaments, the short arched or
inflected branches of which, like so many antheridia, rest their
anterior extremities on the utriform cells. This contact seems to
communicate to the vermiform body a special vital energy, which is
immediately directed towards the production of a somewhat filamentous
tissue, on which the hymenium is at a later period developed. This
"vermiform body" of M. Woronin has since come to be recognized under
the name of "scolecite."

Tulasne observes that this "scolecite" or ringed body can be readily
isolated in _Ascobolus furfuraceus_. When the young receptacles are
still spherical and white, and have not attained a diameter exceeding
the one-twentieth of a millimetre, it is sufficient to compress them
slightly in order to rupture them at the summit and expel the
"scolecite." This occupies the centre of the little sphere, and is
formed of from six to eight cells, curved in the shape of a comma.

In _Peziza melanoloma_, A. and S., the same observer succeeded still
better in his searches after the scolecite, which he remarks is in
this species most certainly a lateral branch of the filaments of the
mycelium. This branch is isolated, simple, or forked at a short
distance from its base, and in diameter generally exceeding that of
the filament which bears it. This branch is soon arcuate or bent, and
often elongated in describing a spiral, the irregular turns of which
are lax or compressed. At the same time its interior, at first
continuous, becomes divided by transverse septa into eight or ten or
more cells. Sometimes this special branch terminates in a crozier
shape, which is involved in the bent part of another crozier which
terminates a neighbouring filament. In other cases the growing branch
is connected, by its extremity, with that of a hooked branch. These
contacts, however, did not appear to Tulasne to be so much normal as
accidental. But of the importance of the ringed body, or "scolecite,"
there was no room for doubt, as being the certain and habitual
rudiment of the fertile cup. In fact, inferior cells are produced from
the flexuous filaments which creep about its surface, cover and
surround it on all sides, while joining themselves to each other. At
first continuous, then septate, these cells by their union constitute
a cellular tissue, which increases little by little until the
scolecite is so closely enveloped that only its superior extremity can
be seen. These cellular masses attain a considerable volume before the
hymenium begins to show itself in a depression of their summit. So
long as their smallness permits of their being seen in the field of
the microscope, it can be determined that they adhere to a single
filament of the mycelium by the base of the scolecite which remains
naked.

Although Tulasne could not satisfy himself of the presence of any act
of copulation in _Ascobolus furfuraceus_, or _Peziza melanoloma_, he
was more successful with _Peziza omphalodes_. As early as 1860 he
recognized the large globose, sessile, and grouped vesicles which
originate the fertile tissue, but did not comprehend the part which
these macrocysts were to perform. Each of these emits from its summit
a cylindrical tube, generally flexuous, but always more or less bent
in a crozier shape, sometimes attenuated at the extremity. Thus
provided, these utricles resemble so many tun-shaped, narrow-necked
retorts, filled with a granular thick roseate protoplasm. In the
middle of these, and from the same filaments, are generated elongated
clavate cells, with paler contents, more vacuoles, which Tulasne names
_paracysts_. These, though produced after the _macrocysts_, finally
exceed them in height, and seem to carry their summit so as to meet
the crozier-like prolongations. It would be difficult to determine to
which of these two orders of cells belongs the initiative of
conjugation. Sometimes the advance seems to be on one side, and
sometimes on the other. However this may be, the meeting of the
extremity of the connecting tube with the summit of the neighbouring
paracyst is a constant fact, observed over and over again a hundred
times. There is no real junction between the dissimilar cells above
described, except at the very limited point where they meet, and there
a circular perforation may be discerned at the end, defined by a round
swelling, which is either barely visible or sometimes very decided.
Everywhere else the two organs may be contiguous, or more or less near
together, but they are free from any adherence whatever. If the
plastic matters contained in the conjugated cells influence one
another reciprocally, no notable modification in their appearance
results at first. The large appendiculate cell seems, however, to
yield to its consort a portion of the plasma it contains. One thing
only can be affirmed from these phenomena, that the conjugated cells,
especially the larger, wither and empty themselves, while the upright
compressed filaments, which will ultimately constitute the asci,
increase and multiply.[M]

[Illustration: FIG. 100.--Conjugation in _Peziza omphalodes_. (Tulasne.)]

[Illustration: FIG. 100a.--Formation of conceptacle in _Erysiphe_.]

Certain phenomena concerned in the development of the _Erysiphei_ belong
also to this connection. The mycelium of _Erysiphe cichoracearum_, like
that of other species, consists of branched filaments, crossed in all
directions, which adhere as they climb to the epidermis of the plant on
which the fungus lives as a parasite. The perithecia are engendered
where two filaments cross each other. These swell slightly at this
point, and each emits a process which imitates a nascent branch, and
remains upright on the surface of the epidermis. The process
originating from the inferior filament soon acquires an oval form and
a diameter double that of the filament; then it becomes isolated from
it by a septum, and constitutes a distinct cell, which De Bary[N]
terms an oocyst. The appendage which proceeds from the inferior filament
always adheres intimately to this cell, and elongates into a slender
cylindrical tube, which terminates in an obtuse manner at the summit
of the same cell. At its base it is also limited by a septum, and soon
after another appears a little below its extremity at a point
indicated beforehand by a constriction. This new septum defines a
terminal short obtuse cell, the antheridium, which is thus borne on a
narrow tube like a sort of pedicel. Immediately after the formation of
the antheridia new productions show themselves, both around the oocyst
and within it. Underneath this cell eight or ten tubes are seen to
spring from the filament which bears it; these join themselves by the
sides to each other and to the pedicel of the antheridium, while they
apply their inner face to the oocyst, above which their extremities soon
meet. Each of the tubes is then divided by transverse septa into two
or three distinct cells, and in this manner the cellular walls of the
perithecia come into existence.

During this time the oocyst enlarges and divides, without its being
possible precisely to determine the way in which it happens, into a
central cell and an outer layer, ordinarily simple, of smaller
cells, contiguous to the general enveloping wall. The central cell
becomes the single ascus, which is characteristic of the species,
and the layer which surrounds it constitutes the inner wall of its
perithecium. The only changes afterwards observed are the increase
in size of the perithecium, the production of the root-like filaments
which proceed from its outer wall, the brown tint which it assumes,
and finally the formation of the sporidia in the ascus. The
antheridium remains for a long time recognizable without undergoing
any essential modification, but the dark colour of the perithecium
soon hides it from the observer's eye. De Bary thinks that he is
authorized in assuming the probability that the conceptacles and
organs of fructification of others of the _Ascomycetes_, including
the _Discomycetes_ and the _Tuberacei_, are the results of sexual
generation.

Certain phenomena which have been observed amongst the _Coniomycetes_
are cited as examples of sexual association. Amongst these may be
named the conjugation of the slender spores of the first generation,
produced on the germinating threads of _Tilletia_,[O] and similar
acts of conjugation, as observed in some species of _Ustilago_.
Whether this interpretation should be placed on those phenomena in the
present condition of our knowledge is perhaps an open question.

[Illustration: FIG. 101.--_Tilletia caries_ with conjugating cells.]

Finally, the spermogonia must be regarded as in some occult manner,
which as yet has baffled detection, influencing the perfection of
sporidia[P] In _Rhytisma_, found on the leaves of maple and willow,
black pitchy spots at first appear, which contain within them a golden
pulp, in which very slender corpuscles are mixed with an abundant
mucilage. These corpuscles are the spermatia, which in _Rhytisma
acerinum_ are linear and short, in _Rhytisma salicinum_ globose. When
the spermatia are expelled, the stroma thickens for the production of
asci and sporidia, which are afterwards developed during the autumn
and winter.

Several of the species of _Hysterium_ also possess spermogonia,
notably _H. Fraxini_, which may be distinguished from the ascigerous
perithecia with which they are associated by their smaller size and
flask-like shape. From these the spermatia are expelled long before
the maturity of the spores. In _Hypoderma virgultorum_, _H.
commune_, and _H. scirpinum_, the spermogonia are small depressed
black capsules, which contain an abundance of minute spermatia.
These were formerly regarded as distinct species, under the name of
_Leptostroma_. In _Stictis ocellata_ a great number of the tubercles
do not pass into the perfect state until after they have produced
either linear, very short spermatia, or stylospores, the latter
being reproductive bodies of an oblong shape, equal in size to the
perfect sporidia. Some of the tubercles never pass beyond this stage.

Again, there is a very common fungus which forms black discoid spots
on dead holly leaves, called _Ceuthospora phacidioides_, figured by
Greville in his "Scottish Cryptogamic Flora," which expels a profusion
of minute stylospores; but later in the season, instead of these, we
find the asci and sporidia of _Phacidium ilicis_, so that the two are
forms and conditions the one of the other.

In _Tympanis conspersa_ the spermogonia are much more commonly met
with than the complete fruit. There is a great external resemblance in
them to the ascigerous cups, but there is no evidence that they are
ever transformed into such. The perfect sporidia are also very minute
and numerous, being contained in asci borne in cups, which usually
surround the spermogonia.

In several species of _Dermatea_ the stylospores and spermatia
co-exist, but they are disseminated before the appearance of the
ascigerous receptacles, yet they are produced upon a common stroma not
unlike that of _Tubercularia_.

In its early stage the common and well-known _Bulgaria inquinans_,
which when mature looks like a black _Peziza_, is a little tubercle,
the whole mass of which is divided into ramified lobes, the
extremities of which become, towards the surface of the tubercle,
receptacles from whence escape waves of spermatia which are
colourless, or stylospores mixed with them which are larger and nearly
black.

Amongst the _Sphæriacei_ numerous instances might be cited of minute
stylosporous bodies in consort with, or preceding, the ascigerous
receptacles. A very familiar example may be found at the base of old
nettle stems in what has been named _Aposphæria acuta_, but which
truly are only the stylospores of the _Sphæria coniformis_, the
perithecia of which flourish in company or in close proximity to them.
Most of these bodies are so minute, delicate, and hyaline that the
difficulties in the way of tracing them in their relations to the
bodies with which they are associated are very great. Nevertheless
there is strong presumption in favour of regarding some of them as
performing the functions which the name applied to them indicates.

Professor de Bary cautiously refrains from accepting spermatia other
than as doubtful or at least uncertain sexual bodies.[Q] He says that
the Messrs. Tulasne have supposed that the spermogonia represented the
male sex, and that the spermatia were analogous to spermatozoids.
Their opinion depends on two plausible reasons,--the spermatia, in
fact, do not germinate, and the development of the spermogonia
generally precedes the appearance of the sporophorous organs, a double
circumstance which reminds us of what is known of the spermatozoids
and antheridia of other vegetables. It remained to discover which were
the female organs which underwent fecundation from the spermatia.

Many organs placed at first amongst spermatia have been recognized by
M. Tulasne as being themselves susceptible of germination, and
consequently ought to take their place among legitimate spores. Then
it must be considered that very many spores can only germinate under
certain conditions. It is, therefore, for the present a doubtful
question whether there exist really any spermatia incapable of
germination, or if the default of germination of these corpuscles does
not rather depend on the experiments hitherto attempted not having
included the conditions required by the phenomena. Moreover, as yet no
trace has been discovered of the female organs which are specially
fecundated by the spermatia.

Finally, there exist in the _Ascomycetes_ certain organs of
reproduction, diverse spore-bearing apparatus, pycnidia, and others,
which, like the spermogonia, usually precede ascophorous fruits. The
real nature of the spermogonia and spermatia should therefore be
regarded as, at present, very uncertain; as regards, however, the
spermatia which have never been seen to germinate, perhaps it is as
well not to absolutely reject the first opinion formed concerning
them, or perhaps they might be thought to perform the part of
androspores, attributing to that expression the meaning which
Pringsheim gives it in the _Conferoæ_. The experiments performed with
the spermatia which do not germinate, and with the spermogonia of the
Uredines, do not, at any rate, appear to justify the reputed masculine
or fecundative nature of these organs. The spermogonia constantly
accompany or precede fruits of _Æcidium_, whence naturally follows the
presumption that the first are in a sexual relation to the second.
Still, when Tulasne cultivated _Endophyllum sempervivum_, he obtained
on some perfectly isolated rosettes of _Sempervivum_ some _Æcidium_
richly provided with normal and fertile spores, without any trace of
spermogonia or of spermatia.

   [A] M. Tulasne has devoted a chapter to the spermogonia of the
       Uredines in his memoir, to which we have already alluded.

   [B] Oeersted, in "Verhandl der König. Dän. Gesell. Der Wissensch,"
       1st January, 1865; De Bary, "Handbuch der Physiol. Botanik"
       (1866), p. 172; "Annales des Sci. Nat." (5^me sér.), vol. v.
       (1866), p. 366.

   [C] Van Tieghem and Le Monnier, in "Annales des Sci. Nat." (1873),
       vol. xvii. p. 261.

   [D] Brefeld, "Bot. Unt. uber Schimmelpilze," p. 31.

   [E] De Bary, "Morphologie und Physiologie der Pilze," cap. 5, p. 160;
       "Ann. des Sci. Nat." (1866), p. 343.

   [F] Cornu, in "Ann. des Sci. Nat." (5^me sér.), vol. xv. p. 1
       (1872).

   [G] Pringsheim's "Jahrbucher," vol. ii. p. 169.

   [H] De Bary, in "Annales des Sciences Naturelles" (5^me sér.), vol.
       v. (1866), p. 343; Hoffmeister's "Handbook" (Fungi), cap. v. p.
       155.

   [I] De Bary, in "Annales des Sci. Nat." (4^me sér.), vol. xx. p.
       129.

   [J] De Bary, in "Annales des Sciences Naturelles" (5^me sér.), p.
       343.

   [K] Woronin, in De Bary's "Beitr. zur. Morph. und Physiol. der
       Pilze," ii. (1866), pp. 1-11.

   [L] Tulasne, "Ann. des Sci. Nat." (5^me sér.), October, 1866, p.
       211.

   [M] Tulasne, "On the Phenomena of Copulation in certain Fungi," in
       "Ann. des Sci. Nat." (1866), p. 211.

   [N] De Bary, "Morphologie und Phys. der Pilze," cap. v., p. 162.

   [O] Berkeley, in "Journ. Hort. Soc." vol ii. p. 107; Tulasne, "Ann.
       d. Sc. Nat." (4^me sér.), vol. ii. tab. 12.

   [P] Tulasne, "New Researches on the Reproductive Apparatus of Fungi;"
       "Comptes Rendus," vol. xxxv. (1852), p. 841.

   [Q] De Bary, "Morphologie und Physiologie der Pilze," cap. v. p.
       168.



IX.

POLYMORPHISM.


A great number of very interesting facts have during late years been
brought to light of the different forms which fungi assume in the
course of their development. At the same time, we fear that a great
many assumptions have been accepted for fact, and supposed connections
and relations between two or three or more so-called species,
belonging to different genera, have upon insufficient data been
regarded as so many states or conditions of one and the same plant.
Had the very pertinent suggestions of Professor de Bary been more
generally acted upon, these suspicions would have been baseless. His
observations are so valuable as a caution, that we cannot forbear
prefacing our own remarks on this subject by quoting them.[A] In order
to determine, he says, whether an organic form, an organ, or an
organism, belongs to the same series of development as another, or
that which is the same is developed from it, or _vice versâ_, there is
only one way, viz., to observe how the second grows out of the first.
We see the commencement of the second begin as a part of the first,
perfect itself in connection with it, and at last it often becomes
independent; but be it through spontaneous dismembering from the
first, or that the latter be destroyed and the second remains, both
their disunited bodies are always connected together in organic
continuity, as parts of a whole (single one) that can cease earlier or
later.

By observing the organic continuity, we know that the apple is the
product of development of an apple-tree, and not hung on it by
chance, that the pip of an apple is a product of the development of
the apple, and that from the pip an apple-tree can at last be
developed, that therewith all these bodies are members of a sphere of
development or form. It is the same with every similar experience of
our daily life, that where an apple-tree stands, many apples lie on
the ground, or that in the place where apple-pips are sown seedlings,
little apple-trees, grow out of the ground, is not important to our
view of the course of development. Every one recognizes that in his
daily life, because he laughs at a person who thinks a plum which
lies under an apple-tree has grown on it, or that the weeds which
appear among the apple seedlings come from apple-pips. If the
apple-tree with its fruit and seed were microscopically small, it
would not make the difference of a hair's breadth in the form of the
question or the method of answering it, as the size of the object
can be of no importance to the latter, and the questions which
apply to microscopical fungi are to be treated in the same manner.

If it then be asserted that two or several forms belong to a series of
development of one kind, it can only be based on the fact of their
organic continuity. The proof is more difficult than in large plants,
partly because of the delicacy, minuteness, and fragility of the
single parts, particularly the greater part of the mycelia, partly
because of the resemblance of the latter in different species, and
therefore follows the danger of confusing them with different kinds,
and finally, partly in consequence of the presence of different kinds
in the same substratum, and therefore the mixture not only of
different sorts of mycelia, but also that different kinds of spores
are sown. With some care and patience, these difficulties are in no
way insurmountable, and they must at any rate be overcome; the organic
continuity or non-continuity must be cleared up, unless the question
respecting the course of development, and the series of forms of
special kinds, be laid on one side as insolvable.

Simple and intelligible as these principles are, they have not always
been acted upon, but partly neglected, partly expressly rejected, not
because they were considered false, but because the difficulties of
their application were looked upon as insurmountable. Therefore
another method of examination was adopted; the spores of a certain
form were sown, and sooner or later they were looked after to see what
the seed had produced--not every single spore--but the seed _en
masse_, that is, in other words, what had grown on that place where
the seed had been sown. As far as it relates to those forms which are
so widely spread, and above all grow in conjunction with one
another--and that is always the case in the specimens of which we
speak--we can never be sure that the spores of the form which we mean
to test are not mingled with those of another species. He who has made
an attentive and minute examination of this kind knows that we may be
sure to find such a mixture, and that such an one was there can be
afterwards decidedly proved. From the seed which is sown, these
spores, for which the substratum was most suitable, will more easily
germinate, and their development will follow the more quickly. The
favoured germs will suppress the less favoured, and grow up at their
expense. The same relation exists between them as between the seeds,
germs, and seedlings of a sown summer plant, and the seeds which have
been undesignedly sown with it, only in a still more striking manner,
in consequence of the relatively quick development of the mildew
fungus.

Therefore, that from the latter a decided form, or a mixture of
several forms, is to be found sown on one spot, is no proof of
their generic connection with one which has been sown for the
purpose of experiments; and the matter will only be more confused
if we call imagination to our aid, and place the forms which are
found near one another, according to a real or fancied resemblance,
in a certain series of development. All those statements on the
sphere of form and connection, which have for their basis such a
superficial work, and are not based on the clear exposition of the
continuity of development, as by the origin of the connection of
the _Mucor_ with _Penicillium_, _Oidium lactis_ and _Mucor_, _Oidium_
and _Penicillium_, are rejected as unfounded.

A source of error, which can also interfere in the last-named
superficial method of cultivation for experiments, is, viz., that
heterogeneous unwished-for spores intrude themselves from without,
among the seed which is sown, but that has been until now quite
disregarded. It is of great importance in practice, but in truth, for
our present purpose, synonymous with what we have already written.
Those learned in the science of this kind of culture lay great stress
on its importance, and many apparatuses have been constructed, called
"purely cultivating machines," for the purpose of destroying the
spores which are contained in the substratum, and preventing the
intrusion of those from without. The mixture in the seed which is sown
has of course not been obviated. These machines may, perhaps, in every
other respect, fulfil their purpose, but they cannot change the form
of the question, and the most ingeniously constructed apparatus cannot
replace the attention and intellect of the observer.[B]

Two distinct kinds of phenomena have been grouped under the term
"polymorphy." In one series two or more forms of fruit occur
consecutively or simultaneously on the same individual, and in the
other two or more forms appear on a different mycelium, on a different
part of the same plant, or on a matrix wholly distinct and different;
in the latter case the connection being attested or suspected
circumstantially, in the former proved by the method suggested by De
Bary. It will at once be conceded that in cases where actual growth
and development substantiate the facts the polymorphy is undoubted,
whilst in the other series it can at best be little more than
suspected. We will endeavour to illustrate both these series by
examples.

One of the first and earliest suspected cases of dualism, which long
puzzled the older mycologists, was observed amongst the Uredines, and
many years ago it was held that there must be some mysterious
association between the "red rust" (_Trichobasis ruligo vera_) of
wheat and grasses and the "corn mildew" (_Puccinia graminis_) which
succeeded it. The simple spored rust first makes its appearance, and
later the bilocular "mildew." It is by no means uncommon to find the
two forms in the same pustule. Some have held, without good reason,
that the simple cells became afterwards divided and converted into
_Puccinia_, but this is not the case; the uredo-spores are always
simple, and remain so except in _Uredo linearis_, where every
intermediate stage has been observed. Both are also perfect in their
kind, and capable of germination.

What the precise relations between the two forms may be has as yet
never been revealed to observers, but that the two forms belong to one
species is not now doubted. Very many species of _Puccinia_ have
already been found associated with a corresponding _Trichobasis_, and
of _Phragmidium_ with a relative _Lecythea_, but it may be open to
grave doubt whether some of the very many species associated by
authors are not so classed upon suspicion rather than observation. We
are ready to admit that the evidence is strong in favour of the
dimorphism of a large number of species--it _may_ be in all, but this
awaits proof, or substantial presumption on good grounds. Up to the
present we know that there are species of _Trichobasis_ which have
never been traced to association with a _Puccinia_, and doubtless
there will be species of _Puccinia_ for which no corresponding _Uredo_
or _Trichobasis_ can be found.

Tulasne remarks, in reference to _Puccinia sonchi_, in one of his
memoirs, that this curious species exhibits, in effect, that a
_Puccinia_ may unite three sorts of reproductive bodies, which, taking
part, constitute for the mycologists of the day three entirely
different plants--a _Trichobasis_, a _Uromyces_, and a _Puccinia_. The
Uredines are not less rich, he adds, in reproductive bodies of divers
sorts than the _Pyrenomycetes_ and the _Discomycetes_; and we should
not be surprised at this, since it seems to be a law, almost constant
in the general harmony of nature, that the smaller the organized
beings are, the more their races are prolific.

In _Puccinia variabilis_, Grev., it is common to find a unicellular
form, species of _Trichobasis_, in the same pustules. A like
circumstance occurs with _Puccinia violarum_, Link., and _Trichobasis
violarum_, B.; with _Puccinia fallens_, C., and _Trichobasis fallens_,
Desm.; also with _Puccinia menthæ_, P., and _Trichobasis Labiatarum_,
D. C. In _Melampsora_, again, the prismatic pseudospores of
_Melampsora salicina_, Lev., are the winter fruits of _Lecythea
caprearum_, Lev., as those of _Melampsora populina_, Lev., are of
_Lecythea populina_, Lev. In the species of _Lecythea_ themselves will
be found, as De Bary[C] has shown, hyaline cysts of a larger size,
which surround the pseudospores in the pustules in which they are
developed.

A good illustration of dimorphism in one of the commonest of moulds is
given by De Bary in a paper from which we have already quoted.[D] He
writes thus:--In every household there is a frequent unbidden guest,
which appears particularly on preserved fruits, viz., the _mould_
which is called _Aspergillus glaucus_. It shows itself to the naked
eye as a woolly floccy crust over the substance, first purely white,
then gradually covered with little fine glaucous, or dark green dusty
heads. More minute microscopical examination shows that the fungus
consists of richly ramified fine filaments, which are partly
disseminated in the substratum, and partly raised obliquely over it.
They have a cylindrical form with rounded ends, and are divided into
long outstretched members, each of which possesses the property which
legitimatizes it as a vesicle in the ordinary sense of the word; it
contains, enclosed within a delicate structureless wall, those bodies
which bear the appearance of a finely granulated mucous substance,
which is designated by the name of protoplasm, and which either
equally fills the cells, or the older the cell the more it is filled
with watery cavities called vacuoles.

All parts are at first colourless. The increase in the length of the
filaments takes place through the preponderating growth near their
points; these continually push forward, and, at a short distance from
them, successive new partitions rise up, but at a greater distance,
the growth in the length ceases. This kind of growth is called point
growth. The twigs and branches spring up as lateral dilatations of
the principal filament, which, once designed, enlarges according to
the point growth. This point growth of every branch is, to a certain
extent, unlimited. The filaments in and on the substratum are the
first existing members of the fungus; they continue so long as it
vegetates. As the parts which absorb nourishment from and consume the
substance, they are called the _mycelium_. Nearly every fungus
possesses a mycelium, which, without regard to the specific difference
of form and size, especially shows the described nature in its
construction and growth.

The superficial threads of the mycelium produce other filaments beside
those numerous branches which have been described, and which are the
fruit thread (carpophore) or conidia thread. These are on an average
thicker than the mycelium threads, and only exceptionally ramified or
furnished with partitions; they rise almost perpendicularly into the
air, and attain a length of, on an average, half a millimetre, or
one-fiftieth of an inch, but they seldom become longer, and then their
growth is at an end. Their free upper end swells in a rounded manner,
and from this is produced, on the whole of its upper part, rayed
divergent protuberances, which attain an oval form, and a length
almost equal to their radius, or, in weaker specimens, the diameter of
the rounded head. The rayed divergent protuberances are the direct
producers and bearers of the propagating cells, spores, or conidia,
and are called sterigmata. Every sterigma at first produces at its
point a little round protuberance, which, with a strong narrow basis,
rests upon the sterigma. These are filled with protoplasm, swell more
and more, and, after some time, separate themselves by a partition
from the sterigma into independent cells, spores, or conidia.

The formation of the first spore takes place at the same end of the
sterigma, and in the same manner a second follows, then a third, and
so on; every one which springs up later pushes its predecessor in the
direction of the axis of the sterigma in the same degree in which it
grows itself; every successive spore formed from a sterigma remains
for a time in a row with one another. Consequently every sterigma
bears on its apex a chain of spores, which are so much the older, the
farther they stand from the sterigma. The number of the links in a
chain of spores reaches in normal specimens to ten or more. All
sterigmata spring up at the same time, and keep pace with one another
in the formation of the spores. Every spore grows for a time,
according to its construction, and at last separates itself from its
neighbours. The mass of dismembered spores forms that fine glaucous
hue which is mentioned above. The spores, therefore, are articulated
in rows, one after the other, from the ends of the sterigmata. The
ripe spore, or conidium, is a cell of a round or broadly oval form,
filled with a colourless protoplasm, and, if observed separately, is
found to be provided with a brownish, finely verruculose, dotted
wall.

[Illustration: FIG. 102.--_a._ _Aspergillus glaucus_; _b._ conidia; _c._
germinating conidium; _d._ conceptacle of _Eurotium_; _e._ ascus.]

The same mycelium which forms the pedicel for the conidia when it is
near the end of its development, forms by normal vegetation a second
kind of fructification. It begins as delicate thin little branches,
which are not to be distinguished by the naked eye, and which mostly
in four or six turns, after a quickly terminated growth, wind their
ends like a corkscrew. (Fig. 102.) The sinuations decrease in width
more and more, till they at last reach close to one another, and the
whole end changes from the form of a corkscrew into that of a hollow
screw. In and on that screw-like body, a change of a complicated kind
takes place, which is a productive process. In consequence of this,
from the screw body a globose receptacle is formed, consisting of a
thin wall of delicate cells, and a closely entwined row of cells
surrounded by this dense mass (_d_). By the enlargement of all these
parts the round body grows so much, that by the time it is ripe it is
visible to the naked eye. The outer surface of the wall assumes a
compactness and a bright yellow colour; the greater part of the cells
of the inner mass become asci for the formation of sporidia, while
they free themselves from the reciprocal union, take a broad oval
form, and each one produces within its inner space eight sporidia
(_e_). These soon entirely fill the ascus. When they are quite ripe,
the wall of the conceptacle becomes brittle, and from irregular
fissures, arising easily from contact, the colourless round sporidia
are liberated.

The pedicels of both kinds of fruit are formed from the same mycelium
in the order just described. If we examine attentively, we can often
see both springing up close to one another from the same filament of a
mycelium. This is not very easy in the close interlacing of the stalks
of a mass of fungi in consequence of their delicacy and fragility.
Before their connection was known, the conceptacles and the conidia
pedicels were considered as organs of two very different species of
fungi. The conceptacles were called _Eurotium herbariorum_, and the
conidia bearers were called _Aspergillus glaucus_.

Allied to _Eurotium_ is the group of _Erysiphei_, in which
well-authenticated polymorphy prevails. These fungi are developed
on the green parts of growing plants, and at first consist of a
white mouldy stratum, composed of delicate mycelium, on which erect
threads are produced, which break up into subglobose joints or
conidia. The species on grass was named _Oidium monilioides_
before its relationship was known, but undoubtedly this is only the
conidia of _Erysiphe graminis_. In like manner the vine disease
(_Oidium Tuckeri_) is most probably only the conidia of a species of
_Erysiphe_, of which the perfect condition has not yet been
discovered. On roses the old _Oidium leucoconium_ is but the conidia
of _Sphærotheca pannosa_, and so of other species. The _Erysiphe_
which ultimately appears on the same mycelium consists of globose
perithecia, externally furnished with thread-like appendages, and
internally with asci containing sporidia. In this genus there are
no less than five different forms of fruit,[E] the multiform
threads on the mycelium, already alluded to as forms of _Oidium_, the
asci contained in the sporangia, which is the proper fruit of the
_Erysiphe_, larger stylospores which are produced in other
sporangia, the smaller stylospores which are generated in the
pycnidia, and separate sporules which are sometimes formed in the
joints of the necklaces of the conidia. These forms are figured in the
"Introduction to Cryptogamic Botany" from _Sphærotheca Castagnei_,
which is the hop mildew.[F] The vine disease, hop mildew, and rose
mildew, are the most destructive species of this group, and the
constant annoyance of cultivators.

[Illustration: FIG. 103.--_Erysiphe cichoracearum._ _a._ Receptacle; _o._
mycelium. (De Bary.)]

When first describing an allied fungus found on old paper, and named
_Ascotricha chartarum_, the Rev. M. J. Berkeley called attention to
the presence of globose conidia attached to the threads which surround
the conceptacles,[G] and this occurred as long since as 1838. In a
recent species of _Chætomium_ found on old sacking, _Chætomium
griseum_, Cooke,[H] we have found tufts in all respects similar
externally to the _Chætomium_, but no perithecium was formed, naked
conidia being developed apparently at the base of the coloured
threads. In _Chætomium funicolum_, Cooke, a black mould was also found
which may possibly prove to be its conidia, but at present there is no
direct evidence.

The brothers Tulasne have made us acquainted with a greater
number of instances amongst the _Sphæriacei_ in which multiple
organs of reproduction prevail. Very often old and decaying
individuals belonging to species of _Boletus_ will be found
filled, and their entire substance internally replaced, by the
threads and multitudinous spores of a golden yellow parasite, to
which the name of _Sepedonium chrysospermum_ has been given.
According to Tulasne, this is merely a condition of a sphæriaceous
fungus belonging to his genus _Hypomyces_.[I]

The same observers also first demonstrated that _Trichoderma viride_,
P., was but the conidia-bearing stage of _Hypocrea rufa_, P., another
sphæriaceous fungus. The ascigerous stroma of the latter is indeed
frequently associated in a very close manner with the cushions of the
pretended _Trichoderma_, or in other cases the same stroma will give
rise to a different apparatus of conidia, of which the principal
elements are acicular filaments, which are short, upright, and almost
simple, and which give rise to small oval conidia which are solitary
on the tips of the threads. Therefore this _Hypocrea_ will possess two
different kinds of conidia, as is the case in many species of
_Hypomyces_.

A most familiar instance of dualism will be found in _Nectria
cinnabarina_, of which the conidia form is one of the most common of
fungi, forming little reddish nodules on all kinds of dead twigs.[J]

[Illustration: FIG. 104.--Twig with _Tubercularia_ on the upper portion,
_Nectria_ on the lower.]

Almost any small currant twig which has been lying on the ground in a
damp situation will afford an opportunity of studying this phenomenon.
The whole surface of the twig will be covered from end to end with
little bright pink prominences, bursting through the bark at regular
distances, scarcely a quarter of an inch apart. Towards one end of the
twig probably the prominences will be of a deeper, richer colour, like
powdered cinnabar. The naked eye is sufficient to detect some
difference between the two kinds of pustules, and where the two merge
into each other specks of cinnabar will be visible on the pink
projections. By removing the bark it will be seen that the pink bodies
have a sort of paler stem, which spreads above into a somewhat globose
head, covered with a delicate mealy bloom. At the base it penetrates
to the inner bark, and from it the threads of mycelium branch in all
directions, confined, however, to the bark, and not entering the woody
tissues beneath. The head, placed under examination, will be found to
consist of delicate parallel threads compacted together to form the
stem and head. Some of these threads are simple, others are branched,
bearing here and there upon them delicate little bodies, which are
readily detached, and which form the mealy bloom which covers the
surface. These are the conidia, little slender cylindrical bodies,
rounded at the ends.

[Illustration: FIG. 105.--Section of _Tubercularia_. _c._ Threads with
conidia.[K]]

Passing to the other bodies, which are of a deeper colour, it will
soon be discovered that, instead of being simple rounded heads, each
tubercle is composed of numerous smaller, nearly globose bodies,
closely packed together, often compressed, all united to a base
closely resembling the base of the other tubercles. If for a moment we
look at one of the tubercles near the spot where the crimson
tubercles seem to merge into the pink, we shall not only find them
particoloured, but that the red points are the identical globose
little heads just observed in clusters. This will lead to the
suspicion, which can afterwards be verified, that the red heads
are really produced on the stem or stroma of the pink tubercles.

A section of one of the red tubercles will show us how much the
internal structure differs. The little subglobose bodies which spring
from a common stroma or stem are hollow shells or capsules, externally
granular, internally filled with a gelatinous nucleus. They are,
indeed, the perithecia of a sphæriaceous fungus of the genus
_Nectria_, and the gelatinous nucleus contains the fructification.
Still further examination will show that this fructification consists
of cylindrical asci, each enclosing eight elliptical sporidia, closely
packed together, and mixed with slender threads called paraphyses.

Here, then, we have undoubted evidence of _Nectria cinnabarina_, with
its fruit, produced in asci growing from the stroma or stem, and in
intimate relationship with what was formerly named _Tubercularia
vulgaris_. A fungus with two forms of fruit, one proper to the pink,
or _Tubercularia_ form, with naked slender conidia, the other proper
to the mature fungus, enclosed in asci, and generated within the walls
of a perithecium. Instances of this kind are now known to be far from
uncommon, although they cannot always, or often, be so clearly and
distinctly traced as in the illustration which we have selected.

[Illustration: FIG. 106.--D. _Nectria_ surrounding _Tubercularia_; E.
tuft of _Nectria cinnabarina_; F. section of stroma; G. ascus and
paraphyses.]

It is not uncommon for the conidia of the _Sphæria_ to partake of the
characteristics of a mould, and then the perithecia are developed
amongst the conidial threads. A recently recorded instance of this
relates to _Sphæria Epochnii_, B. and Br.,[L] the conidia form of
which was long known before the _Sphæria_ related to it was
discovered, under the name of _Epochnium fungorum_. The _Epochnium_
forms a thin stratum, which overruns various species of _Corticium_.
The conidia are at first uniseptate. The perithecia of the _Sphæria_
are at first pale bottle-green, crowded in the centre of the
_Epochnium_, then black green granulated, sometimes depressed at the
summit, with a minute pore. The sporidia are strongly constricted in
the centre, at first uniseptate, with two nuclei in each division.

Another _Sphæria_ in which the association is undoubted is the
_Sphæria aquila_, Fr.,[M] which is almost always found nestling in a
woolly brown subiculum, for the most part composed of barren brown
jointed threads. These threads, however, produce, under favourable
conditions, mostly before the perfection of the perithecia, minute
subglobose conidia, and in this state constitute what formerly bore
the name of _Sporotrichum fuscum_, Link., but now recognized as the
conidia of _Sphæria aquila_.

In _Sphæria nidulans_, Schw., a North American species, we have more
than once found the dark brown subiculum bearing large triseptate
conidia, having all the characters of the genus _Helminthosporium_. In
_Sphæria pilosa_, P., Messrs. Berkeley and Broome have observed oblong
conidia, rather irregular in outline, terminating the hairs of the
perithecium.[N] The same authors have also figured the curious
pentagonal conidia springing from flexuous threads accompanying
_Sphæria felina_, Fckl.,[O] and also the threads resembling those of a
_Cladotrichum_ with the angular conidia of _Sphæria cupulifera_, B.
and Br.[P] A most remarkable example is also given by the Brothers
Tulasne in _Pleospora polytricha_, in which the conidia-bearing
threads not only surround, but grow upon the perithecia, and are
crowned by fascicles of septate conidia.[Q]

Instances of this kind have now become so numerous that only a few can
be cited as examples of the rest. It is not at all improbable that the
majority of what are now classed together as species under the genus
of black moulds, _Helminthosporium_, will at some not very distant
period be traced as the conidia of different species of ascomycetous
fungi. The same fate may also await other allied genera, but until
this association is established, they must keep the rank and position
which has been assigned to them.

Another form of dualism, differing somewhat in character from the
foregoing, finds illustration in the sphæriaceous genus _Melanconis_,
of Tulasne, in which the free spores are still called conidia, though
in most instances produced in a sort of spurious conceptaculum, or
borne on short threads from a kind of cushion-shaped stroma. In the
_Melanconis stilbostoma_,[R] there are three forms, one of slender
minute bodies, oozing out in the form of yellow tendrils, which may be
spermatia, formerly called _Nemaspora crocea_. Then there are the oval
brown or olive brown conidia, which are at first covered, then oozing
out in a black pasty mass, formerly _Melanconium bicolor_, and finally
the sporidia in asci of _Sphæria stilbostoma_, Fries. In _Melanconis
Berkeleii_, Tul., the conidia are quadrilocular, previously known as
_Stilbospora macrosperma_, B. and Br. In a closely-allied species from
North America, _Melanconis bicornis_, Cooke, the appendiculate
sporidia are similar, and the conidia would also appear to partake of
the character of _Stilbospora_. We may remark here that we have seen a
brown mould, probably an undescribed species of _Dematiei_, growing in
definite patches around the openings in birch bark caused by the
crumpent ostiola of the perithecia of _Melanconis stilbostoma_, from
the United States.

In _Melanconis lanciformis_,[S] Tul., there are, it would appear,
four forms of fruit. One of these consists of conidia, characterized
by Corda as _Coryneum disciforme_.[T] Stylospores, which are also
figured by Corda under the name of _Coniothecium betulinum_;
pycnidia,[U] first discovered by Berkeley and Broome, and named by
them _Hendersonia polycystis_;[V] and the ascophorous fruits which
constituted the _Sphæria lanciformis_ of Fries. Mr. Currey indicated
_Hendersonia polycystis_, B. and Br., as a form of fruit of this
species in a communication to the Royal Society in 1857.[W] He says
this plant grows upon birch, and is in perfection in very moist
weather, when it may be recognized by the large black soft
gelatinous protuberances on the bark, formed by spores escaping and
depositing themselves upon and about the apex of the perithecium.
This I suspect to be an abnormal state of a well-known Sphæria (_S.
lanciformis_), which grows upon birch, and upon birch only.

We might multiply, almost indefinitely, instances amongst the
_Sphæriacei_, but have already given sufficient for illustration, and
will therefore proceed briefly to notice some instances amongst the
_Discomycetes_, which also bear their complete or perfect fruit in
asci.

The beautiful purple stipitate cups of _Bulgaria sarcoides_, which may
be seen flourishing in the autumn on old rotten wood, are often
accompanied by club-shaped bodies of the same colour; or earlier in
the season these clavate bodies may be found alone, and at one time
bore the name of _Tremella sarcoides_. The upper part of these clubs
disseminate a great abundance of straight and very slender spermatia.
Earlier than this they are covered with globose conidia. The
fully-matured _Bulgaria_ develops on its hymenium clavate delicate
asci, each enclosing eight elongated hyaline sporidia, so that we have
three forms of fruit belonging to the same fungus, viz. conidia and
spermatia in the _Tremella_ stage, and sporidia contained in asci in
the mature condition.[X] The same phenomena occur with _Bulgaria
purpurea_, a larger species with different fruit, long confounded with
_Bulgaria sarcoides_.

On the dead stems of nettles it is very common to meet with small
orange tubercles, not much larger than a pin's head, which yield at
this stage a profusion of slender linear bodies, produced on delicate
branched threads, and at one time bore the name of _Dacrymyces
Urticæ_, but which are now acknowledged to be only a condition of a
little tremelloid _Peziza_ of the same size and colour, which might be
mistaken for it, if not examined with the microscope, but in which
there are distinct asci and sporidia. Both forms together are now
regarded as the same fungus, under the name of _Peziza fusarioides_,
B.

The other series of phenomena grouped together under the name of
polymorphism relate to forms which are removed from each other, so
that the mycelium is not identical, or, more usually, produced on
different plants. The first instance of this kind to which we shall
make reference is one of particular interest, as illustrative of the
old popular creed, that berberry bushes near corn-fields produced
mildewed corn. There is a village in Norfolk, not far from Great
Yarmouth, called "Mildew Rollesby," because of its unenviable
notoriety in days past for mildewed corn, produced, it was said, by
the berberry bushes, which were cut down, and then mildew disappeared
from the corn-fields, so that Rollesby no longer merited its
_sobriquet_. It has already been shown that the corn-mildew (_Puccinia
graminis_) is dimorphous, having a one-celled fruit (_Trichobasis_),
as well as a two-celled fruit (_Puccinia_). The fungus which attacks
the berberry is a species of cluster-cup (_Æcidium berberidis_), in
which little cup-like peridia, containing bright orange pseudospores,
are produced in tufts or clusters on the green leaves, together with
their spermogonia.

De Bary's observations on this association of forms were published in
1865.[Y] In view of the popular belief, he determined to sow the
spores of _Puccinia graminis_ on the leaves of the berberry. For this
purpose he selected the septate resting spores from _Poa pratensis_
and _Triticum repens_. Having caused the spores to germinate in a
moist atmosphere, he placed fragments of the leaves on which they had
developed their secondary spores on young but full-grown berberry
leaves, under the same atmospheric conditions. In from twenty-four to
forty-eight hours a quantity of the germinating threads had bored
through the walls and penetrated amongst the subjacent cells. This
took place both on the upper and under surface of the leaves. Since,
in former experiments, it appeared that the spores would penetrate
only in those cases where the plant was adapted to develop the
parasite, the connection between _P. graminis_ and _Æcid. berberidis_
seemed more than ever probable. In about ten days the spermogonia
appeared. After a time the cut leaves began to decay, so that the
fungus never got beyond the spermogonoid stage. Some three-year-old
seedlings were then taken, and the germinating resting spores applied
as before. The plants were kept under a bell-glass from twenty-four to
forty-eight hours, and then exposed to the air like other plants. From
the sixth to the tenth day, yellow spots appeared, with single
spermogonia; from the ninth to the twelfth, spermogonia appeared in
numbers on either surface; and, a few days later, on the under surface
of the leaves, the cylindrical sporangia of the _Æcidium_ made their
appearance, exactly as in the normally developed parasite, except that
they were longer, from being protected from external agents. The
younger the leaves, the more rapid was the development of the
parasite, and sometimes, in the younger leaves, the luxuriance was far
greater than in free nature. Similar plants, to the number of two
hundred, were observed in the nursery, and though some of them had
_Æcidium_ pustules, not one fresh pustule was produced; while two
placed under similar circumstances, but without the application of any
resting spores, remained all the summer free from _Æcidium_. It seems,
then, indubitable so far that _Æcidium berberidis_ does spring from
the spores of _Puccinia graminis_.

It has, however, to be remarked that De Bary was not equally
successful in producing the _Puccinia_ from the spores of the
_Æcidium_. In many cases the spores do not germinate when placed on
glass, and they do not preserve their power of germinating very long.
He reverts then to the evidence of experiments instituted by
agriculturists. Bönninghausen remarked, in 1818, that wheat, rye, and
barley which were sown in the neighbourhood of a berberry bush covered
with _Æcidium_ contracted rust immediately after the maturation of the
spores of the _Æcidia_. The rust was most abundant where the wind
carried the spores. The following year the same observations were
repeated; the spores of the _Æcidium_ were collected, and applied to
some healthy plants of rye. After five or six days these plants were
affected with rust, while the remainder of the crop was sound. In
1863 some winter rye was sown round a berberry bush, which in the
following year was infested with _Æcidium_, which was mature in the
middle of May, when the rye was completely covered with rust. Of the
wild grasses near the bush, _Triticum repens_ was most affected. The
distant plants of rye were free from rust.

[Illustration: FIG. 107.--Cells and pseudospores of _Æcidium berberidis_.]

The spores of the _Æcidium_ would not germinate on berberry leaves;
the berberry _Æcidium_ could not therefore spring from the previous
_Æcidium_. The uredospores of _Puccinia graminis_ on germinating
penetrate into the parenchym of the grass on which they are sown; but
on berberry leaves, if the tips of the threads enter for a short
distance into the stomates their growth at once ceases, and the leaves
remain free from parasites.

[Illustration: FIG. 108.--Cells and pseudospores of _Æcidium graveolens_.]

Montagne has, however, described a _Puccinia berberidis_ on leaves of
_Berberis glauca_ from Chili, which grows in company with _Æcidium
berberidis_. This at first sight seems to contradict the above
conclusions; but the _Æcidium_ which from the same disc produces the
puccinoid resting spores, appears to be different from the European
species, inasmuch as the cells of the wall of the sporangium are twice
as large, and the spores decidedly of greater diameter.[Z] The resting
spores, moreover, differ not only from those of _Puccinia graminis_,
but from those of all other European species.

From this account, then, it is extremely probable that the _Æcidium_
of the berberry enters into the cycle of existence of _Puccinia
graminis_, and, if this be true, wherefore should not other species
of _Puccinia_ be related in like manner to other _Æcidia_? This is the
conclusion to which many have arrived, and, taking advantage of
certain presumptions, have, we fear, rashly associated many such
forms together without substantial evidence. On the leaves of the
primrose we have commonly a species of _Æcidium_, _Puccinia_, and
_Uromyces_ nearly at the same time; we may imagine that all these
belong to one cycle, but it has not yet been proved. Again, _Uromyces
cacaliæ_, Unger, _Uredo cacaliæ_, Unger, and _Æcidium cacaliæ_,
Thumen, are considered by Heufler[a] to form one cycle. Numerous
others are given by Fuckel,[b] and De Bary, in the same memoir from
which we have already cited, notes _Uromyces appendiculatus_, Link.,
_U. phaseolorum_, Tul., and _Puccinia tragopogonis_, Ca., as
possessing five kinds of reproductive organs. Towards the end of the
year, shortly stipitate spores appear on their stroma, which do not
fall off. These spores, which do not germinate till after a shorter
or longer winter rest, may conveniently be called resting spores, or,
as De Bary calls them, _teleutospores_, being the last which are
produced. These at length germinate, become articulated, and produce
ovate or kidney-shaped spores, which in their turn germinate,
penetrating the cuticle of the mother plant, avoiding the stomates or
apertures by which it breathes. After about two or three weeks,
the mycelium, which has ramified among the tissues, produces an
_Æcidium_, with its constant companion, spermogonia--distinct cysts,
that is, from which a quantity of minute bodies ooze out, often in
the form of a tendril, the function of which is imperfectly known at
present, but which from analogy we regard as a form of fruit,
though it is just possible that they may be rather of the nature of
spermatozoids. The _Æcidia_ contain, within a cellular membranous
sac, a fructifying disc, which produces necklaces of spores, which
ultimately separate from each other in the form of a granular powder.
The grains of which it is composed germinate in their turn, no
longer avoiding the stomates as before, but penetrating through
their aperture into the parenchym. The new resultant mycelium
reproduces the _Uredo_, or fifth form of fructification, and the
_Uredo_ spores fall off like those of the _Æcidium_, and in respect of
germination, and mode of penetration, present precisely the same
phenomena. The disc which has produced the _Uredo_ spores now gives
rise to the resting spores, and so the cycle is complete.[c]

The late Professor Oersted, of Copenhagen, was of opinion that he had
demonstrated the polymorphy of the Tremelloid Uredines, and satisfied
himself that the one condition known as _Podisoma_ was but another
stage of _Roestelia_.[d] Some freshly gathered specimens of
_Gymnosporangium_ were damped with water, and during the night
following the spores germinated profusely, so that the teleutospores
formed an orange-coloured powder. A little of this powder was
placed on the leaves of five small sorbs, which were damped and
placed under bell-glasses. In five days yellow spots were seen on
the leaves, and in two days more indications of spermogonia. The
spermatia were discharged, and in two months from the first
sowing, the peridia of _Roestelia_ appeared, and were developed.
"This trial of spores," says Oersted, "has conduced to the result
expected, and proves that the teleutospores of _Gymnosporangium_,
when transported upon the sorb, give rise to a totally different
fungus, the _Roestelia cornuta_, that is to say, that an alternate
generation comes between these fungi. They appertain in consequence
to a single species, and the _Gymnosporangium_ ceased to be an
independent species, and must be considered as synonymous with the
first generation of _Roestelia_. The spores have been transported
upon young shoots of the juniper-tree, and have now commenced to
produce some mycelium in the bark. There is no doubt that in next
spring it will result in _Gymnosporangium_."

Subsequently the same learned professor instituted similar experiments
upon other hosts, with the spores of _Podisoma_, and from thence he
concluded that _Roestelia_ and _Podisoma_, in all their known species,
were but forms the one of the other. Hitherto we are not aware that
these results have been confirmed, or that the sowing of the spores of
_Roestelia_ on juniper resulted in _Podisoma_. Such experiments should
be received always with care, and not too hastily accepted in their
apparent results as proven facts. Who shall say that _Roestelia_ would
not have appeared on _Sorbus_ within two months without the sowing of
_Podisoma_ spores?--because it is not by any means uncommon for that
fungus to appear upon that plant. It is true many mycologists write
and speak of _Roestelia_ and _Podisoma_ (or _Gymnosporangium_) as
identical; but, as we think, without the evidence being so complete as
to be beyond suspicion. It is, nevertheless, a curious fact that in
Europe the number of species of _Roestelia_ and _Podisoma_ are equal,
if one species be excluded, which is certainly not a good _Podisoma_,
for the reception of which a new genus has been proposed.[e]

Amongst the ascigerous fungi will be found a curious but interesting
genus formerly called _Cordyceps_, but for which Tulasne, in
consequence of the discovery of secondary forms of fruit, has
substituted that of _Torrubia_.[f] These curious fungi partake more
or less of a clavate form, and are parasitic on insects. The pupæ
of moths are sometimes seen bearing upon them the white branched
mould, something like a _Clavaria_ in appearance, to which the name of
_Isaria farinosa_ has been given. According to Tulasne, this is the
conidia form of the bright scarlet, club-shaped body which is also
found on dead pupæ, called _Torrubia militaris_. An American mould of
the same genus, _Isaria sphingum_, found on mature moths,[g] is in
like manner declared to be the conidia of _Torrubia sphingum_;
whereas a similar mould, found on dead spiders, called _Isaria
arachnophila_,[h] is probably of a similar nature. An allied kind
of compact mould, which is parasitic on _Cocci_, on the bark of
trees, recently found in England by Mr. C. E. Broome, and named
_Microcera coccophila_,[i] is said by Tulasne to be a condition of
_Sphærostilbe_, and it is intimated that other productions of a
similar character bear like relations to other sphæriaceous fungi.
For many species of _Torrubia_ no corresponding conidia are yet
known.

Some instances might be noted, not without interest, in which the
facts of dimorphism or polymorphism have not been satisfactorily
proved, but final judgment is held in suspense until suspicion is
replaced by conviction. Some years since, a quantity of dead box
leaves were collected, on which flourished at the time a mould named
_Penicillium roseum_. This mould has a roseate tint, and occurs in
patches on the dead leaves lying upon the ground; the threads are
erect and branched above, bearing chains of oblong, somewhat
spindle-shaped spores, or, perhaps more accurately, conidia. When
collected, these leaves were examined, and nothing was observed or
noted upon them except this _Penicillium_. After some time, certainly
between two and three years, during which period the box remained
undisturbed, circumstances led to the examination again of one or two
of the leaves, and afterwards of the greater number of them, when the
patches of _Penicillium_ were found to be intermixed with another
mould of a higher development, and far different character. This
mould, or rather _Mucor_, consists of erect branching threads, many of
the branches terminating in a delicate globose, glassy head, or
sporangium, containing numerous very minute subglobose sporidia. This
species was named _Mucor hyalinus_.[j] The habit is very much like
that of the _Penicillium_, but without any roseate tint. It is almost
certain that the _Mucor_ could not have been present when the
_Penicillium_ was examined, and the leaves on which it had grown were
enclosed in the tin box, but that the _Mucor_ afterwards appeared on
the same leaves, sometimes from the same patches, and, as it would
appear, from the same mycelium. The great difference in the two
species lies in the fructification. In the _Penicillium_, the spores
are naked, and in moniliform threads; whilst in _Mucor_ the spores are
enclosed within globose membraneous heads or sporangia. Scarcely can
we doubt that the _Mucor_ alluded to above, found thus intermixed,
under peculiar circumstances, with _Penicillium roseum_, is no other
than the higher and more complete form of that species, and that the
_Penicillium_ is only its conidiiferous state. The presumption in this
case is strong, and not so open to suspicion as it would be did not
analogy render it so extremely probable that such is the case, apart
from the fact of both forms springing from the same mass of mycelium.
In such minute and delicate structures it is very difficult to
manipulate the specimens so as to arrive at positive evidence. If a
filament of mycelium could be isolated successfully, and a fertile
thread, bearing the fruit of each form, could be traced from the same
individual mycelium thread, the evidence would be conclusive. In
default of such conclusive evidence, we are compelled to rest with
assumption until further researches enable us to record the assumption
as fact.[k]

Apropos of this very connection of _Penicillium_ with _Mucor_, a
similar suspicion attaches to an instance noted by a wholly
disinterested observer to this effect. "On a preparation preserved in
a moist chamber, on the third day a white speck was seen on the
surface, consisting of innumerable 'yeast' cells, with some filaments,
branching in all directions. On the fourth day tufts of _Penicillium_,
had developed two varieties--_P. glaucum_ and _P. viride_. This
continued until the ninth day, when a few of the filaments springing
up in the midst of the _Penicillium_ were tipped with a dewdrop-like
dilatation, excessively delicate--a mere distended pellicle. In some
cases they seemed to be derived from the same filament as others
bearing the ordinary branching spores of _Penicillium_, but of this I
could not be positive. This kind of fructification increased rapidly,
and on the fourteenth day spores had undoubtedly developed within the
pellicle, just as had been observed in a previous cultivation,
precisely similar revolving movements being also manifested."[l]
Although we have here another instance of _Mucor_ and _Penicillium_
growing in contact, the evidence is insufficient to warrant more than
a suspicion of their identity, inasmuch as the equally minute spores
of _Mucor_ and _Penicillium_ might have mingled, and each producing
its kind, no relationship whatever have existed between them, except
their development from the same matrix.

Another case of association--for the evidence does not proceed
further--was recorded by us, in which a dark-coloured species of
_Penicillium_ was closely associated with what we now believe to be a
species of _Macrosporium_--but then designated a _Sporidesmium_--and a
minute _Sphæria_ growing in succession on damp wall-paper. Association
is all that the _facts_ warrant us in calling it.

We cannot forbear alluding to one of the species of _Sphæria_ to which
Tulasne[m] attributes a variety of forms of fruit, and we do so here
because we think that a circumstance so extraordinary should be
confirmed before it is accepted as absolutely true. This refers to the
common _Sphæria_ found on herbaceous plants, known as _Sphæria_
(_Pleospora_) _herbarum_. First of all the very common mould called
_Cladosporium herbarum_ is constituted as conidia, and of this again
_Macrosporium sarcinula_, Berk., is considered to be another
condition. In the next place, _Cytispora orbicularis_, Berk., and
_Phoma herbarum_, West., are regarded as pycnidia, enclosing
stylospores. Then _Alternaria tenuis_, Pr.,[n] which is said to be
parasitic on _Cladosporium herbarum_, is held to be only a form of
that species, so that here we have (including the _perithecia_) no
less than six forms or phases for the same fungus. As _Macrosporium
Cheiranthi_, Pr., often is found in company with _Cladosporium
herbarum_, that is also open to suspicion.

We have adduced in the foregoing pages a few instances which will
serve to illustrate the polymorphism of fungi. Some of these it will
be observed are accepted as beyond doubt, occurring as they do in
intimate relationship with each other. Others are considered as
scarcely so well established, but probable, although developed
sometimes on different species of plants. Finally, some are regarded
as hitherto not satisfactorily proved, or, it may be, only suspicious.
In this latter group, however much probability may be in their favour,
it can hardly be deemed philosophical to accept them on such slender
evidence as in some cases alone is afforded. It would not have been
difficult to have extended the latter group considerably by the
addition of instances enumerated by various mycologists in their works
without any explanation of the data upon which their conclusions have
been founded. In fact, altogether this chapter must be accepted as
illustrative and suggestive, but by no means as exhaustive.

   [A] De Bary, in "Quarterly German Magazine" (1872), p. 197.

   [B] The method pursued by Messrs. Berkeley and Hoffmann of
       surrounding the drop of fluid, in which a definite number of
       spores or yeast globules had been placed, with a pellicle of
       air, into which the germinating threads might pass and
       fructify, is perhaps the most satisfactory that has been
       adopted, though it requires nice manipulation. If carefully
       managed, the result is irrefragable, though doubts have been
       cast, without any reason, on their observations.

   [C] De Bary, "Uber die Brandpilze" (Berlin, 1853), pl. iv. figs. 3,
       4, 5.

   [D] A. de Bary, on Mildew and Fermentation, in "Quarterly German
       Magazine," vol. ii. 1872.

   [E] Berkeley, "Introd. Crypt. Bot." p. 78, fig. 20.

   [F] See also Berkeley, in "Trans. Hort. Soc. London," vol. ix. p.
       68.

   [G] Berkeley, in "Ann. Nat. Hist." (June, 1838), No. 116.

   [H] "Grevillea," vol. i. p. 176.

   [I] Tulasne, "On Certain Fungicolous Sphæriæ," in "Ann. des Sci.
       Nat." 4^me sér. xiii. (1860), p. 5.

   [J] "A Currant Twig, and Something on it," in "Gardener's Chronicle,"
       January 28, 1871.

   [K] Figs. 104 to 106 by permission from the "Gardener's Chronicle."

   [L] Berkeley and Broome, in "Annals of Natural History" (1866), No.
       1177, pl. v. fig. 36; Cooke, "Handbook," ii. p. 866.

   [M] Cooke, "Handbook," ii. p. 853, No. 2549; specimens in Cooke's
       "Fungi Britannici Exsiccati," No. 270.

   [N] Berk. and Br. "Ann. Nat. Hist." (1865), No. 1096.

   [O] "Ann. Nat. Hist." (1871), No. 1332, pl. xx. fig. 23.

   [P] Ibid. No. 1333, pl. xxi. fig. 24.

   [Q] Tulasne, "Selecta Fungorum Carpologia," ii. p. 269, pl. 29.

   [R] Cooke, "Handbook," ii. p. 878; Tulasne, "Carpologia," ii. p. 120,
       plate 14.

   [S] Tulasne, "Selecta Fung. Carp.," ii. plate 16.

   [T] Corda, "Icones Fungorum," vol. iii. fig. 91.

   [U] Corda, "Icones," vol. i. fig. 25.

   [V] Berk. and Br. "Ann. Nat. Hist." No. 415.

   [W] Currey, in "Philosoph. Trans. Roy. Soc." (1857), pl. 25.

   [X] Tulasne, "On the Reproductive Apparatus of Fungi," in "Comptes
       Rendus" (1852), p. 841; and Tulasne, "Selecta Fungorum
       Carpologia," vol. iii.

   [Y] "Monatsbericht der Koniglichen Preuss, Acad. der Wissenschaften
       au Berlin," Jan. 1865; Summary, in "Journ. Roy. Hort. Soc.,
       London," vol. i. n.s. p. 107.

   [Z] We have before us an _Æcidium_ on leaves of _Berberis vulgaris_,
       collected at Berne by Shuttleworth in 1833. It is named by him
       _Æcidium graveolens_, and differs in the following particulars
       from _Æcidium berberidis_. The peridia are scattered as in _Æ.
       Epilobii_, and not collected in clusters. They are not so much
       elongated. The cells are larger, and the orange spores nearly
       twice the diameter. There is a decided, strong, but unpleasant
       odour in the fresh plant; hence the name. The above figures
       (figs. 107, 108) of the cells and spores of both species are
       drawn by camera lucida to the same scale--380 diameters.

   [a] Freiherrn von Hohenbühel-Heufler, in "Oesterr. Botan.
       Zeitschrift," No. 3, 1870.

   [b] Fuckel, "Symbolæ Mycologicæ" (1869), p. 49.

   [c] Almost simultaneously with De Bary, the late Professor Oersted
       instituted experiments, from which the same results ensued, as
       to _Æcidium berberidis_ and _Puccinia graminis_. See "Journ.
       Hort. Soc. Lond." new ser. i., p. 85.

   [d] "Oversigt over det Kon. Danske Videns. Selskabs" (1866), p. 185,
       t. 3, 4; (1867,) p. 208, t. 3, 4; "Résumé du Bulletin de la
       Soc. Roy. Danoise des Sciences" (1866), p. 15; (1867), p. 38;
       "Botanische Zeitung" (1867), p. 104; "Quekett Microscopical
       Club Journal," vol. ii. p. 260.

   [e] This is _Podisoma foliicola_, B. and Br., or, as proposed in
       "Journ. Quekett Club," ii. p. 267, _Sarcostroma Berkeleyi_, C.

   [f] Tulasne, "Selecta Fungorum Carpologia," iii. p. 6, pl. i. figs.
       19-31.

   [g] Cramer's "Papilio Exotic" (1782), fig. 267.

   [h] Cooke, "Handbook," p. 548, No. 1639.

   [i] Ibid. p. 556, No. 1666.

   [j] Specimens were published under this name in Cooke's "Fungi
       Britannici Exsiccati," No. 359.

   [k] Cooke, "On Polymorphism in Fungi," in "Popular Science Review."

   [l] Lewis's "Report on Microscopic Objects found in Cholera
       Evacuations," Calcutta, 1870.

   [m] Tulasne, "Selecta Fungorum Carpologia," ii. p. 261.

   [n] Corda, "Prachtflora," plate vii.



X.

INFLUENCES AND EFFECTS.


It is no longer doubted that fungi exercise a large and very important
influence in the economy of nature. It may be that in some directions
these influences are exaggerated; but it is certain that on the whole
their influence is far more important for evil and for good than that
of any other of the Cryptogamia. In our endeavour to estimate the
character and extent of these influences it will prove advantageous to
examine them under three sections. 1. Their influence on man. 2. Their
influence on lower animals. 3. Their influence on vegetation. Under
these sections the chief facts may be grouped, and some approximate
idea obtained of the very great importance of this family of inferior
plants, and consequently the advisability of pursuing their study more
thoroughly and nationally than has hitherto been done.

I. In estimating the influence of fungi upon man, we naturally enough
seek in the first instance to know what baneful effects they are
capable of producing on food. Although in the case of "poisonous
fungi," popularly understood, fungi may be the passive agents, yet
they cannot be ignored in an inquiry of this nature. Writing of the
Uses of Fungi, we have already shown that a large number are available
for food, and some of these real delicacies; so, on the other hand, it
becomes imperative, even with stronger emphasis, to declare that many
are poisonous, and some of them virulently so. It is not sufficient to
say that they are perfectly harmless until voluntarily introduced into
the human system, whilst it is well known that accidents are always
possible, and probably would be if every baneful fungus had the word
POISON inscribed in capitals on its pileus.

The inquiry is constantly being made as to what plain rules can be
given for distinguishing poisonous from edible fungi, and we can
answer only that there are none other than those which apply to
flowering plants. How can aconite, henbane, oenanthe, stramonium,
and such plants, be distinguished from parsley, sorrel, watercress,
or spinach? Manifestly not by any general characters, but by
specific differences. And so it is with the fungi. We must learn to
discriminate _Agaricus muscarius_ from _Agaricus rubescens_, in the
same manner as we would discriminate parsley from _Æthusa cynapium_.
Indeed, fungi have an advantage in this respect, since one or two
general cautions can be given, when none such are applicable for
higher plants. For instance, it may be said truly that all fungi
that exhibit a rapid change to blue when bruised or broken should
be avoided; that all Agarics are open to suspicion which possess an
acrid taste; that fungi found growing on wood should not be eaten
unless the species is well known; that no species of edible fungus
has a strong, unpleasant odour, and similar cautions, which, after
all, are insufficient. The only safe guide lies in mastering, one by
one, the specific distinctions, and increasing the number of one's
own esculents gradually, by dint of knowledge and experience, even as
a child learns to distinguish a filbert from an acorn, or with
wider experience will thrust in his mouth a leaf of _Oxalis_ and
reject that of the white clover.

One of the most deleterious of fungi that we possess is at the same
time one of the most beautiful. This is the _Agaricus muscarius_, or
Fly Agaric, which is sometimes used as a fly poison.[A] It has a
bright crimson pileus studded with pale whitish (sometimes yellowish)
warts, and a stem and gills of ivory whiteness. Many instances have
been recorded of poisoning by this fungus, and amongst them some
British soldiers abroad, and yet it cannot be doubted that this fungus
is eaten in Russia. Two instances have come under our notice of
persons with some botanical knowledge, and one a gardener, who had
resided in Russia and eaten of this fungus. In one case the Fly Agaric
was collected and shown to us, and in the other the figure was
indicated, so that we might be under no doubt as to the species. Only
one hypothesis can be advanced in explanation. It is known that a
large number of fungi are eaten in Russia, and that they enter much
into the domestic cookery of the peasantry, but it is also known that
they pay considerable attention to the mode of cooking, and add a
large amount of salt and vinegar, both of which, with long boiling,
must be powerful agents in counteracting the poison (probably somewhat
volatile) of such fungi as the Fly Agaric. In this place we may give a
recipe published by a French author of a process for rendering
poisonous fungi edible. It must be taken on his authority, and not our
own, as we have never made the experiment, notwithstanding it seems
somewhat feasible:--For each pound of mushrooms, cut into moderately
small pieces, take a quart of water acidulated with two or three
spoonfuls of vinegar, or two spoonfuls of bay salt. Leave the
mushrooms to macerate in the liquid for two hours, then wash them with
plenty of water; this done, put them in cold water and make them boil.
After a quarter or half hour's boiling take them off and wash them,
then drain, and prepare them either as a special dish, or use them for
seasoning in the same manner as other species.[B]

This method is said to have been tried successfully with some of the
most dangerous kinds. Of these may be mentioned the emetic mushroom,
_Russula emetica_, with a bright red pileus and white gills, which
has a clear, waxy, tempting appearance, but which is so virulent that
a small portion is sufficient to produce disagreeable consequences. It
would be safer to eschew all fungi with a red or crimson pileus than
to run the risk of indulging in this. A white species, which, however,
is not very common, with a bulbous base enclosed in a volva, called
_Agaricus vernus_, should also be avoided. The pink spored species
should also be regarded with suspicion. Of the _Boleti_ several turn
blue when cut or broken, and these again require to be discarded. This
is especially the case with _Boletus luridus_[C] and _Boletus
Satanas_,[D] two species which have the under surface or orifice of
the pores of a vermilion or blood-red colour.

Not only are species which are known to be poisonous to be avoided,
but discretion should be used in eating recognized good species. Fungi
undergo chemical changes so rapidly that even the cultivated mushroom
may cause inconvenience if kept so long after being gathered as to
undergo chemical change. It is not enough that they should be of a
good kind, but also fresh. The employment of plenty of salt in their
preparation is calculated very much to neutralize any deleterious
property. Salt, pepper, and vinegar are much more freely employed
abroad in preparing fungi than with us, and with manifest advantage.

It is undoubtedly true that fungi exert an important influence in
skin diseases. This seems to be admitted on all hands by medical
men,[E] however much they may differ on the question of the extent to
which they are the cause or consequence of disease. Facts generally
seem to bear out the opinion that a great number of skin diseases
are aggravated, and even produced, by fungi. Robin[F] insists that a
peculiar soil is necessary, and Dr. Fox says it is usually taught
that tuberculous, scrofulous, and dirty people furnish the best
nidus. It is scarcely necessary to enumerate all these diseases,
with which medical men are familiar, but simply to indicate a few.
There is favus or scall-head, called also "porrigo," which has its
primary seat in the hair follicles. Plica polonica, which is
endemic in Russia, is almost cosmopolitan. Then there is Tinea
tonsurans, Alopecia, Sycosis, &c., and in India a more deeply-seated
disease, the Madura Foot, has been traced to the ravages of a fungus
described under the name of _Chionyphe Carteri_.[G] It is probable
that the application of different names to the very often imperfect
forms of fungi which are associated with different diseases is not
scientifically tenable. Perhaps one or two common moulds, such as
_Aspergillus_ or _Penicillium_, lie at the base of the majority, but
this is of little importance here, and does not affect the general
principle that some skin diseases are due to fungi.

Whilst admitting that there are such diseases, it must be understood
that diseases have been attributed to fungi as a primary cause, when
the evidence does not warrant such a conclusion. Diphtheria and thrush
have been referred to the devastations of fungi, whereas diphtheria
certainly may and does occur without any trace of fungi. Fevers may
sometimes be accompanied by fungoid bodies in the evacuations, but it
is very difficult to determine them. The whole question of epidemic
diseases being caused by the presence of fungi seems based on most
incomplete evidence. Dr. Salisbury was of opinion that camp measles
was produced by _Puccinia graminis_, the pseudospores of which
germinated in the damp straw, disseminated the resultant secondary
bodies in the air, and caused the disease. This has never been
verified. Measles, too, has been attributed freely, as well as
scarlatina,[H] to fungal influences, and the endeavours to implicate
fungi in being the cause of cholera have been pertinaciously
persevered in with no conviction. The presence of certain cysts, said
to be those of _Urocystis_, derived from rice, was announced by Dr.
Hallier, but when it was shown that no such fungus was found on rice,
this phase of the theory collapsed. Special and competent experts were
sent from this country to examine the preparations and hear the
explanations of Dr. Hallier on his theory of cholera contagion, but
they were neither convinced nor satisfied.

As long ago as 1853, Dr. Lauder Lindsay examined and reported on
cholera evacuations, and in 1856 he declared--"It will be evident that
I can see no satisfactory groundwork for the fungus theory of cholera,
which I am not a little surprised to find still possesses powerful
advocates."[I] And of the examinations undertaken by him he
writes:--"The mycelium and sporules of various species of fungi,
constituting various forms of vegetable mould, were found in the scum
of the vomit, as well as of the stools, but only at some stage of
decomposition. They are found, however, under similar circumstances,
in the vomit and stools of other diseases, and, indeed, in all
decomposing animal fluids, and they are therefore far from peculiar to
cholera."

Some writers have held that the atmosphere is often highly charged
with fungi spores, others have denied the presence of organic bodies
to any extent in the air. The experiments conducted in India by Dr.
Cunningham[J] have been convincing enough on this point. This report
states that spores and similar cells were of constant occurrence, and
were generally present in considerable numbers. That the majority of
the cells were living and ready to undergo development on meeting with
suitable conditions was very manifest, as in those cases in which
preparations were retained under observation for any length of time,
germination rapidly took place in many of the cells; indeed, many
spores already germinating were deposited on the slides. In few
instances did any development take place beyond the formation of
mycelium or masses of toruloid cells, but in one or two distinct
sporules were developed on the filaments arising from some of the
larger septate spores, and in a few others _Penicillium_ and
_Aspergillus_ produced their characteristic heads of fructification.

With regard to the precise nature of the spores and other cells
present in various instances little can be said, as, unless their
development were to be carefully followed out through all its stages,
it is impossible to refer them to their correct species or even
genera. The greater number of them are apparently referable to the old
orders of fungi--_Sphæronemei_, _Melanconei_, _Torulacei_, _Dematiei_,
and _Mucedines_, while some probably belonged to the _Pucciniei_ and
_Coæmacei_. Amongst those belonging to the _Torulacei_, the most
interesting was a representative of the rare genus _Tetraploa_.
Distinct green algoid cells occurred in some specimens. Then follow in
the report details of observations made on the rise and fall of
diseases, of which diarrhoea, dysentery, cholera, ague, and dengue
were selected and compared with the increase or diminution of
atmospheric cells. The conclusions arrived at are:--

"Spores and other vegetable cells are constantly present in
atmospheric dust, and usually occur in considerable numbers; the
majority of them are living, and capable of growth and development.
The amount of them present in the air appears to be independent of
conditions of velocity and direction of the wind, and their number is
not diminished by moisture.

"No connection can be traced between the numbers of bacteria, spores,
&c., present in the air, and the occurrence of diarrhoea, dysentery,
cholera, ague, or dengue, nor between the presence or abundance of any
special form or forms of cells, and the prevalence of any of these
diseases.

"The amount of inorganic and amorphous particles and other débris
suspended in the atmosphere is directly dependent on conditions of
moisture and velocity of wind."

This report is accompanied by fourteen large and well-executed plates,
each containing hundreds of figures of organic bodies collected from
the air between February and September. It is valuable both for its
evidence as to the number and character of the spores in the air, and
also for the tables showing the relation between five forms of
disease, and their fluctuations, as compared with the amount of spores
floating in the atmosphere.

We are fain to believe that we have represented the influence of fungi
on man as far as evidence seems to warrant. The presence of forms of
mould in some of their incipient conditions in different diseased
parts of the human body, externally and internally, may be admitted
without the assumption that they are in any manner the cause of the
diseased tissues, except in such cases as we have indicated. Hospital
gangrene may be alluded to in this connection, and it is possible that
it may be due to some fungus allied to the crimson spots (blood rain)
which occur on decayed vegetation and meat in an incipient stage of
decomposition. This fungus was at one time regarded as an algal, at
another as animal; but it is much more probable that it is a low
condition of some common mould. The readiness with which the spores of
fungi floating in the atmosphere adhere to and establish themselves on
all putrid or corrupt substances is manifest in the experience of all
who have had to do with the dressing of wounds, and in this case it is
a matter of the greatest importance that, as much as possible,
atmospherical contact should be avoided.

Recently a case occurred at the Botanic Gardens at Edinburgh which was
somewhat novel. The assistant to the botanical professor was preparing
for demonstration some dried specimens of a large puff-ball, filled
with the dust-like spores, which he accidentally inhaled, and was for
some time confined to his room under medical attendance from the
irritation they caused. This would seem to prove that the spores of
some fungi are liable, when inhaled in large quantities, to derange
the system and become dangerous; but under usual and natural
conditions such spores are not likely to be present in the atmosphere
in sufficient quantity to cause inconvenience. In the autumn a very
large number of basidiospores must be present in the atmosphere of
woods, and yet there is no reason to believe that it is more unhealthy
to breathe the atmosphere of a wood in September or October than in
January or May. Dreadful effects are said to be produced by a species
of black rust which attacks the large South of Europe reed, _Arundo
donax_. This is in all probability the same species with that which
attacks _Arundo phragmitis_ in this country, the spores of which
produce violent headaches and other disorders amongst the labourers
who cut the reeds for thatching. M. Michel states that the spores from
the parasite on _Arundo donax_, either inhaled or injected, produce
violent papular eruption on the face, attended with great swelling,
and a variety of alarming symptoms which it is unnecessary to
particularize, in various parts of the body.[K] Perhaps if _Sarcina_
should ultimately prove to be a fungus, it may be added to the list of
those which aggravate, if they are not the primary cause of, disease
in the human subject.

II. What influences can be attributed to fungi upon animals other than
man? Clearly instinct preserves animals from many dangers. It may be
presumed that under ordinary circumstances there is not much fear of a
cow or a sheep poisoning itself in a pasture or a wood. But under
extraordinary circumstances it is not only possible, but very
probable, that injuries may occur. For instance, it is well known that
not only rye and wheat, but also many of the grasses, are liable to
infection from a peculiar form of fungus called "ergot." In certain
seasons this ergot is much more common than others, and the belief is
strong in those who ought to know something of the subject from
experience, viz., farmers and graziers, that in such seasons it is not
uncommon for cattle to slip their young through feeding on ergotized
grass. Then, again, it is fairly open to inquiry whether, in years
when "red rust" and "mildew" are more than usually plentiful on
grasses, these may not be to a certain extent injurious. Without
attempting to associate the cattle plague in any way with fungi on
grass, it is nevertheless a most remarkable coincidence that the year
in which the cattle disease was most prevalent in this country was one
in which there was--at least in some districts--more "red rust" on
grasses than we ever remember to have seen before or since; the
clothes of a person walking through the rusty field soon became
orange-coloured from the abundance of spores. Graziers on this point
again seem to be generally agreed, that they do not think "red rust"
has been proved to be injurious to cattle. The direct influence of
fungi on quadrupeds, birds, reptilia, &c., seems to be infinitesimally
small.

Insects of various orders have been observed from time to time to
become the prey of fungi.[L] That known at Guadaloupe under the name
of _La Guêpe Végétale_, or vegetable wasp, has been often cited as
evidence that, in some instances at least, the fungus attacks the
insect whilst still living. Dr. Madianna states that he has noticed
the wasp still living with its incumbrance attached to it, though
apparently in the last stage of existence, and seeming about to perish
from the influence of its destructive parasite.[M] This fungus is
called by Tulasne _Torrubia sphecocephala_.[N] About twenty-five
species of this genus of sphæriaceous fungi have been described as
parasitic on insects. Five species are recorded in South Carolina, one
in Pennsylvania, found on the larvæ of the May-bug, and one other
North American species on Nocturnal Lepidoptera, one in Cayenne, one
in Brazil, on the larva of a _Cicada_, and one on a species of ant,
two in the West Indies, one in New Guinea on a species of _Coccus_,
and one on a species of _Vespa_ in Senegal. In Australia two species
have been recorded, and two are natives of New Zealand. Dr. Hooker
found two in the Khassya mountains of India, and one American species
has also been found at Darjeeling. It has long been known that one
species, which has a medicinal repute there, is found in China, whilst
three have been recorded in Great Britain. Opinions are divided as to
whether in these instances the fungus causes or is subsequent to the
death of the insect. It is generally the belief of entomologists that
the death of the insect is caused by the fungus. In the case of
_Isaria sphingum_, which is the conidia form of a species of
_Torrubia_, the moth has been found standing on a leaf, as during
life, with the fungus sprouting from its body.

Other and less perfect forms of fungi also attack insects. During the
summer of 1826, Professor Sebert collected a great many caterpillars
of _Arctia villica_, for the purpose of watching their growth. These
insects on arriving at their full size became quite soft, and then
suddenly died. Soon after they became hard, and, if bent, would easily
break into two pieces. Their bodies were covered with a beautiful
shining white mould. If some of the caterpillars affected with the
parasitic mould were placed on the same tree with those apparently
free from its attack, the latter soon exhibited signs that they also
were attacked in the same manner, in consequence of coming into
contact with each other.[O]

During the spring of 1851, some twelve or twenty specimens were found
from amongst myriads of _Cicada septemdecim_, which, though living,
had the posterior third of the abdominal contents converted into a
dry, powdery, ochreous-yellow compact mass of sporuloid bodies. The
outer coverings of that portion of the insect were loose and easily
detached, leaving the fungoid matter in the form of a cone affixed by
its base to the unaffected part of the abdomen of the insect. The
fungus may commence, says Dr. Leidy, its attacks upon the larva,
develop its mycelium, and produce a sporular mass within the active
pupa, when many are probably destroyed; but should some be only
affected so far as not to destroy the organs immediately essential to
life, they might undergo their metamorphosis into the imago, in which
case they would be affected in the manner previously described.[P]

The common house-fly in autumn is very usually subject to the attacks
of a mouldy fungus called _Sporendonema muscæ_, or _Empusa muscæ_ in
former times, which is now regarded as the terrestrial condition of
one of the _Saprolegniei_.[Q] The flies become sluggish, and at last
fix themselves to some object on which they die, with their legs
extended and head depressed, the body and wings soon becoming covered
with a minute white mould, the joints of which fall on the surrounding
object. Examples are readily distinguished when they settle on windows
and thus succumb to their foe. Mr. Gray says that a similar mould has
been observed on individuals of the wasp family.

A _Gryllotalpa_ was found in a wood near Newark, Delaware, U. S., upon
turning over a log. The insect was seen standing very quietly at the
mouth of its oval cell, which is formed in the earth, having a short
curved tube to the surface. Upon taking it up it exhibited no signs of
movement, though perfectly fresh and lifelike in appearance. On
examining it next morning it still presented no signs of life. Every
part of the insect was perfect, not even the antennæ being broken.
Upon feeling it, it was very hard and resistant, and on making an
incision through the thorax it exhaled a fungoid odour. The insect had
been invaded by a parasitic fungus which everywhere filled the animal,
occupying the position of all the soft tissue, and extending even into
the tarsal joints. It formed a yellowish or cream-coloured compact
mass.[R]

The destructive silk-worm disease, _Botrytis Bassiana_, is also a
fungus which attacks and destroys the living insect, concerning which
an immense deal has been written, but which has not yet been
eradicated. It has also been supposed that a low form or imperfect
condition of a mould has much to do with the disease of bees known as
"foul brood."[S]

_Penicillium Fieberi_, figured by Corda on a beetle, was doubtless
developed entirely after death, with which event it had probably
nothing whatever to do.[T] Sufficient, however, has been written to
show that fungi have an influence on insect life, and this might
be extended to other animal forms, as to spiders, on which one or two
species of _Isaria_ are developed, whilst Dr. Leidy has recorded
observations on _Julus_[U] which may be perused with advantage.
Fish are subject to a mouldy-looking parasite belonging to the
_Saprolegniei_, and a similar form attacks the ova of toads and
frogs. Gold fish in globes and aquaria are very subject to attack
from this mouldy enemy, and although we have seen them recover
under a constant change of water, this is by no means always the
case, for in a few weeks the parasite will usually prevail.

The influence of fungi upon animals in countries other than
European is very little known, except in the case of the species of
_Torrubia_ found on insects, and the diseases to which silkworms are
subject. Instances have been recorded of the occurrence of fungoid
mycelium--for in most it is nothing more--in the tissues of
animals, in the hard structure of bone and shell, in the intestines,
lungs, and other fleshy parts, and in various organs of birds.[V] In
some of the latter cases it has been described as a Mucor, in most it
is merely cells without sufficient character for determination. It is
by no means improbable that fungi may be found in such situations;
the only question with regard to them is whether they are not
accidental, and not the producers of unhealthy or diseased tissues,
even when found in proximity thereto.

There is one phase of the influences of fungi on the lower animals
which must not be wholly passed over, and that is the relation which
they bear to some of the insect tribes in furnishing them with food.
It is especially the case with the _Coleoptera_ that many species seem
to be entirely dependent on fungi for existence, since they are found
in no other situations. Beetle-hunters tell us that old _Polyporei_,
and similar fungi of a corky or woody nature, are always sought after
for certain species which they seek in vain elsewhere,[W] and those
who possess herbaria know how destructive certain minute members of
the animal kingdom are to their choicest specimens, against whose
depredations even poison is sometimes unavailing.

Some of the Uredines, as _Trichobasis suaveolens_ and _Coleosporium
sonchi_, are generally accompanied by a little orange larva which
preys upon the fungus; and in the United States Dr. Bolles informs us
that some species of _Æcidium_ are so constantly infested with this
red larva that it is scarcely possible to get a good specimen, or to
keep it from its sworn enemy. Minute _Anguillidæ_ revel in tufts of
mould, and fleshy Agarics, as they pass into decay, become colonies of
insect life. Small _Lepidoptera_, belonging to the _Tineina_, appear
to have a liking for such _Polyporei_ as _P. sulfureus_ when it
becomes dry and hard, or _P. squamosus_ when it has attained a similar
condition. _Acari_ and _Psocidæ_ attack dried fungi of all kinds, and
speedily reduce them to an unrecognizable powder.

III. What are the influences exerted by fungi on other plants? This is
a broad subject, but withal an important one, since these influences
act indirectly on man as well as on the lower animals. On man,
inasmuch as it interferes with the vegetable portion of his food,
either by checking its production or depreciating its quality. On the
lower animals, since by this means not only is their natural food
deteriorated or diminished, but through it injurious effects are
liable to be produced by the introduction of minute fungi into the
system. These remarks apply mainly to fungi which are parasitic on
living plants. On the other hand, the influence of fungi must not be
lost sight of as the scavengers of nature when dealing with dead and
decaying vegetable matter. Therefore, as in other instances, we have
here also good and bad influences intermingled, so that it cannot be
said that they are wholly evil, or unmixed good.

Wherever we encounter decaying vegetable matter we meet with
fungi, living upon and at the expense of decay, appropriating the
changed elements of previous vegetable life to the support of a new
generation, and hastening disintegration and assimilation with the
soil. No one can have observed the mycelium of fungi at work on old
stumps, twigs, and decayed wood, without being struck with the
rapidity and certainty with which disintegration is being carried on.
The gardener casts on one side, in a pile as rubbish, twigs and
cuttings from his trees, which are useless to him, but which have
all derived much from the soil on which they flourished. Shortly
fungi make their appearance in species almost innumerable, sending
their subtle threads of mycelium deep into the tissues of the
woody substance, and the whole mass teems with new life. In this
metamorphosis as the fungi flourish so the twigs decay, for the new
life is supported at the expense of the old, and together the
destroyers and their victims return as useful constituents to the
soil from whence they were derived, and form fresh pabulum for a
succeeding season of green leaves and sweet flowers. In woods and
forests we can even more readily appreciate the good offices of
fungi in accelerating the decay of fallen leaves and twigs which
surround the base of the parent trees. In such places Nature is left
absolutely to her own resources, and what man would accomplish in
his carefully attended gardens and shrubberies must here be done
without his aid. What we call decay is merely change; change of
form, change of relationship, change of composition; and all these
changes are effected by various combined agencies--water, air,
light, heat, these furnishing new and suitable conditions for the
development of a new race of vegetables. These, by their vigorous
growth, continue what water and oxygen, stimulated by light and
heat, had begun, and as they flourish for a brief season on the fallen
glories of the past summer, make preparation for the coming spring.

Unfortunately this destructive power of fungi over vegetable tissues
is too often exemplified in a manner which man does not approve. The
dry rot is a name which has been given to the ravages of more than one
species of fungus which flourishes at the expense of the timber it
destroys. One of these forms of dry rot fungus is _Merulius
lacrymans_, which is sometimes spoken of as if it were the only one,
though perhaps the most destructive in houses. Another is _Polyporus
hybridus_, which attacks oak-built vessels;[X] and these are not the
only ones which are capable of mischief. It appears that the dry rot
fungus acts indirectly on the wood, whose cells are saturated with its
juice, and in consequence lose their lignine and cellulose, though
their walls suffer no corrosion. The different forms of decay in wood
are accompanied by fungi, which either completely destroy the tissue,
or alter its nature so much by the abstraction of the cellulose and
lignine, that it becomes loose and friable. Thus fungi induce the
rapid destruction of decaying wood. These are the conclusions
determined by Schacht, in his memoir on the subject.[Y]

We may allude, in passing, to another phase of destructiveness in the
mycelium of fungi, which traverse the soil and interfere most
injuriously with the growth of shrubs and trees. The reader of
journals devoted to horticulture will not fail to notice the constant
appeals for advice to stop the work of fungi in the soil, which
sometimes threatens vines, at others conifers, and at others
rhododendrons. Dead leaves, and other vegetable substances, not
thoroughly and completely decayed, are almost sure to introduce this
unwelcome element.

Living plants suffer considerably from the predations of parasitic
species, and foremost amongst these in importance are those which
attack the cereals. The corn mildew and its accompanying rust are
cosmopolitan, as far as we know, wherever corn is cultivated, whether
in Australia or on the slopes of the Himalayas. The same may also be
said of smut, for _Ustilago_ is as common in Asia and America as in
Europe. We have seen it on numerous grasses as well as on barley from
the Punjab, and a species different from _Ustilago maydis_ on the male
florets of maize from the same locality. In addition to this, we learn
that in 1870 one form made its appearance on rice. It was described as
constituting in some of the infested grains a whitish, gummy,
interlaced, ill-defined, thread-like mycelium, growing at the expense
of the tissues of the affected organs, and at last becoming converted
into a more or less coherent mass of spores, of a dirty green colour,
on the exterior of the deformed grains. Beneath the outer coating the
aggregated spores are of a bright orange red; the central portion has
a vesicular appearance, and is white in colour.[Z] It is difficult to
determine from the description what this so-called _Ustilago_ may be,
which was said to have affected a considerable portion of the standing
rice crop in the vicinity of Diamond Harbour.

Bunt is another pest (_Tilletia caries_) which occupies the whole
farinaceous portion of the grains of wheat. Since dressing the seed
wheat has been so widely adopted in this country, this pest has been
of comparatively little trouble. Sorghum and the small millets, in
countries where these are cultivated for food, are liable to attacks
from allied parasites. Ergot attacks wheat and rice as well as rye,
but not to such an extent as to have any important influence upon the
crop. Two or three other species of fungi are sometimes locally
troublesome, as _Dilophospora graminis_, and _Septoria nodorum_ on
wheat, but not to any considerable extent. In countries where maize is
extensively grown it has not only its own species of mildew
(_Puccinia_), but also one of the most enormous and destructive
species of _Ustilago_.

A singular parasite on grasses was found by Cesati in Italy, in 1850,
infesting the glumes of _Andropogon_.[a] It received the name of
_Cerebella Andropogonis_, but it never appears to have increased and
spread to such an extent as was at first feared.

Even more destructive than any of these is the potato disease[b]
(_Peronospora infestans_), which is, unfortunately, too well known to
need description. This disease was at one time attributed to various
causes, but long since its ascertained source has been acknowledged to
be a species of white mould, which also attacks tomatoes, but less
vigorously. De Bary has given considerable attention to this disease,
and his opinions are clearly detailed in his memoir on _Peronospora_,
as well as in his special pamphlet on the potato disease.[c] One sees
the cause of the epidemic, he says, in the diseased state of the
potato itself, produced either accidentally by unfavourable conditions
of soil and atmosphere, or by a depravation that the plant has
experienced in its culture. According to these opinions, the
vegetation of the parasite would be purely accidental, the disease
would be independent of it, the parasite would be able frequently even
to spare the diseased organs. Others see in the vegetation of the
_Peronospora_ the immediate or indirect cause of the various symptoms
of the disease; either that the parasite invades the stalks of the
potato, and in destroying them, or, so to speak, in poisoning them,
determines a diseased state of the tubercles, or that it introduces
itself into all the organs of the plant, and that its vegetation is
the immediate cause of all the symptoms of the disease that one meets
with in any organ whatever. His observations rigorously proved that
the opinions of the latter were those only which were well founded.
All the alterations seen on examining spontaneous individuals are
found when the _Peronospora_ is sown in a nourishing plant. The most
scrupulous examination demonstrates the most perfect identity between
the cultivated and spontaneous individuals as much in the organization
of the parasite as in the alteration of the plant that nourishes it.
In the experiments that he had made he affirms that he never observed
an individual or unhealthy predisposition of the nourishing plant. It
appeared to him, on the contrary, that the more the plant was healthy,
the more the mould prospered.

We cannot follow him through all the details of the growth and
development of the disease, or of his experiments on this and allied
species, which resulted in the affirmation that the mould immediately
determines the disease of the tubercles as well as that of the leaves,
and that the vegetation of the _Peronospora_ alone determines the
redoubtable epidemic to which the potato is exposed.[d] We believe
that this same observer is still engaged in a series of observations,
with the view, if possible, of suggesting some remedy or mitigation of
the disease.

Dr. Hassall pointed out, many years since, the action of fungous
mycelium, when coming in contact with cellular tissue, of inducing
decomposition, a fact which has been fully confirmed by Berkeley.

Unfortunately there are other species of the same genus of moulds which
are very destructive to garden produce. _Peronospora gangliformis_, B.,
attacks lettuces, and is but too common and injurious. _Peronospora
effusa_, Grev., is found on spinach and allied plants. _Peronospora
Schleideniana_, D. By., is in some years very common and destructive
to young onions, and field crops of lucerne are very liable to attack
from _Peronospora trifoliorum_, D. By.

The vine crops are liable to be seriously affected by a species of
mould, which is but the conidia form of a species of _Erysiphe_. This
mould, known under the name of _Oidium Tuckeri_, B., attacks the vines
in hothouses in this country, but on the Continent the vineyards often
suffer severely[e] from its depredations; unfortunately, not the only
pest to which the vine is subject, for an insect threatens to be even
more destructive.

Hop gardens suffer severely, in some years, from a similar disease; in
this instance the mature or ultimate form is perfected. The hop mildew
is _Sphærotheca Castagnei_, Lév., which first appears as whitish
mouldy blotches on the leaves, soon becoming discoloured, and
developing the black receptacles on either surface of the leaf. These
may be regarded as the cardinal diseases of fungoid origin to which
useful plants are subject in this country.

Amongst those of less importance, but still troublesome enough to
secure the anathemas of cultivators, may be mentioned _Puccinia Apii_,
Ca., often successful in spoiling beds of celery by attacking the
leaves; _Cystopus candidus_, Lév., and _Glæosporium concentricum_,
Grev., destructive to cabbages and other cruciferous plants;
_Trichobasis Fabæ_, Lév., unsparing when once established on beans;
_Erysiphe Martii_, Lév., in some seasons a great nuisance to the crop
of peas.

Fruit trees do not wholly escape, for _Roestelia cancellata_, Tul.,
attacks the leaves of the pear. _Puccinia prunorum_ affects the leaves
of almost all the varieties of plum. Blisters caused by _Ascomyces
deformans_, B., contort the leaves of peaches, as _Ascomyces
bullatus_, B., does those of the pear, and _Ascomyces juglandis_, B.,
those of the walnut. Happily we do not at present suffer from
_Ascomyces pruni_, Fchl., which, on the Continent, attacks young
plum-fruits, causing them to shrivel and fall. During the past year
pear-blossoms have suffered from what seems to be a form of
_Helminthosporium pyrorum_, and the branches are sometimes infected
with _Capnodium elongatum_; but orchards in the United States have a
worse foe in the "black knot,"[f] which causes gouty swellings in the
branches, and is caused by the _Sphæria morbosa_ of Schweinitz.

Cotton plants in India[g] were described by Dr. Shortt as subject to
the attacks of a kind of mildew, which from the description appeared
to be a species of _Erysiphe_, but on receiving specimens from India
for examination, we found it to be one of those diseased conditions of
tissue formerly classed with fungi under the name of _Erineum_; and a
species of Torula attacks cotton pods after they are ripe. Tea leaves
in plantations in Cachar have been said to suffer from some sort of
blight, but in all that we have seen insects appear to be the
depredators, although on the decaying leaves _Hendersonia theicola_,
Cooke, establishes itself.[h] The coffee plantations of Ceylon suffer
from the depredations of _Hemiliea vastatrix_, as well as from
insects.[i] Other useful plants have also their enemies in parasitic
fungi.

Olive-trees in the south of Europe suffer from the attacks of a
species of _Antennaria_, as do also orange and lemon trees from a
_Capnodium_, which covers the foliage as if with a coating of soot. In
fact most useful plants appear to have some enemy to contend with, and
it is fortunate, not only for the plant, but its cultivators, if this
enemy is less exacting than is the case with the potato, the vine, and
the hop.

Forestry in Britain is an insignificant interest compared to what
it is in some parts of Europe, in the United States, and in our
Indian possessions. In these latter places it becomes a matter of
importance to inquire what influence fungi exert on forest trees.
It may, however, be predicated that the injury caused by fungi is far
outstripped by insects, and that there are not many fungi which
become pests in such situations. Coniferous trees may be infested
with the species of _Peridermium_, which are undoubtedly injurious,
_Peridermium elatinum_, Lk., distorting and disfiguring the silver
fir, as _Peridermium Thomsoni_, B.,[j] does those of _Abies
Smithiana_ in the Himalayas. This species occurred at an elevation of
8,000 feet. The leaves become reduced in length one-half, curved,
and sprinkled, sometimes in double rows, with the large sori of
this species, which gives the tree a strange appearance, and at
length proves fatal, from the immense diversion of nutriment requisite
to support a parasite so large and multitudinous. The dried specimens
have a sweet scent resembling violets. In Northern Europe _Cæoma
pinitorquum_, D. By., seems to be plentiful and destructive. All
species of juniper, both in Europe and the United States, are
liable to be attacked and distorted by species of _Podisoma_[k] and
_Gymnosporangium_. _Antennaria pinophila_, Fr., is undoubtedly
injurious, as also are other species of _Antennaria_, which probably
attain their more complete development in _Capnodium_, of which
_Capnodium Citri_ is troublesome to orange-trees in the south of
Europe, and other species to other trees. How far birch-trees are
injured by _Dothidea betulina_, Fr., or _Melampsora betulina_, Lév.,
or poplars and aspens by _Melampsora populina_, Lév., and _Melampsora
tremulæ_, Lév., we cannot say. The species of _Lecythea_ found on
willow leaves have decidedly a prejudicial effect on the growth of
the affected plant.

Floriculture has to contend with many fungoid enemies, which sometimes
commit great ravages amongst the choicest flowers. Roses have to
contend against the two forms of _Phragmidium mucronatum_ as well as
_Asteroma Rosæ_. Still more disastrous is a species of _Erysiphei_,
which at first appears like a dense white mould. This is named
_Sphærotheca pannosa_. Nor is this all, for _Peronospora sparsa_, when
it attacks roses in conservatories, is merciless in its exactions.[l]
Sometimes violets will be distorted and spoiled by _Urocystis Violæ_.
The garden anemone is freely attacked by _Æcidium quadrifidum_.
Orchids are liable to spot from fungi on the leaves, and recently the
whole of the choicest hollyhocks have been threatened with destruction
by a merciless foe in _Puccinia malvacearum_. This fungus was first
made known to the world as an inhabitant of South America many years
ago. It seems next to have come into notoriety in the Australian
colonies. Then two or three years ago we hear of it for the first time
on the continent of Europe, and last year for the first time in any
threatening form in our own islands. During the present year its
ravages are spreading, until all admirers of hollyhocks begin to feel
alarm lest it should entirely exterminate the hollyhock from
cultivation. It is common on wild mallows, and cotton cultivators must
be on the alert, for there is a probability that other malvaceous
plants may suffer.

A writer in the "Gardener's Chronicle" has proposed a remedy for the
hollyhock disease, which he hopes will prove effectual. He says, "This
terrible disease has now, for twelve months, threatened the complete
annihilation of the glorious family of hollyhock, and to baffle all
the antidotes that the ingenuity of man could suggest, so rapidly does
it spread and accomplish its deadly work. Of this I have had very sad
evidence, as last year at this time I had charge of, if not the
largest, one of the largest and finest collections of hollyhocks
anywhere in cultivation, which had been under my special care for
eleven years, and up to within a month of my resigning that position I
had observed nothing uncommon amongst them; but before taking my final
leave of them I had to witness the melancholy spectacle of bed after
bed being smitten down, and amongst them many splendid seedlings,
which had cost me years of patience and anxiety to produce. And
again, upon taking a share and the management of this business,
another infected collection fell to my lot, so that I have been doing
earnest battle with this disease since its first appearance amongst
us, and I must confess that, up to a very short time back, I had come
in for a great deal the worst of the fight, although I had made use of
every agent I could imagine as being likely to aid me, and all that
many competent friends could suggest. But lately I was reminded of
Condy's patent fluid, diluted with water, and at once procured a
bottle of the green quality, and applied it in the proportion of a
large tablespoonful to one quart of water, and upon examining the
plants dressed, twelve hours afterwards, was delighted to find it had
effectually destroyed the disease (which is easily discernible, as
when it is living and thriving it is of a light grey colour, but when
killed it becomes of a rusty black). Further to test the power at
which the plant was capable of bearing the antidote without injury, I
used it double the strength. This dose was instant death to the pest,
leaving no trace of any injury to the foliage. As to its application,
I advocate sponging in all dressings of this description. Syringing is
a very ready means, but very wasteful. No doubt sponging consumes more
time, but taking into consideration the more effectual manner in which
the dressing can be executed alone, it is in the end most economical,
especially in regard to this little parasite. I have found it
difficult by syringing, as it has great power of resisting and
throwing off moisture, and if but a very few are left living, it is
astonishing how quickly it redistributes itself. I feel confident,
that by the application of this remedy in time another season, I shall
keep this collection clean. I believe planting the hollyhock in large
crowded beds should be avoided, as I have observed the closer they are
growing the more virulently does the disease attack them, whereas
isolated rows and plants are but little injured."[m]

The "Gardener's Chronicle" has also sounded a note of warning that a
species of Uredine has been very destructive to pelargoniums at the
Cape of Good Hope. Hitherto these plants have not suffered much in
this country from parasites. Besides these, there are many other less
troublesome parasites, such as _Uredo filicum_, on ferns; _Puccinia
Lychnidearum_, on leaves of sweet-william; _Uredo Orchidis_, on leaves
of orchids, &c.

If we would sum up the influences of fungi in a few words, it could be
done somewhat in the following form.

Fungi exert a deleterious influence--

      On _Man_,

        When eaten inadvertently.
        By the destruction of his legitimate food.
        In producing or aggravating skin diseases.

      On _Animals_,

        By deteriorating or diminishing their food supplies.
        By establishing themselves as parasites on some species.

      On _Plants_,

        By hastening the decay of timber.
        By establishing themselves as parasites.
        By impregnating the soil.

But it is not proved that they produce epidemic diseases in man or
animals, or that the dissemination of their multitudinous spores in
the atmosphere has any appreciable influence on the health of the
human race. Hence their association with cholera, diarrhoea, measles,
scarlatina, and the manifold ills that flesh is heir to, as producing
or aggravating causes, must, in the present state of our knowledge and
experience, be deemed apocryphal.

   [A] A detailed account of the peculiar properties of this fungus and
       its employment as a narcotic will be found in Cooke's "Seven
       Sisters of Sleep," p. 337. It is figured in Greville's
       "Scottish Cryptogamic Flora," plate 54.

   [B] Pour chaque 500 grammes de champignons coupes en morceaux
       d'assez mediocre grandeur, il faut un litre d'eau acidulée par
       deux ou trois cuillerées de vinaigre, ou deux cuillerées de sel
       gris. Dans le cas ou l'on n'aurait que de l'eau à sa
       disposition, il faut la renouveler une ou deux fois. On
       laisse les champignons macérer dans le liquids pendant deux
       heures entières, puis on les lave à grande eau. Ils sont
       alors mis dans de l'eau froide qu'on porte à l'ébullition,
       et après un quart d'heure ou une demi-heure, on les retire, on
       les lave, on les essuie, et ou les apprête soit comme un
       mets spécial, et ils comportent les mêmes assaisonnements
       que les autres, soit comme condiment.--_Morel Traité des
       Champignons_, p. lix. Paris, 1865.

   [C] Smith's "Chart of Poisonous Fungi," fig. 10.

   [D] Ibid. fig. 27. It would be well to become acquainted with all
       these figures.

   [E] "Skin Diseases of Parasitic Origin," by Dr. Tilbury Fox. London,
       1863.

   [F] Robin, "Hist. Nat. des Végétaux Parasites." Paris, 1853.
       Kuchenmeister, "Animal and Vegetable Parasites of the Human
       Body." London, Sydenham Society, 1857.

   [G] Berkeley, in "Intellectual Observer," Nov., 1862. "Mycetoma," II.
       Vandyke Carter, 1874.

   [H] Hallier and Zurn, "Zeitschrift fur Parasitenkunde." Jena,
       1869-71.

   [I] Dr. Lauder Lindsay, "On Microscopical and Clinical Characters of
       Cholera Evacuations," reprinted from "Edinburgh Medical
       Journal," February and March, 1856; also "Clinical Notes on
       Cholera," by W. Lauder Lindsay, M.D., F.L.S., in "Association
       Medical Journal" for April 14, 1854.

   [J] "Microscopic Examinations of Air," from the "Ninth Annual Report
       of the Sanitary Commissioner," Calcutta, 1872.

   [K] "Gardener's Chronicle," March 26, 1864.

   [L] Gray, G., "Notices of Insects that are Known to Form the Bases of
       Fungoid Parasites." London, 1858.

   [M] Halsey, "Ann. Lyceum," New York, 1824, p. 125.

   [N] Tulasne, "Selecta Fung. Carp." vol. iii. p. 17.

   [O] "Berlin Entom. Zeitung," 1858, p. 178.

   [P] "Smithsonian Contributions to Knowledge," v. p. 53.

   [Q] "Wiegmann Archiv." 1835, ii. p. 354; "Ann. Nat. Hist." 1841,
       405.

   [R] Leidy, "Proc. Acad. Nat. Sci. Phil." 1851, p. 204.

   [S] "Gardener's Chronicle," November 21, 1868.

   [T] Corda, "Prachtflora," pl. ix.

   [U] Leidy, "Fauna and Flora within Living Animals," in "Smithsonian
       Contributions to Knowledge."

   [V] Murie, in "Monthly Microscopical Journal" (1872), vii. p. 149.

   [W] See genus _Mycetophagus_, "Stephen's Manual Brit. Coleopt." p.
       132.

   [X] Sowerby's "Fungi," plates 289 and 387, fig. 6.

   [Y] Schacht, "Fungous Threads in the Cells of Plants," in
       Pringsheim's "Jahrbuch." Berlin, 1863.

   [Z] "Proceedings of the Agri. Hort. Soc. of India" (1871), p. 85.

   [a] "Gardener's Chronicle" (1852), p. 643, with fig.

   [b] Berkeley, "On the Potato Murrain," in "Jour. Hort. Soc." vol. i.
       (1846), p. 9.

   [c] De Bary, "Die gegenwartig herrschende Kartoffelkrankheit."

   [d] De Bary, "Memoir on Peronospora," in "Annales des Sci. Nat."

   [e] "Reports of H. M. Secretaries of Embassy and Legation on the
       Effects of the Vine Disease on Commerce, 1859;" "Reports of H.
       M. Secretaries of Embassy, &c., on Manufactures and Commerce,
       Vine Disease in Bavaria and Switzerland, 1859," pp. 54 and 62.

   [f] C. H. Peek, "On the Black Knot," in "Quekett Microscopical
       Journal," vol. iii. p. 82.

   [g] Cooke, "Microscopic Fungi," p. 177.

   [h] "Grevillea," i. p. 90.

   [i] "Gardener's Chronicle," 1873.

   [j] "Gardener's Chronicle," 1852, p. 627, with fig.

   [k] "Podisoma Macropus," Hook, "Journ. Bot." vol. iv. plate xii. fig.
       6.

   [l] Berkeley, in "Gardener's Chronicle," 1862, p. 308.

   [m] "Gardener's Chronicle," August 22, 1874, p. 243.



XI.

HABITATS.


It commonly happens that one of the first inquiries which the student
seeks to have answered, after an interest is excited in fungi,
is--Where, and under what circumstances, are they to be found? The
inexperienced, indeed, require some guide, or much labour will be
expended and patience lost in seeking microscopic forms in just such
places as they are least likely to inhabit. Nor is it wholly
unprofitable or uninteresting for others, who do not claim to be
students, to summarize the habitats of these organisms, and learn how
much the circumstances of their immediate surrounding elements
influence production. For reasons which will at once be recognized by
the mycologist, the most satisfactory method of study will be somewhat
that of the natural groups into which fungi are divided.

AGARICINI.--There is such a close affinity between all the genera of
this group that it will be a manifest advantage to take together all
those fleshy pileate fungi, the fruit of which is borne on folded
plates or gills. It must be premised of this group that, for the
majority, shade, a moderate amount of moisture, and steady warmth, but
not too great heat, are required. A stroll through a wood in autumn
will afford good evidence of the predilection of _Agaricini_, as well
as some smaller groups, for such spots. A larger proportion will be
found in woods, where shade is afforded, than on open heaths or
pastures. These wood-loving forms will consist, again, of those which
appear on the soil, and those which are found on rotten stumps and
decaying trees. Many of those which grow on trees have a lateral
stem, or scarcely any stem at all. It may be remarked, that some
species which spring from the soil delight most in the shelter of
particular trees. The Agarics of a beech wood will materially differ
largely from those in an oak wood, and both will differ from those
which spring up beneath coniferous trees.

It may be accepted as true of the largest proportion of terrestrial
species, that if they do not spring directly from rotten leaves, and
vegetable débris in the last stage of decay, the soil will be rich in
vegetable humus. A few only occur on sandy spots. The genus
_Marasmius_ is much addicted to dead leaves; _Russula_, to open
places in woods, springing immediately from the soil. _Lactarius_
prefers trees, and when found in exposed situations, occurs mostly
under the shadow of trees.[A] _Cantharellus_, again, is a woodland
genus, many of the species loving to grow amongst grass or moss,
and some as parasites on the latter. _Coprinus_ is not a genus much
addicted to woods, but is rather peculiar in its attachment to
man--if such expression, or one even implying domesticity, might
be employed--farmyards, gardens, dunghills, the base of old gateposts
and railings, in cellars, on plaster walls, and even on old damp
carpets. _Hygrophorus_ loves "the open," whether pastures, lawns,
heaths, commons, or up the slopes of mountains, nearly to the top of
the highest found in Great Britain. _Cortinarius_ seems to have a
preference for woods, whilst _Bolbitius_ affects dung, or a rich
soil. _Lentinus_, _Panus_, _Lenzites_, and _Schizophyllum_ all grow on
wood. Coming to the subgenera of _Agaricus_, we find _Pleurotus_,
_Crepidotus_, _Pluteus_, _Collybia_, _Pholiota_, _Flammula_,
_Hypholoma_, and some species of _Psathyra_ growing on wood, old
stumps, or charcoal; _Amanita_, _Tricholoma_, and _Hebeloma_ most
attached to woods; _Clitocybe_ and _Mycena_ chiefly amongst leaves;
_Nolanea_ amongst grass; _Omphalia_ and _Galera_ chiefly in swampy
places; _Lepiota_, _Leptonia_, _Psalliota_, _Stropharia_, _Psilocybe_,
and _Psathyrella_ mostly in open places and pastures; _Deconica_
and _Panæolus_ mostly on dung; _Entoloma_ and _Clitopilus_ chiefly
terrestrial, and the rest variable.

Of special habitats, we may allude to _Nyctalis_, of which the species
are parasitic on dead fungi belonging to the genus _Russula_. One or
two species of _Agaricus_, such as _Agaricus tuberosus_ and _Agaricus
racemosus_, P., grow on decaying Agarics, whilst _Agaricus Loveianus_
flourishes on _Agaricus nebularis_ even before it is thoroughly
decayed. A few species grow on dead fir cones, others on old ferns,
&c. _Agaricus cepoestipes_, Sow., probably of exotic origin, grows on
old tan in hothouses. _Agaricus caulicinalis_, Bull, flourishes on old
thatch, as well as twigs, &c. _Agaricus juncicola_, Fr., affects dead
rushes in boggy places, whilst _Agaricus affricatus_, Fr., and
_Agaricus sphagnicola_, B., are attached to bog moss in similar
localities. Some few species are almost confined to the stems of
herbaceous plants. _Agaricus petasatus_, Fr., _Agaricus cucumis_, P.,
and _Paxillus panuoides_, F., have a preference for sawdust. _Agaricus
carpophilus_, Fr., and _Agaricus balaninus_, P., have a predilection
for beech mast. _Agaricus urticoecola_, B. and Br., seems to confine
itself to nettle roots. _Coprinus radians_, Fr., makes its appearance
on plaster walls, _Coprinus domesticus_, Fr., on damp carpets. The
only epizoic species, according to M. Fries, is _Agaricus cerussatus
v. nauseosus_, which has been met with in Russia on the carcase of a
wolf; this, however, might have been accidental. Persoon described
_Agaricus Neapolitanus_, which was found growing on coffee-grounds at
Naples; and more recently Viviani has described another species,
_Agaricus Coffeæ_, with rose-coloured spores, found on old fermenting
coffee-grounds at Genoa.[B] Tratinnick figures a species named
_Agaricus Markii_, which was found in wine casks in Austria. A
_Coprinus_ has, both in this country and on the Continent, been found,
after a very short time, on the dressing of wounds, where there has
been no neglect. A curious case of this kind, which at the time
excited great interest, occurred some fifty years since at St.
George's Hospital. Some species appear to confine themselves to
particular trees, some to come up by preference on soil in garden
pots. Certain species have a solitary, others a gregarious habit, and,
of the latter, _Agaricus grammopodius_, Bull, _Agaricus gambosus_,
Fr., _Marasmius oreades_, Fr., and some others grow in rings. Hence it
will be seen that, within certain limits, there is considerable
variation in the habitats of the _Agaricini_.

_Boleti_ do not differ much from _Agaricini_ in their localization.
They seem to prefer woods or borders of woods to pastures, seldom
being found in the latter. One species, _B. parasiticus_, Bull, grows
on old specimens of _Scleroderma_, otherwise they are for the most
part terrestrial.

_Polypori_ also have no wide range of habitat, except in choice of
trees on which to grow, for the majority of them are corticolous. The
section _Mesopus_, which has a distinct central stem, has some species
which prefer the ground. _Polyporus tuberaster_, P., in Italy springs
from the _Pietra funghaia_,[C] and is cultivated for food as well as
_Polyporus avellanus_, which is reared from charred blocks of cob-nut
trees.

In other genera of the _Polyporei_ similar habitats prevail. _Merulius
lacrymans_, Fr., one form of dry rot, occurs in cellars, and too often
on worked timber; whilst _Merulius himantoides_, Fr., is much more
delicate, sometimes running over plants in conservatories.

HYDNEI.--There is nothing calling for special note on the habitats of
these fungi. The stipitate species of _Hydnum_ are some of them found
in woods, others on heaths, one on fir-cones, while the rest have
similar habitats to the species of _Polyporus_.

AURICULARINI.--The genera _Hymenochoete_, _Stereum_, and _Corticium_,
with some species of _Thelephora_, run over corticated or decorticated
wood; other species of _Thelephora_ grow on the ground. The Pezizoid
forms of _Cyphella_ and _Solenia_, like species of _Peziza_, sometimes
occur on bark, and of the former genus some on grasses and others on
moss.

CLAVARIEI.--The interesting, often brightly-coloured, tufts of
_Clavaria_ are usually found amongst grass, growing directly from the
ground. Only in rare instances do they occur on dead leaves or
herbaceous stems. _Calocera_ probably should be classed with the
_Tremellini_, to which its structure seems more closely allied. The
species are developed on wood. The species of _Typhula_ and
_Pistillaria_ are small, growing chiefly on dead herbaceous plants.
One or two are developed from a kind of _Sclerotium_, which is in fact
a compact perennial mycelium.

TREMELLINI.--These curious gelatinous fungi are, with rare exceptions,
developed on branches or naked wood; _Tremella versicolor_, B. and
Br., one of the exceptions, being parasitic on a species of
_Corticium_, and _Tremella epigæa_, B. and Br., spreading over the
naked soil. This completes our rapid survey of the habitats of the
_Hymenomycetes_. Very few of them are really destructive to
vegetation, for the Agarics and Polypori found on growing trees are
seldom to be seen on vigorous, but rather on dead branches or
partly-decayed trunks.

The GASTEROMYCETES are far less numerous in species, and also in
individuals, but their habitats are probably more variable. The
_Hypogæi_, or subterranean species, are found either near the surface
or buried in the soil, usually in the neighbourhood of trees.

PHALLOIDEI.--In most cases the species prefer woody places. They are
mostly terrestrial, and have the faculty of making their presence
known, even when not seen, by the fetid odour which many of them
exhale. Some of them occur in sandy spots.

PODAXINEI.--These resemble in their localities the _Trichogastres_.
Species of _Podaxon_ affect the nests of Termites in tropical
countries.[D] Others are found growing amongst grass.

TRICHOGASTRES.--These are chiefly terrestrial. The rare but curious
_Batarrea phalloides_, P., has been found on sand-hills, and in
hollow trees. _Tulostoma mammosum_, Fr., occurs on old stone walls,
growing amongst moss. _Geaster striatus_, D. C., was at one time
usually found on the sand of the Denes at Great Yarmouth. Although
_Lycoperdon giganteum_, Batsch, occurs most frequently in pastures, or
on hedge banks in fields, we have known it to occur annually for
some consecutive years in a garden near London. The species of
_Scleroderma_ seem to prefer a sandy soil. _Agloeocystis_ is rather
an anomalous genus, occurring on the fruit heads of _Cyperus_, in
India. _Broomeia_ occurs at the Cape on rotten wood.

MYXOGASTRES.--Rotten wood is one of the most favoured of matrices on
which these fungi develop themselves; some of them, however, are
terrestrial. _Æthalium_ will grow on spent tan and other substances.
Species of _Diderma_ flourish on mosses, jungermanniæ, grass, dead
leaves, ferns, &c. _Angioridium sinuosum_, Grev., will run over
growing plants of different kinds, and _Spumaria_, in like manner,
encrusts living grasses. _Badhamia_ not only flourishes on dead wood,
but one species is found on the fading leaves of coltsfoot which are
still green. _Craterium_ runs over almost any substance which lies in
its way. _Licea perreptans_ was found in a cucumber frame heated with
spent hops. One or two _Myxogastres_ have been found on lead, or even
on iron which had been recently heated. Sowerby found one on cinders,
in one of the galleries of St. Paul's Cathedral.

NIDULARIACEI grow on the ground, or on sticks, twigs, chips, and other
vegetable substances, such as sawdust, dung, and rotten wood.

The CONIOMYCETES consist of two sections, which are based on their
habitats. In one section the species are developed on dead or dying
plants, in the other they are parasitic on living plants. The former
includes the _Sphæronemei_, which are variable in their proclivities,
although mostly preferring dead herbaceous plants and the twigs of
trees. The exceptions are in favour of _Sphæronema_, some of which are
developed upon decaying fungi. In the large genera, _Septoria_,
_Ascochyta_, _Phyllosticta_, _Asteroma_, &c., the favourite habitat is
fading and dying leaves of plants of all kinds. In the majority of
cases these fungi are not autonomous, but are merely the stylosporous
conditions of _Sphæria_. They are mostly minute, and the stylospores
are of the simplest kind. The _Melanconiei_ have a preference for the
twigs of trees, bursting through the bark, and expelling the spores in
a gelatinous mass. A few of them are foliicolous, but the exceptions
are comparatively rare, and are represented chiefly in _Gloeosporium_,
species of which are found also on apples, peaches, nectarines, and
other fruits. The _Torulacei_ are superficial, having much of the
external appearance of the black moulds, and like them are found on
decaying vegetable substances, old stems of herbaceous plants, dead
twigs, wood, stumps of trees, &c. The exceptions are in favour of such
species as _Torula sporendonema_, which is the red mould of cheese,
and also occurs on rats' dung, old glue, &c., and _Sporendonema
Muscæ_, which is only the conidia of a species of _Achlya_. One
species of _Bactridium_ is parasitic on the hymenium of _Peziza_, and
_Echinobotryum atrum_, on the flocci of black moulds.

In the other section of _Coniomycetes_ the species are parasitic upon,
and destructive to, living plants, very seldom being found on
really dead substances, and even in such rare cases undoubtedly
developed during the life of the tissues. Mostly the ultimate stage
of these parasites is exhibited in the ruptured cuticle, and the
dispersion of the dust-like spores; but in _Tilletia caries_,
_Thecaphora hyalina_, and _Puccinia incarcerata_, they remain enclosed
within the fruit of the foster-plant. The different genera exhibit
in some instances a liking for plants of certain orders on which
to develop themselves. _Peridermium_ attacks the _Coniferæ_;
_Gymnosporangium_ and _Podisoma_ the different species of Juniper;
_Melampsora_ chiefly the leaves of deciduous trees; _Roestelia_
attaches itself to pomaceous trees, whilst _Graphiola_ affects the
_Palmaceæ_, and _Endophyllum_ the succulent leaves of houseleek. In
_Æcidium_ a few orders seem to be more liable to attack than
others, as the _Compositæ_, _Ranunculaceæ_, _Leguminosæ_, _Labiatæ_,
&c., whilst others, as the _Graminaceæ_, _Ericaceæ_, _Malvaceæ_,
_Cruciferæ_, are exempt. There are, nevertheless, very few natural
orders of phanerogamous plants in which some one or more species,
belonging to this section of the _Coniomycetes_, may not be found; and
the same foster-plant will occasionally nurture several forms.
Recent investigations tend to confirm the distinct specific
characters of the species found on different plants, and to prove
that the parasite of one host will not vegetate upon another,
however closely allied. This admission must not, however, be
accepted as universally applicable, and therefore it should not be
assumed, because a certain parasite is found developed on a special
host, that it is distinct, unless distinctive characters, apart from
habitat, can be detected. _Æcidium compositarum_ and _Æcidium
ranunculacearum_, for instance, are found on various composite and
ranunculaceous plants, and as yet no sufficient evidence has been
adduced to prove that the different forms are other than varieties
of one of the two species. On the other hand, it is not improbable
that two species of _Æcidium_ are developed on the common berberry,
as De Bary has indicated that two species of mildew, _Puccinia
graminis_, and _Puccinia straminis_, are found on wheat.

HYPHOMYCETES.--The moulds are much more universal in their habitats,
especially the _Mucedines_. The _Isariacei_ have a predilection for
animal substances, though not exclusively. Some species occur on dead
insects, others on decaying fungi, and the rest on sticks, stems, and
rotten wood. The _Stilbacei_ have also similar habitats, except that
the species of _Illosporium_ seem to be confined to parasitism on
lichens. The black moulds, _Dematiei_, are widely diffused, appearing
on herbaceous stems, twigs, bark, and wood in most cases, but also on
old linen, paper, millboard, dung, rotting fruit, &c., whilst forms of
_Cladosporium_ and _Macrosporium_ are met with on almost every kind of
vegetable substance in which the process of decay has commenced.

_Mucedines_, in some instances, have not been known to appear on
more than one kind of matrix, but in the far greater number of cases
they nourish on different substances. _Aspergillus glaucus_ and
_Penicillium crustaceum_ are examples of these universal _Mucedines_.
It would be far more difficult to mention substances on which
these moulds are never developed than to indicate where they have been
found. With the species of _Peronospora_ it is different, for these
are truly parasitic on living plants, and, as far as already known,
the species are confined to certain special plants, and cannot be
made to vegetate on any other. The species which causes the potato
murrain, although liable to attack the tomato, and other species of
_Solanaceæ_, does not extend its ravages beyond that natural order,
whilst _Peronospora parasitica_ confines itself to cruciferous plants.
One species is restricted to the _Umbelliferæ_, another, or perhaps
two, to the _Leguminosæ_, another to _Rubiaceæ_, two or three to
_Ranunculaceæ_, and two or three to _Caryophyllaceæ_. All the
experiments made by De Bary seem to prove that the species of
_Peronospora_ will only flourish on certain favoured plants, to the
exclusion of all others. The non-parasitic moulds are scarcely
exclusive. In _Oidium_ some species are parasitic, but probably all
the parasitic forms are states of _Erysiphe_, the non-parasitic
alone being autonomous; of these one occurs on _Porrigo lupinosa_,
others on putrefying oranges, pears, apples, plums, &c., and one
on honeycomb. _Acrospeira_ grows in the interior of sweet chestnuts,
and we have seen a species growing within the hard testa of the
seeds of _Guilandina Bondue_, from India, to which there was no
external opening visible, and which was broken with considerable
difficulty. Several _Mucedines_ are developed on the dung of
various animals, and seldom on anything else.

The _Physomycetes_ consist of two orders, _Antennariei_ and
_Mucorini_, which differ from each other almost as much in habitat as
in external appearance. The former, if represented by _Antennaria_,
runs over the green and fading leaves of plants, forming a dense black
stratum, like a congested layer of soot; or in _Zasmidium_, the common
cellar fungus, runs over the walls, bottles, corks, and other
substances, like a thick sooty felt. In the _Mucorini_, as in the
_Mucedines_, there is usually less restriction to any special
substance. _Mucor mucedo_ occurs on bread, paste, preserves, and
various substances; other species of _Mucor_ seem to have a preference
for dung, and some for decaying fungi, but rotting fruits are nearly
sure to support one or other of the species. The two known species of
the curious genus _Pilobolus_, as well as _Hydrophora_, are confined
to dung. _Sporodinia_, _Syzygites_, &c., nourish on rotten Agarics,
where they pass through their somewhat complicated existence.

The _Ascomycetes_ contain an immense number of species, and in general
terms we might say that they are found everywhere. The _Tuberacei_ are
subterraneous, with a preference for calcareous districts. The
_Perisporiacei_ are partly parasitical and partly not. The _Erysiphei_
include those of the former which flourish at the expense of the green
parts of roses, hops, maples, poplars, peas, and many other plants,
both in Europe and in North America, whilst in warmer latitudes the
genus _Meliola_ appears to take their place.

The _Elvellacei_ are fleshy fungi, of which the larger forms are
terrestrial; _Morchella_, _Gyromitra_, and _Helvella_ mostly growing
in woods, _Mitrula_, _Spathularia_, and _Leotia_ in swampy places, and
_Geoglossum_ amongst grass. The very large genus _Peziza_ is divided
into groups, of which _Aleuriæ_ are mostly terrestrial. This group
includes nearly all the large-sized species, although a few belong to
the next. _Lachneæ_ are partly terrestrial and partly epiphytal, the
most minute species being found on twigs and leaves of dead plants. In
_Phialea_ the species are nearly entirely epiphytal, as is also the
case in _Helotium_ and allied genera. Some species of _Peziza_ are
developed from the curious masses of compact mycelium called
_Sclerotia_. A few are rather eccentric in their habitats. _P.
viridaria_, _P. domestica_, and _P. hoemastigma_, grow on damp walls;
_P. granulata_ and some others on dung. _Peziza Bullii_ was found
growing on a cistern. _P. theleboloides_ appears in profusion on spent
hops. _P. episphæria_, _P. clavariarum_, _P. vulgaris_, _Helotium
pruinosum_, and others are parasitic on old fungi. One or two species
of _Helotium_ grow on submerged sticks, so as to be almost aquatic, a
circumstance of rare occurrence in fungi. Other _Discomycetes_ are
similar in their habitats to the _Elvellacei_. The group to which the
old genus _Ascobolus_ belongs is in a great measure confined to the
dung of various animals, although there are two or three lignicolous
species; and _Ascophanus saccharinus_ was first found on old leather,
_Ascophanus testaceus_ on old sacking, &c. _Ascomyces_ is, perhaps,
the lowest form which ascomycetous fungi assume, and the species are
parasitic on growing plants, distorting the leaves and fruit,
constituting themselves pests to the cultivators of peach, pear, and
plum trees.

The _Sphæriacei_ include a very large number of species which grow on
rotten wood, bark, sticks, and twigs; another group is developed on
dead herbaceous stems; yet another is confined to dead or dying
leaves. One genus, _Torrubia_, grows chiefly on insects; _Hypomyces_
is parasitic on dead fungi; _Claviceps_ is developed from ergot,
_Poronia_ on dung, _Polystigma_ on living leaves, as well as some
species of _Stigmatea_ and _Dothidea_. Of the genus _Sphæria_, a
considerable number are found on dung, now included by some authors
under _Sordaria_ and _Sporormia_, genera founded, as we think, on
insufficient characters. A limited number of species are parasitic on
lichens, and one species only is known to be aquatic.

[Illustration: FIG. 109.--_Torrubia militaris_ on pupa of a moth.]

We have thus rapidly, briefly, and casually indicated the habitats to
which the majority of the larger groups of fungi are attached,
regarding them from a systematic point of view. There is, however,
another aspect from which we might approach the subject, taking
the host or matrix, or in fact the habitat, as the basis, and
endeavouring to ascertain what species of fungi are to be found in
such positions. This has partly been done by M. Westendorp;[E] but
every year adds considerably to the number of species, and what might
have been moderately accurate twelve years since can scarcely be so
now. To carry this out fully a special work would be necessary, so
that we shall be content to indicate or suggest, by means of a few
illustrations, the forms of fungi, often widely distinct in
structure and character, to be found in the same locality.

The stems of herbaceous plants are favourite habitats for minute
fungi. The old stems of the common nettle, for example, perform the
office of host to about thirty species.[F] Of these about nine are
_Pezizæ_, and there are as many sphæriaceous fungi, whilst three
species of _Dendryphium_, besides other moulds, select this plant.
Some of these have not hitherto been detected growing on any other
stems, such as _Sphæria urticæ_ and _Lophiostoma sex-nucleatum_, to
which we might add _Peziza fusarioides_ and _Dendryphium griseum_.
These do not, however, include the whole of the fungi found on the
nettle, since others are parasitic upon its living green parts. Of
these may be named _Æcidium urticæ_ and _Peronospora urticæ_, as well
as two species described by Desmazières as _Fusisporium urticæ_ and
_Septoria urticæ_. Hence it will be seen how large a number of fungi
may attach themselves to one herbaceous plant, sometimes whilst
living, but most extensively when dead. This is by no means a solitary
instance, but a type of what takes place in many others. If, on the
other hand, we select such a tree as the common lime, we shall find
that the leaves, twigs, branches, and wood bear, according to M.
Westendorp,[G] no less than seventy-four species of fungi, and of
these eleven occur on the leaves. The spruce fir, according to the
same authority, nourishes one hundred and fourteen species, and the
oak not less than two hundred.

It is curious to note how fungi are parasitic upon each other in some
instances, as in that of _Hypomyces_, characteristic of the genus, in
which sphæriaceous fungi make hosts of dead _Lactarii_, &c. We have
already alluded to _Nyctalis_, growing on decayed _Russulæ_, to
_Boletus parasiticus_, flourishing on old _Scleroderma_, and to
_Agaricus Loveianus_, on the pileus of _Agaricus nebularis_. To these
we may add _Torrubia ophioglossoides_ and _T. capitata_, which
flourish on decaying _Elaphomyces_, _Stilbum tomentosum_ on old
_Trichia_, _Peziza Clavariarum_ on dead _Clavaria_, and many others,
the mere enumeration of which would scarcely prove interesting. A very
curious little parasite was found by Messrs. Berkeley and Broome, and
named by them _Hypocrea inclusa_, which makes itself a home in the
interior of truffles. Mucors and moulds flourish on dead and decaying
Agarics, and other fleshy forms, in great luxuriance and profusion.
_Mucor ramosus_ is common on _Boletus luridus_, and _Syzygites
megalocarpus_ on Agarics, as well as _Acrostalagmus cinnabarinus_. A
very curious little parasite, _Echinobotryum atrum_, occurs like
minute nodules on the flocci of black moulds. _Bactridium Helvellæ_
usurps the fructifying disc of species of _Peziza_. A small
_Sphinctrina_ is found both in Britain and the United States on old
_Polypori_. In _Sphæria nigerrima_, _Nectria episphæria_, and two or
three others, we have examples of one sphæriaceous fungus growing
upon another.

Mr. Phillips has recently indicated the species of fungi found by him
on charcoal beds in Shropshire,[H] but, useful as it is, that only
refers to one locality. A complete list of all the fungi which have
been found growing on charcoal beds, burnt soil, or charred wood,
would be rather extensive. The fungi found in hothouses and stoves are
also numerous, and often of considerable interest from the fact that
they have many of them never been found elsewhere. Those found in
Britain,[I] for instance, are excluded from the British Flora as
doubtful, because, growing upon or with exotic plants, they are deemed
to be of exotic origin, yet in very few cases are they known to be
inhabitants of any foreign country. Some species found in such
localities are not confined to them, as _Agaricus coepestipes_,
_Agaricus cristatus_, _Æthalium vaporarium_, &c. It is somewhat
singular that certain species have a predilection for growing in
proximity with other plants with which they do not appear to have any
more intimate relation. Truffles, for instance, in association with
oaks, _Peziza lanuginosa_ under cedar-trees, _Hydnangium carneum_
about the roots of _Eucalypti_, and numerous species of _Agaricini_,
which are only found under trees of a particular kind. As might be
anticipated, there is no more fertile habitat for fungi than the dung
of animals, and yet the kinds found in such locations belong to but a
few groups. Amongst the _Discomycetes_, a limited number of the genus
_Peziza_ are fimicolous, but the allied genus _Ascobolus_, and its own
immediate allies, include amongst its species a large majority that
are found on dung. If we take the number of species at sixty-four,
there are only seven or eight which do not occur on dung, whilst
fifty-six are fimicolous. The species of _Sphæria_ which are found on
the same substances are also closely allied, and some Continental
authors have grouped them under the two proposed genera _Sporormia_
and _Sordaria_, whilst Fuckel[J] proposes a distinct group of
_Sphæriacei_, under the name of _Fimicoli_, in which he includes as
genera _Coprolepa_, _Hypocopra_, _Delitschia_, _Sporormia_,
_Pleophragmia_, _Malinvernia_, _Sordaria_, and _Cercophora_. The two
species of _Pilobolus_, and some of _Mucor_, are also found on dung,
_Isaria felina_ on that of cats, _Stilbum fimetarium_ and a few other
moulds, and amongst Agarics some species of _Coprinus_. Animal
substances are not, as a rule, prolific in the production of fungi.
_Ascobolus saccharinus_ and one or two others have been found upon old
leather. _Onygena_ of two or three species occurs on old horn, hoofs,
&c. Cheese, milk, &c., afford a few forms, but the largest number
infest dead insects, either under the mouldy form of _Isaria_ or the
more perfect condition of _Torrubia_, and occasionally under other
forms.

Robin[K] has recorded that three species of _Brachinus_, of the order
Coleoptera, have been found infected, whilst living, with a minute
yellow fungus which he calls _Laboulbenia Rougeti_, and the same
species has been noted on other beetles. _Torrubia Melolonthæ_[L] has
been described by Tulasne as occurring on the maybug or cockchafer,
which is allied to, if not identical with, _Cordyceps Ravenelii_, B.
and C., and also that described and figured by M. Fougeroux de
Bondaroy.[M] _Torrubia curculionum_, Tul., occurs on several species
of beetles, and seems to be by no means uncommon in Brazil and Central
America. _Torrubia coespitosa_, Tul., which may be the same as
_Cordyceps Sinclairi_, B.,[N] is found on the larvæ of _Orthoptera_ in
New Zealand, _Torrubia Miquelii_ on the larvæ of _Cicada_ in Brazil,
and _Torrubia sobolifera_ on the pupæ of _Cicada_ in the West Indies.
A romantic account is given of this in an extract cited by Dr. Watson
in his communication to the Royal Society.[O] "The vegetable fly is
found in the island Dominica, and (excepting that it has no wings)
resembles the drone, both in size and colour, more than any other
English insect. In the month of May it buries itself in the earth and
begins to vegetate. By the latter end of July, the tree is arrived at
its full growth, and resembles a coral branch, and is about three
inches high, and bears several little pods, which, dropping off,
become worms, and from thence flies, like the English caterpillar."
_Torrubia Taylori_, which grows from the caterpillar of a large moth
in Australia, is one of the finest examples of the genus. _Torrubia
Robertsii_, from New Zealand, has long been known as attacking the
larva of _Hepialus virescens_. There are several other species on
larvæ of different insects, on spiders, ants, wasps, &c., and one or
two on mature Lepidoptera, but the latter seem to be rare.

That fungi should make their appearance and flourish in localities and
conditions generally considered inimical to vegetable life is no less
strange than true. We have already alluded to the occurrence of some
species on spent tan, and some others have been found in locations as
strange. We have seen a yellow mould resembling _Sporotrichum_ in the
heart of a ball of opium, also a white mould appears on the same
substance, and more than one species is troublesome in the opium
factories of India. A mould made its appearance some years since in a
copper solution employed for electrotyping in the Survey Department of
the United States,[P] decomposing the salt, and precipitating the
copper. Other organisms have appeared from time to time in various
inorganic solutions, some of which were considered destructive to
vegetable life, and it is not improbable that some of these organisms
were low conditions of mould. It may well occasion some surprise that
fungi should be found growing within cavities wholly excluded from the
external air, as in the hollow of filberts, and the harder shelled
nuts of _Guilandina_, in the cavities of the fruit of tomato, or in
the interior of an egg. It is scarcely less extraordinary that
_Hypocrea inclusa_ should flourish in the interior of a kind of
truffle.

From the above it will be concluded that the habitats of fungi are
exceedingly variable, that they may be regarded as almost universal
wherever decaying vegetable matter is found, and that under some
conditions animal substances, especially of vegetable feeders, such as
insects, furnish a pabulum for their development.

A very curious and interesting inquiry presents itself to our minds,
which is intimately related to this subject of the habitats of fungi.
It shapes itself into a sort of "puzzle for the curious," but at the
same time one not unprofitable to think about. How is the occurrence
of new and before unknown forms to be accounted for in a case like the
following?[Q]

It was our fortune--good fortune as far as this investigation was
concerned--to have a portion of wall in our dwelling persistently damp
for some months. It was close to a cistern which had become leaky. The
wall was papered with "marbled" paper, and varnished. At first there
was for some time nothing worthy of observation, except a damp
wall--decidedly damp, discoloured, but not by any means mouldy. At
length, and rather suddenly, patches of mould, sometimes two or three
inches in diameter, made their appearance. These were at first of a
snowy whiteness, cottony and dense, just like large tufts of cotton
wool, of considerable expansion, but of miniature elevation. They
projected from the paper scarcely a quarter of an inch. In the course
of a few weeks the colour of the tufts became less pure, tinged with
an ochraceous hue, and resembling wool rather than cotton, less
beautiful to the naked eye, or under a lens, and more entangled. Soon
after this darker patches made their appearance, smaller, dark olive,
and mixed with, or close to, the woolly tufts; and ultimately similar
spots of a dendritic character either succeeded the olive patches, or
were independently formed. Finally, little black balls, like small pin
heads, or grains of gunpowder, were found scattered about the damp
spots. All this mouldy forest was more than six months under constant
observation, and during that period was held sacred from the
disturbing influences of the housemaid's broom and duster.

Curiosity prompted us from the first to submit the mouldy denizens of
the wall to the microscope, and this curiosity was increased week by
week, on finding that none of the forms found vegetating on nearly two
square yards of damp wall could be recognized as agreeing specifically
with any described moulds with which we were acquainted. Here was a
problem to be solved under the most favourable conditions, a forest of
mould indoors, within a few yards of the fireside, growing quite
naturally, and all strangers. Whence could these new forms proceed?

The cottony tufts of white mould, which were the first to appear, had
an abundant mycelium, but the erect threads which sprang from this
were for a long time sterile, and closely interlaced. At length
fertile threads were developed in tufts, mixed with the sterile
threads. These fruit-bearers were shorter and stouter, more sparingly
branched, but beset throughout nearly their whole length with short
patent, alternate branchlets. These latter were broadest towards the
apex, so as to be almost clavate, and the extremity was beset with two
or three short spicules. Each spicule was normally surmounted by an
obovate spore. The presence of fertile threads imparted the ochraceous
tint above alluded to. This tint was slight, and perhaps would not
have been noticed, but from the close proximity of the snow-white
tufts of barren threads. The fertile flocci were decumbent, probably
from the weight of the spores, and the tufts were a little elevated
above the surface of the matrix. This mould belonged clearly to the
_Mucedines_, but it hardly accorded well with any known genus,
although most intimately related to _Rhinotrichum_, in which it was
placed as _Rhinotrichum lanosum_.[R]

The white mould having become established for a week or two, small
blackish spots made their appearance on the paper, sometimes amongst
thin patches of the mould, and sometimes outside them. These spots, at
first cloudy and indefinite, varied in size, but were usually less
than a quarter of an inch in diameter. The varnish of the paper was
afterwards pushed off in little translucent flakes or scales, an
erect olivaceous mould appeared, and the patches extended to nearly an
inch in diameter, maintaining an almost universal circular form. This
new mould sometimes possessed a dirty reddish tint, but was commonly
dark olive. There could be no mistake about the genus to which this
mould belonged; it had all the essential characters of _Penicillium_.
Erect jointed threads, branched in the upper portion in a fasciculate
manner, and bearing long beaded threads of spores, which formed a
tassel-like head, at the apex of each fertile thread. Although at
first reminded of _Penicillium olivaceum_, of Corda, by the colour of
this species, it was found to differ in the spores being oblong
instead of globose, and the ramifications of the flocci were
different. Unable again to find a described species of _Penicillium_
with which this new mould would agree, it was described under the name
of _Penicillium chartarum_.[S]

Almost simultaneously, or but shortly after the perfection of the
spores of _Penicillium_, other and very similar patches appeared,
distinguished by the naked eye more particularly by their dendritic
form. This peculiarity seemed to result from the dwarfed habit of the
third fungus, since the varnish, though cracked and raised, was not
cast off, but remained in small angular fragments, giving to the spots
their dendritic appearance, the dark spores of the fungus protruding
through the fissures. This same mould was also found in many cases
growing in the same spots amongst _Penicillium chartarum_, but whether
from the same mycelium could not be determined.

The distinguishing features of this fungus consist in an extensive
mycelium of delicate threads, from which arise numerous erect
branches, bearing at the apex dark brown opaque spores. Sometimes the
branches were again shortly branched, but in the majority of instances
were single. The septate spores had from two to four divisions, many
of them divided again by cross septa in the longitudinal direction of
the spore, so as to impart a muriform appearance. As far as the
structure and appearance of the spores are concerned, they resembled
those of _Sporidesmium polymorphum_, under which name specimens were
at first published,[T] but this determination was not satisfactory.
The mycelium and erect threads are much too highly developed for a
good species of _Sporidesmium_, although the name of _Sporidesmium
alternaria_ was afterwards adopted. In fresh specimens of this fungus,
when seen _in situ_ by a half-inch objective, the spores appear to be
moniliform, but if so, all attempts to see them so connected, when
separated from the matrix, failed. On one occasion, a very immature
condition was examined, containing simple beaded, hyaline bodies,
attached to each other by a short neck. The same appearance of beaded
spores, when seen _in situ_, was recognized by a mycological friend,
to whom specimens were submitted for confirmation.[U]

The last production which made its appearance on our wall-paper burst
through the varnish as little black spheres, like grains of gunpowder.
At first the varnish was elevated by pressure from beneath, then
the film was broken, and the little blackish spheres appeared. These
were, in the majority of cases, gregarious, but occasionally a few of
the spheres appeared singly, or only two or three together. As the
whole surface of the damp paper was covered by these different
fungi, it was scarcely possible to regard any of them as isolated,
or to declare that one was not connected with the mycelium of the
others. The little spheres, when the paper was torn from the wall,
were also growing from the under surface, flattened considerably by
the pressure. The spherical bodies, or perithecia, were seated on a
plentiful hyaline mycelium. The walls of the perithecia, rather more
carbonaceous than membranaceous, are reticulated, reminding one of
the conceptacles of _Erysiphe_, to which the perithecia bear
considerable resemblance. The ostiolum is so obscure that we doubt
its existence, and hence the closer affinity of the plant to the
_Perisporiacei_ than to the _Sphæriacei_. The interior of the
perithecium is occupied by a gelatinous nucleus, consisting of
elongated cylindrical asci, each enclosing eight globose hyaline
sporidia, with slender branched paraphyses. A new genus has been
proposed for this and another similar form, and the present
species bears the name of _Orbicula cyclospora_.[V]

The most singular circumstance connected with this narrative is the
presence together of four distinctly different species of fungi, all
of them previously unknown and undescribed, and no trace amongst them
of the presence of any one of the very common species, which would be
supposed to develop themselves under such circumstances. It is not at
all unusual for _Sporocybe alternata_, B., to appear in broad black
patches on damp papered walls, but in this instance not a trace was to
be found. What were the peculiar conditions present in this instance
which led to the manifestation of four new forms, and none of the old
ones? We confess that we are unable to account satisfactorily for the
mystery, but, at the same time, feel equally unwilling to invent
hypotheses in order to conceal our own ignorance.

   [A] These predilections must be accepted as general, to which there
       will be exceptions.

   [B] Viviani, "I Funghi d'Italia."

   [C] Badham's "Esculent Funguses," Ed. i. pp. 42, 116.

   [D] An excellent white Agaric occurs on ant nests in the
       Neilgherries, and a curious species is found in a similar
       position in Ceylon.

   [E] Westendorp, "Les Cryptogams après leurs stations naturelles."

   [F] Cooke, "On Nettle Stems and their Micro-Fungi," in "Journ.
       Quekett Micro. Club," iii. p. 69.

   [G] Westendorp, "Les Cryptogams après leurs stations naturelles,"
       1865.

   [H] "Gardener's Chronicle," 1874.

   [I] W. G. Smith, in "Journ. Botany," March, 1873; Berkeley, in
       "Grevillea," vol. i. p. 88.

   [J] Fuckel, "Symbolæ Mycologicæ," p. 240.

   [K] Robin, "Végét. Parasites," p. 622, t. viii. f. 1, 2.

   [L] Tulasne, "Selecta Fung. Carp." iii. p. 12.

   [M] "Hist. de l'Acad. des Sciences," 1769. Paris, 1772.

   [N] Berkeley, "Crypt. Bot." p. 73; Hooker, "New Zealand Flora," ii.
       338.

   [O] "Philosophical Transactions," liii. (1763), p. 271.

   [P] Berkeley's "Outlines," p. 30.

   [Q] "Popular Science Review," vol. x. (1871), p. 25.

   [R] Specimens of this mould were distributed in Cooke's "Fungi
       Britannici Exsiccati," No. 356, under the name of _Clinotrichum
       lanosum_.

   [S] Cooke's "Handbook of British Fungi," p. 602.

   [T] Cooke's "Fungi Britannici Exsiccati," No. 329, under the name of
       _Sporidesmium polymorphum_ var. _chartarum_.

   [U] This reminds one of Preuss's _Alternaria_, figured in Sturm's
       "Flora;" it has been suggested that the mould, as seen when
       examined under a power of 320 diam., is very much like a
       _Macrosporium_. Again arises the question of the strings of
       spores attached end to end.

   [V] "Handbook of British Fungi," vol. ii. p. 926, No. 2,788.



XII.

CULTIVATION.


The cultivation of fungi in this country for esculent purposes is
confined to a single species, and yet there is no reason why, by a
series of well-conducted experiments, means should not be devised for
the cultivation of others, for instance, _Marasmius orcades_, and the
morel. Efforts have been made on the Continent for the cultivation of
truffles, but the success has hitherto been somewhat doubtful. For the
growth of the common mushroom, very little trouble and care is
required, and moderate success is certain. A friend of ours some years
since was fortunate enough to have one or two specimens of the large
puff-ball, _Lycoperdon giganteum_, growing in his garden. Knowing its
value, and being particularly fond of it when fried for breakfast, he
was anxious to secure its permanence. The spot on which the specimens
appeared was marked off and guarded, so that it was never desecrated
by the spade, and the soil remained consequently undisturbed. Year
after year, so long as he resided on the premises, he counted upon and
gathered several specimens of the puff-ball, the mycelium continuing
to produce them year after year. All parings, fragments, &c., not
utilized of the specimens eaten were cast on this spot to rot, so that
some of the elements might be returned to the soil. This was not true
cultivation perhaps, as the fungus had first established itself, but
it was preservation, and had its reward. It must be admitted, however,
that the size and number of specimens diminished gradually, probably
from exhaustion of the soil. This fungus, though strong, is much
approved by many palates, and its cultivation might be attempted.
Burying a ripe specimen in similar soil, and watering ground with the
spores, has been tried without success.[A]

As to the methods adopted for cultivation of the common mushroom,
it is unnecessary to detail them here, as there are several special
treatises devoted to the subject, in which the particulars are
more fully given than the limits of this chapter will permit.[B]
Recently, M. Chevreul exhibited at the French Academy some splendid
mushrooms, said to have been produced by the following method: he
first develops the mushrooms by sowing spores on a pane of glass,
covered with wet sand; then he selects the most vigorous individuals
from among them, and sows, or plants their mycelium in a cellar in
a damp soil, consisting of gardener's mould, covered with a layer
of sand and gravel two inches thick, and another layer of rubbish from
demolitions, about an inch deep. The bed is watered with a diluted
solution of nitrate of potash, and in about six days the mushrooms
grow to an enormous size.[C] The cultivation of mushrooms for the
market, even in this country, is so profitable, that curious
revelations sometimes crop up, as at a recent trial at the Sheriffs'
Court for compensation by the Metropolitan Railway Company for
premises and business of a nurseryman at Kensington. The Railway had
taken possession of a mushroom-ground, and the claim for compensation
was £716. It was stated in evidence that the profits on mushrooms
amounted to 100 or 150 per cent. One witness said if £50 were
expended, in twelve months, or perhaps in six months, the sum
realized would be £200.

Immense quantities of mushrooms are produced in Paris, as is well
known, in caves, and interesting accounts have been written of visits
to these subterranean mushroom-vaults of the gay city. In one of these
caves, at Montrouge, the proprietor gathers largely every day,
occasionally sending more than 400 pounds weight per day to market,
the average being about 300 pounds. There are six or seven miles' run
of mushroom-beds in this cave, and the owner is only one of a large
class who devote themselves to the culture of mushrooms. Large
quantities of preserved mushrooms are exported, one house sending to
England not less than 14,000 boxes in a year. Another cave near
Frépillon was in full force in 1867, sending as many as 3,000 pounds
of mushrooms to the Parisian markets daily. In 1867, M. Renaudot had
over twenty-one miles of mushroom-beds in one great cave at Méry, and
in 1869 there were sixteen miles of beds in a cave at Frépillon. The
temperature of these caves is so equal that the cultivation of the
mushroom is possible at all seasons of the year, but the best crops
are gathered in the winter.

Mr. Robinson gives an excellent account, not only of the subterranean,
but also of the open-air culture of mushrooms about Paris. The
open-air culture is never pursued in Paris during the summer, and
rarely so in this country.[D] What might be termed the domestic
cultivation of mushrooms is easy, that is, the growth by inexperienced
persons, for family consumption, of a bed of mushrooms in cellars,
wood-houses, old tubs, boxes, or other unconsidered places. Even in
towns and cities it is not impracticable, as horse-dung can always be
obtained from mews and stables. Certainly fungi are never so
harmless, or seldom so delicious, as when collected from the bed, and
cooked at once, before the slightest chemical change or deterioration
could possibly take place.

Mr. Cuthill's advice may be repeated here. He says:--"I must not
forget to remind the cottager that it would be a shilling or two a
week saved to him during the winter, if he had a good little bed of
mushrooms, even for his own family, to say nothing about a shilling or
two that he might gain by selling to his neighbours. I can assure him
mushrooms grow faster than pigs, and the mushrooms do not eat
anything; they only want a little attention. Addressing myself to the
working classes, I advise them, in the first place, to employ their
children or others collecting horse-droppings along the highway, and
if mixed with a little road-sand, so much the better. They must be
deposited in a heap during summer, and trodden firmly. They will heat
a little, but the harder they are pressed the less they will heat.
Over-heating must be guarded against; if the watch or trial stick
which is inserted into them gets too hot for the hand to bear, the
heat is too great, and will destroy the spawn. In that case artificial
spawn must be used when the bed is made up, but this expedient is to
be avoided on account of the expense. The easiest way for a cottager
to save his own spawn would be to do so when he destroys his old bed;
he will find all round the edges or driest parts of the dung one mass
of superior spawn; let him keep this carefully in a very dry place,
and when he makes up his next bed it can then be mixed with his summer
droppings, and will insure a continuance and excellent crop. These
little collections of horse-droppings and road-sand, if kept dry in
shed, hole, or corner, under cover, will in a short time generate
plenty of spawn, and will be ready to be spread on the surface of the
bed in early autumn, say by the middle of September or sooner. The
droppings during the winter must be put into a heap, and allowed to
heat gently, say up to eighty or ninety degrees; then they must be
turned over twice daily to let off the heat and steam; if this is
neglected the natural spawn of the droppings is destroyed. The
cottager should provide himself with a few barrowfuls of strawy dung
to form the foundation of his bed, so that the depth, when all is
finished, be not less than a foot. Let the temperature be up to milk
heat. He will then, when quite sure that the bed will not overheat,
put on his summer droppings. By this time these will be one mass of
natural spawn, having a grey mouldy and thready appearance, and a
smell like that of mushrooms. Let all be pressed very hard; then let
mould, unsifted, be put on, to the thickness of four inches, and
trodden down hard with the feet and watered all over; and the back of
a spade may now be used to make it still harder, as well as to plaster
the surface all over."[E] Mushrooms are cultivated very extensively by
Mr. Ingram, at Belvoir, without artificial spawn. There is a great
riding-house there, in which the litter is ground down by the horses'
feet into very small shreds. These are placed in a heap and turned
over once or twice during the season, when a large quantity of
excellent spawn is developed which, placed in asparagus beds or laid
under thin turf, produces admirable mushrooms, in the latter case as
clean as in our best pastures.[F]

Other species will sometimes be seen growing on mushroom-beds besides
the genuine mushroom, the spawn in such cases being probably
introduced with the materials employed. We have seen a pretty crisped
variety of _Agaricus dealbatus_ growing in profusion in such a place,
and devoured it accordingly. Sometimes the mushrooms will, when in an
unhealthy condition, be subject to the ravages of parasitic species of
mould, or perhaps of _Hypomyces_. _Xylaria vaporaria_ has, in more
than one instance, usurped the place of mushrooms. Mr. Berkeley has
received abundant specimens in the Sclerotioid state, which he
succeeded in developing in sand under a bell glass. Of course under
such conditions there is much loss. The little fairy-ring champignon
is an excellent and useful species, and it is a great pity that some
effort should not be made to procure it by cultivation. In Italy a
kind of _Polyporus_, unknown in this country, is obtained by watering
the _Pietra funghaia_, or fungus stone, a sort of tufa impregnated
with mycelium. The _Polypori_, it is said, take seven days to come to
perfection, and may be obtained from the foster mass, if properly
moistened, six times a year. There are specimens which were fully
developed in Mr. Lee's nursery at Kensington many years since. Another
fungus is obtained from the pollard head of the black poplar. Dr.
Badham says that it is usual to remove these heads at the latter end
of autumn, as soon as the vintage is over, and their marriage with the
vine is annulled; hundreds of such heads are then cut and transported
to different parts; they are abundantly watered during the first
month, and in a short time produce that truly delicious fungus
_Agaricus caudicinus_, which, during the autumn of the year, makes the
greatest show in the Italian market-places. These pollard blocks
continue to bear for from twelve to fourteen years.

Another fungus, which Dr. Badham himself reared (_Polyporus
avellanus_), is procured by singeing, over a handful of straw, a block
of the cob-nut tree, which is then watered and put by. In about a
month the fungi make their appearance, and are quite white, of from
two to three inches in diameter, and excellent to eat, while their
profusion is sometimes so great as entirely to hide the wood from
whence they spring.[G] It has been said that _Boletus edulis_ may be
propagated by watering the ground with a watery infusion of the
plants, but we have no knowledge of this method having been pursued
with success.

The culture of truffles has been partially attempted, on the principle
that, in some occult manner, certain trees produced truffles beneath
their shade. It is true that truffles are found under trees of special
kinds, for Mr. Broome remarks that some trees appear more favourable
to the production of truffles than others. Oak and hornbeam are
specially mentioned; but, besides these, chestnut, birch, box, and
hazel are alluded to. He generally found _Tuber oestivum_ under
beech-trees, but also under hazel, _Tuber macrosporum_ under oaks, and
_Tuber brumale_ under oaks and abele. The men who collect truffles
for Covent Garden Market obtain them chiefly under beech, and in mixed
plantations of fir and beech.[H]

Some notion may be obtained of the extent to which the trade of
truffles is carried in France, when we learn that in the market of Apt
alone about 3,500 pounds of truffles are exposed for sale every week
during the height of the season, and the quantity sold during the
winter reaches upwards of 60,000 pounds, whilst the Department of
Vaucluse yields annually upwards of 60,000 pounds. It may be
interesting here to state that the value of truffles is so great in
Italy that precautions are taken against truffle poachers, much in the
same way as against game poachers in England. They train their dogs so
skilfully that, while they stand on the outside of the truffle
grounds, the dogs go in and dig for the fungi. Though there are
multitudes of species, they bring out those only which are of market
value. Some dogs, however, are employed by botanists, which will hunt
for any especial species that may be shown to them. The great
difficulty is to prevent them devouring the truffles, of which they
are very fond. The best dogs, indeed, are true retrievers.

The Count de Borch and M. de Bornholz give the chief accounts of the
efforts that have been made towards the cultivation of these fungi.
They state that a compost is prepared of pure mould and vegetable soil
mixed with dry leaves and sawdust, in which, when properly moistened,
mature truffles are placed in winter, either whole or in fragments,
and that after the lapse of some time small truffles are found in the
compost.[I] The most successful plan consists in sowing acorns over a
considerable extent of land of a calcareous nature; and when the young
oaks have attained the age of ten or twelve years, truffles are found
in the intervals between the trees. This process was carried on in the
neighbourhood of Loudun, where truffle-beds had formerly existed, but
where they had long ceased to be productive--a fact indicating the
aptitude of the soil for the purpose. In this case no attempt was
made to produce truffles by placing ripe specimens in the earth, but
they sprang up themselves from spores probably contained in the soil.
The young trees were left rather wide apart, and were cut, for the
first time, about the twelfth year after sowing, and afterwards at
intervals of from seven to nine years. Truffles were thus obtained for
a period of from twenty-five to thirty years, after which the
plantations ceased to be productive, owing, it was said, to the ground
being too much shaded by the branches of the young trees. It is the
opinion of the Messrs. Tulasne that the regular cultivation of the
truffle in gardens can never be so successful as this so-called
indirect culture at Loudun, but they think that a satisfactory result
might be obtained in suitable soils by planting fragments of mature
truffles in wooded localities, taking care that the other conditions
of the spots selected should be analogous to those of the regular
truffle-grounds, and they recommend a judicious thinning of the trees
and clearing the surface from brushwood, etc., which prevents at once
the beneficial effects of rain and of the direct sun's rays. A truffle
collector stated to Mr. Broome that whenever a plantation of beech, or
beech and fir, is made on the chalk districts of Salisbury Plain,
after the lapse of a few years truffles are produced, and that these
plantations continue productive for a period of from ten to fifteen
years, after which they cease to be so.

M. Gasparin reported to the jurors of the Paris Exhibition of 1855,
concerning the operations of M. Rousseau, of Carpentras, on the
production of oak truffles in France. The acorns of evergreen and of
common oaks were sown about five yards apart. In the fourth year of
the plantation three truffles were found; at the date of the report
the trees were nine years old, and over a yard in height. Sows were
employed to search for the truffles. Although these plantations
consist both of the evergreen and common oak, truffles cannot be
gathered at the base of the latter species, it so happening that it
arrives later at a state of production. The common oak, however,
produces truffles like the evergreen oak, this report states, for a
great number of the natural truffle-grounds at Vaucluse are planted
with common oaks. It is remarked that the truffles produced from
these are larger but less regular than those of the evergreen oak,
which are smaller, but nearly always spherical. The truffles are
gathered at two periods of the year; in May only white truffles are to
be found, which never blacken and have no odour; they are dried and
sold for seasoning. The black truffles (_Tuber melanosporum_) commence
forming in June, enlarging towards the frosty season; then they become
hard, and acquire all their perfume. They are dug a month before and a
month after Christmas. It is also asserted that truffles are produced
about the vine, or at any rate that the association of the vine is
favourable to the production of truffles, because truffle-plots near
vines are very productive. The observation of this decided M. Rousseau
to plant a row of vines between the oaks. The result of this
experiment altogether does not appear to have been by any means
flattering, for at the end of eight years only little more than
fifteen pounds were obtained from a hectare of land, which, if valued
at 45 francs, would leave very little profit. M. Rousseau also called
attention to a meadow manured (_sic_) with parings of truffles, which
was said to have given prodigious results.

The cultivation of minute fungi for scientific purposes has been
incidentally alluded to and illustrated in foregoing chapters, and
consequently will not require such full and particular details
here. Somewhat intermediately, we might allude to the species of
_Sclerotium_, which are usually compact, externally blackish,
rounded or amorphous bodies, consisting of a cellular mass of the
nature of a concentrated mycelium. Placed in favourable conditions,
these forms of _Sclerotium_ will develop the peculiar species of
fungus belonging to them, but in certain cases the production is more
rapid and easy than in others. In this country, Mr. F. Currey has
been the most successful in the cultivation of _Sclerotia_. The
method adopted is to keep them in a moist, somewhat warm, but
equable atmosphere, and with patience await the results. The
well-known ergot of rye, wheat, and other grasses may be so
cultivated, and Mr. Currey has developed the ergot of the common
reed by keeping the stem immersed in water. The final conditions
are small clavate bodies of the order _Sphæriacei_, belonging to
the genus _Claviceps_. The _Sclerotium_ of the _Eleocharis_ has been
found in this country, but we are not aware that the _Claviceps_
developed from it has been met with or induced by cultivation. One
method recommended for this sort of experiment is to fill a
garden-pot half full of crocks, over which to place sphagnum broken
up until the pot is nearly full, on this to place the _Sclerotia_,
and cover with silver sand; if the pot is kept standing in a pan of
water in a warm room, it is stated that production will ensue.
Ergot of the grasses will not always develop under these conditions,
but perseverance may ultimately ensure success.

A species of _Sclerotium_ on the gills of dead Agarics originates
_Agaricus tuberosus_, another _Agaricus cirrhatus_,[J] but this should
be kept _in situ_ when cultivated artificially, and induced to develop
whilst still attached to the rotten Agarics. _Peziza tuberosa_, in
like manner, is developed from _Sclerotia_, usually found buried in
the ground in company with the roots of _Anemone nemorosa_. At one
time it was supposed that some relationship existed between the roots
of the anemone and the _Sclerotia_. From another _Sclerotium_, found
in the stems of bulrushes, Mr. Currey has developed a species of
_Peziza_, which has been named _P. Curreyana_.[K] This _Peziza_ has
been found growing naturally from the _Sclerotia_ imbedded in the
tissue of common rushes. De Bary has recorded the development of
_Peziza Fuckeliana_ from a _Sclerotium_ of which the conidia take the
form of a species of _Polyactis_. _Peziza ciborioides_ is developed
from a _Sclerotium_ found amongst dead leaves; and recently we have
received from the United States an allied _Peziza_ which originated
from the _Sclerotia_ found on the petals of _Magnolia_, and which has
been named _Peziza gracilipes_, Cooke, from its very slender,
thread-like stem. Other species of _Peziza_ are also known to be
developed from similar bases, and these Fuckel has associated
together under a proposed new genus with the name of _Sclerotinia_.
Two or three species of _Typhula_, in like manner, spring from forms
of _Sclerotium_, long known as _Sclerotium complanatum_ and
_Sclerotium scutellatum_. Other forms of _Sclerotium_ are known, from
one of which, found in a mushroom-bed, Mr. Currey developed _Xylaria
vaporaria_, B., by placing it on damp sand covered with a bell
glass.[L] Others, again, are only known in the sclerotioid state, such
as the _Sclerotium stipitatum_ found in the nests of white ants in
South India.[M] From what is already known, however, we feel justified
in the conclusion that the so-called species of _Sclerotium_ are a
sort of compact mycelium, from which, under favourable conditions,
perfect fungi may be developed. Mr. Berkeley succeeded in raising from
the minute _Sclerotium_ of onions, which looks like grains of coarse
gunpowder, a species of _Mucor_. This was accomplished by placing a
thin slice of the _Sclerotium_ in a drop of water under a glass slide,
surrounded by a pellicle of air, and luted to prevent evaporation and
external influences.[N]

As to the cultivation of moulds and _Mucors_, one great difficulty has
to be encountered in the presence or introduction of foreign spores to
the matrix employed for their development. Bearing this in mind,
extensive cultivations may be made, but the conditions must influence
the decision upon the results. Rice paste has been used with advantage
for sowing the spores of moulds, afterwards keeping them covered from
external influences. In cultivation on rice paste of rare species, the
experimenter is often perplexed by the more rapid growth of the common
species of _Mucor_ and _Penicillium_. Mr. Berkeley succeeded in
developing up to a certain point the fungus of the Madura Foot, but
though perfect sporangia were produced, the further development was
masked by the outgrowth of other species. In like manner, orange
juice, cut surfaces of fruits, slices of potato tubers, etc., have
been employed. Fresh, horse-dung, placed under a bell glass and kept
in a humid atmosphere, will soon be covered with _Mucor_, and in like
manner the growth of common moulds upon decayed fruit may be watched;
but this can hardly be termed cultivation unless the spores of some
individual species are sown. Different solutions have been proposed
for the growth of such conditions as the cells which induce
fermentation, to which yeast plants belong. A fly attacked by _Empusa
muscæ_, if immersed in water, will develop one of the _Saprolegniæ_.

The _Uredines_ and other epiphyllous _Coniomycetes_ will readily
germinate by placing the leaf which bears them on damp sand, or
keeping them in a humid atmosphere. Messrs. Tulasne and De Bary have,
in their numerous memoirs, detailed the methods adopted by them
for different species, both for germination of the pseudospores and
for impregnating healthy foster plants. The germination of the
pseudospores of the species of _Podisoma_ may easily be induced, and
secondary fruits obtained. The germination of the spores of _Tilletia_
is more difficult to accomplish, but this may be achieved. Mr.
Berkeley found no difficulty, and had the stem impregnated as well as
the germen. On the other hand, the pseudospores of _Cystopus_,
when sown in water on a slip of glass, will soon produce the
curious little zoospores in the manner already described.

The sporidia of the _Discomycetes_, and some of the _Sphæriacei_,
germinate readily in a drop of water on a slip of glass, although not
proceeding further than the protrusion of germ-tubes. A form of slide
has been devised for growing purposes, in which the large covering
glass is held in position, and one end of the slip being kept immersed
in a vessel of water, capillary attraction keeps up the supply for an
indefinite period, so that there is no fear of a check from the
evaporation of the fluid. Even when saccharine solutions are employed
this method may be adopted.

The special cultivation of the _Peronosporei_ occupied the attention
of Professor De Bary for a long time, and his experiences are
detailed in his memoir on that group,[O] but which are too long
for quotation here, except his observations on the development of the
threads of _Peronospora infestans_ on the cut surface of the tubers
of diseased potatoes. When a diseased potato is cut and sheltered from
dessication, the surface of the slice covers itself with the mycelium
and conidiiferous branches of _Peronospora_, and it can easily be
proved that these organs originate from the intercellulary tubes of
the brown tissue. The mycelium that is developed upon these slices
is ordinarily very vigorous; it often constitutes a cottony mass of a
thickness of many millimetres, and it gives out conidiiferous
branches, often partitioned, and larger and more branched than those
observed on the leaves. The appearance of these fertile branches
ordinarily takes place at the end of from twenty-four to forty-eight
hours; sometimes, nevertheless, one must wait for many days. These
phenomena are observed in all the diseased tubercles without
exception, so long as they have not succumbed to putrefaction,
which arrests the development of the parasite and kills it.

Young plants of the species liable to attack may be inoculated with
the conidia of the species of _Peronospora_ usually developed on that
particular host, in the same manner that young cruciferous plants,
watered with an infusion of the spores of _Cystopus candidus_, will
soon exhibit evidence of attack from the white rust.

It is to the cultivation and close investigation of the growth and
metamorphoses of the minute fungi that we must look for the most
important additions which have yet to be made to our knowledge of the
life-history of these most complex and interesting organisms.

   [A] Experiments were made at Belvoir, by Mr. Ingram, in the
       cultivation of several species of _Agaricini_, but without
       success, and a similar fate attended some spawn of a very
       superior kind from the Swan River, which was submitted to the
       late Mr. J. Henderson. No result was obtained at Chiswick,
       either from the cultivation of truffles or from the inoculation
       of grass-plots with excellent spawn. Mr. Disney's experiments
       at the Hyde, near Ingatestone, were made with dried truffles,
       and were not likely to succeed. The Viscomte Nôe succeeded in
       obtaining abundant truffles, in an enclosed portion of a wood
       fenced from wild boars, by watering the ground with an infusion
       of fresh specimens; but it is possible that as this took place
       in a truffle country, there might have been a crop without any
       manipulation. Similar trials, and it is said successfully, have
       been made with _Boletus edulis_. Specimens of prepared
       truffle-spawn were sent many years since to the "Gardener's
       Chronicle," but they proved useless, if indeed they really
       contained any reliable spawn.

   [B] Robinson, "On Mushroom Culture," London, 1870. Cuthill, "On the
       Cultivation of the Mushroom," 1861. Abercrombie, "The Garden
       Mushroom; its Culture, &c." 1802.

   [C] This has, however, not been confirmed, and is considered (how
       justly we cannot say) a "canard."

   [D] This method is pursued with great success by Mr. Ingram, at
       Belvoir, and by Mr. Gilbert, at Burleigh.

   [E] Cuthill, "Treatise on the Cultivation of the Mushroom," p. 9.

   [F] Mr. Berkeley lately recommended, at one of the meetings of the
       Horticultural Society at South Kensington, that the railway
       arches should be utilized for the cultivation of mushrooms.

   [G] Badham, "Esculent Funguses," 1st ed. p. 43.

   [H] Broome, "On Truffle Culture," in "Journ. Hort. Soc." i. p. 15
       (1866).

   [I] No faith, however, is, in general, placed on these treatises, as
       they were merely conjectural.

   [J] Dr. Bull has been very successful in developing the _Sclerotium_
       of _Agaricus cirrhatus_.

   [K] Currey, "On Development of _Sclerotium roseum_," in "Journ. Linn.
       Soc." vol. i. p. 148.

   [L] Currey, in "Linn. Trans." xxiv. pl. 25, figs. 17, 26.

   [M] Berkeley, "On Two Tuberiform Veg. Productions from Travancore,"
       in "Trans. Linn. Soc." vol. xxiii. p. 91.

   [N] Berkeley, "On a Peculiar Form of Mildew in Onions," "Journ. Hort.
       Soc." vol. iii p. 91.

   [O] De Bary, "Ann. des Sci. Nat." 4th series, vol. xx.



XIII.

GEOGRAPHICAL DISTRIBUTION.


Unfortunately no complete or satisfactory account can be given of the
geographical distribution of fungi. The younger Fries,[A] with all the
facilities at his disposal which the lengthened experience and large
collections of his father afforded, could only give a very imperfect
outline, and now we can add very little to what he has given. The
cause of this difficulty lies in the fact that the Mycologic Flora of
so large a portion of the world remains unexplored, not only in remote
regions, but even in civilized countries where the Phanerogamic Flora
is well known. Europe, England, Scotland, and Wales are as well
explored as any other country, but Ireland is comparatively unknown,
no complete collection having ever been made, or any at least
published. Scandinavia has also been well examined, and the northern
portions of France, with Belgium, some parts of Germany and Austria,
in Russia the neighbourhood of St. Petersburg, and parts of Italy and
Switzerland. Turkey in Europe, nearly all Russia, Spain, and Portugal
are almost unknown. As to North America, considerable advances have
been made since Schweinitz by Messrs. Curtis and Ravenel, but their
collections in Carolina cannot be supposed to represent the whole of
the United States; the small collections made in Texas, Mexico, etc.,
only serve to show the richness of the country, not yet half
exhausted. It is to be hoped that the young race of botanists in the
United States will apply themselves to the task of investigating the
Mycologic Flora of this rich and fertile region. In Central America
very small and incomplete collections have as yet been made, and the
same may be said of South America and Canada. Of the whole extent of
the New World, only the Carolina States of North America can really be
said to be satisfactorily known. Asia is still less known, the whole
of our vast Indian Empire being represented by the collections made by
Dr. Hooker in the Sikkim Himalayas, and a few isolated specimens from
other parts. Ceylon has recently been removed from the category of the
unknown by the publication of its Mycologic Flora.[B] All that is
known of Java is supplied by the researches of Junghuhn; whilst all
the rest is completely unknown, including China, Japan, Siam, the
Malayan Peninsula, Burmah, and the whole of the countries in the north
and west of India. A little is known of the Philippines, and the
Indian Archipelago, but this knowledge is too fragmentary to be of
much service. In Africa no part has been properly explored, with the
exception of Algeria, although something is known of the Cape of Good
Hope and Natal. The Australasian Islands are better represented in the
Floras published of those regions. Cuba and the West Indies generally
are moderately well known from the collections of Mr. C. Wright, which
have been recorded in the journal of the Linnæan Society, and in the
same journal Mr. Berkeley has described many Australian species.

It will be seen from the above summary how unsatisfactory it must be
to give anything like a general view of the geographical distribution
of fungi, or to estimate at all approximately the number of species on
the globe. Any attempt, therefore, must be made and accepted subject
to the limitations we have expressed.

The conditions which determine the distribution of fungi are not
precisely those which determine the distribution of the higher plants.
In the case of the parasitic species they may be said to follow the
distribution of their foster-plants, as in the case of the rust, smut,
and mildew of the cultivated cereals, which have followed those
grains wherever they have been distributed, and the potato disease,
which is said to have been known in the native region of the potato
plant before it made its appearance in Europe. We might also allude to
_Puccinia malvacearum_, Ca., which was first made known as a South
American species; it then travelled to Australia, and at length to
Europe, reaching England the next year after it was recorded on the
Continent. In the same manner, so far as we have the means of knowing,
_Puccinia Apii_, Ca., was known on the Continent of Europe for some
time before it was detected on the celery plants in this country.
Experience seems to warrant the conclusion that if a parasite affects
a certain plant within a definite area, it will extend in time beyond
that area to other countries where the foster-plant is found. This
view accounts in some part for the discovery of species in this
country, year after year, which had not been recorded before; some
allowance being made for the fact that an increased number of
observers and collectors may cause the search to be more complete, yet
it must be conceded that the migration of Continental species must to
some extent be going on, or how can it be accounted for that such
large and attractive fungi as _Sparassis crispa_, _Helvellas gigas_,
and _Morchella crassipes_ had never been recorded till recently, or
amongst parasitic species such as the two species of _Puccinia_ above
named? In the same manner it is undoubtedly true that species which at
one time were common gradually become somewhat rare, and at length
nearly extinct. We have observed this to apply to the larger species
as well as to the microscopic in definite localities. For instance,
_Craterellus cornucopioides_ some ten years ago appeared in one wood,
at a certain spot, by hundreds, whereas during the past three or four
years we have failed to find a single specimen. As many years since,
and in two places, where the goat's-beard was abundant, as it is now,
we found nearly half the flowering heads infested with _Ustilago
receptaculorum_, but for the past two or three years, although we have
sought it industriously, not a single specimen could be found. It is
certain that plants found by Dickson, Bolton, and Sowerby, have not
been detected since, whilst it is not improbable that species common
with us may be very rare fifty years hence. In this manner it would
really appear that fungi are much more liable than flowering plants to
shift their localities, or increase and diminish in number.

The fleshy fungi, _Agaricini_ and _Boleti_ especially, are largely
dependent upon the character of woods and forests. When the
undergrowth of a wood is cleared away, as it often is every few years,
it is easy to observe a considerable difference in the fungi. Species
seem to change places, common ones amongst a dense undergrowth are
rare or disappear with the copsewood, and others not observed before
take their place. Some species, too, are peculiar to certain woods,
such as beech woods and fir woods, and their distribution will
consequently depend very much on the presence or absence of such
woods. Epiphytal species, such as _Agaricus ulmarius_, _Agaricus
mucidus_, and a host of others, depend on circumstances which do not
influence the distribution of flowering plants. It may be assumed that
such species as flourish in pastures and open places are subject to
fewer adverse conditions than those which affect woods and forests.

Any one who has observed any locality with reference to its Mycologic
Flora over a period of years will have been struck with the difference
in number and variety caused by what may be termed a "favourable
season," that is, plenty of moisture in August with warm weather
afterwards. Although we know but little of the conditions of
germination in Agarics, it is but reasonable to suppose that a
succession of dry seasons will considerably influence the flora of any
locality. Heat and humidity, therefore, are intimately concerned in
the mycologic vegetation of a country. Fries has noted in his essay
the features to which we have alluded. "The fact," he says, "must not
be lost sight of that some species of fungi which have formerly been
common in certain localities may become, within our lifetime, more and
more scarce, and even altogether cease to grow there. The cause of
this, doubtless, is the occurrence of some change in the physical
constitution of a locality, such as that resulting from the
destruction of a forest, or from the drainage, by ditches and
cuttings, of more or less extensive swamps, or from the cultivation of
the soil--all of them circumstances which cause the destruction of the
primitive fungaceous vegetation and the production of a new one. If we
compare the fungal flora of America with that of European countries,
we observe that the former equals, in its richness and the variety of
its forms, that of the phanerogamous flora; it is probable, however,
that, in the lapse of more or fewer years, this richness will
decrease, in consequence of the extension of cultivation--as is
illustrated, indeed, in what has already taken place in the more
thickly peopled districts, as, for example, in the vicinity of New
York."

Although heat and humidity influence all kinds of vegetation, yet heat
seems to exert a less, and humidity a greater, influence on fungi than
on other plants. It is chiefly during the cool moist autumnal weather
that the fleshy fungi flourish most vigorously in our own country, and
we observe their number to increase with the humidity of the season.
Rain falls copiously in the United States, and this is one of the most
fruitful countries known for the fleshy fungi. Hence it is a
reasonable deduction that moisture is a condition favourable to the
development of these plants. The _Myxogastres_, according to Dr. Henry
Carter, are exceedingly abundant--in individuals, at least, if not in
species--in Bombay, and this would lead to the conclusion that the
members of this group are influenced as much by heat as humidity in
their development, borne out by the more plentiful appearance of the
species in this country in the warmer weather of summer.

In the essay to which we have alluded, Fries only attempts the
recognition of two zones in his estimate of the distribution of fungi,
and these are the temperate and tropical. The frigid zone produces no
peculiar types, and is poor in the number of species, whilst no
essential distinction can be drawn between the tropical and
sub-tropical with our present limited information. Even these two
zones must not be accepted too rigidly, since tropical forms will in
some instances, and under favourable conditions, extend far upwards
into the temperate zone.

"In any region whatever," writes Fries, "it is necessary, in the first
instance, to draw a distinction between its open naked plains and
its wooded tracts. In the level open country there is a more rapid
evaporation of the moisture by the conjoined action of the sun and
wind; whence it happens that such a region is more bare of fungi
than one that is mountainous or covered by woods. On the other hand,
plains possess several species peculiar to themselves; as, for
example, _Agaricus pediades_, certain _Tricholomata_, and, above
all, the family _Coprini_, of which they may be regarded as the
special habitat. The species of this family augment in number, in
any given country, in proportion to the extent and degree of its
cultivation; for instance, they grow more luxuriantly in the
province of Scania, in Sweden--a district farther distinguished
above all others by its cultivation and fertility. In well-wooded
countries moisture is retained a much longer time, and, as a
result, the production of fungi is incomparably greater; and it is
here desirable to make a distinction between the fungi growing in
forests of resinous-wooded trees (_Coniferæ_) and those which
inhabit woods of other trees, for these two descriptions of forests
may be rightly regarded, as to their fungaceous growths, as two
different regions. Beneath the shade of _Coniferæ_, fungi are
earlier in their appearance; so much so, that it often happens they
have attained their full development when their congeners in forests
of non-resinous trees have scarcely commenced their growth. In woods
of the latter sort, the fallen leaves, collected in thick layers, act
as an obstacle to the soaking of moisture into the earth, and
thereby retard the vegetation of fungi; on the other hand, such
woods retain moisture longer. These conditions afford to several
large and remarkable species the necessary time for development. The
beech is characteristic of our own region, but, further north this
tree gives place to the birch. Coniferous woods are, moreover,
divisible into two regions--that of the pines and that of the firs.
The latter is richer in species than the former, because, as is well
known, fir-trees flourish in more fertile and moister soils.
Whether, with respect to the South of Europe, other subdivisions into
regions are required, we know not; still less are we able to
decide on the like question in reference to the countries beyond
Europe."[C]

In very cold countries the higher fungi are rare, whilst in tropical
countries they are most common at elevations which secure a temperate
climate. In Java, Junghuhn found them most prolific at an elevation of
3,000 to 5,000 feet; and in India, Dr. Hooker remarked that they were
most abundant at an elevation of 7,000 to 8,000 feet above the sea
level.

For the higher fungi we must be indebted to the summary made by Fries,
to which we have little to add.

The genus _Agaricus_ occupies the first place, and surpasses, in the
number of species, all the other generic groups known. It appears,
from our present knowledge, that the _Agarici_ have their geographic
centre in the temperate zone, and especially in the colder portion of
that zone. It is a curious circumstance that all the extra-European
species of this genus _Agaricus_ may be referred to various European
subgenera.

In tropical countries it appears that the _Agarici_ occupy only a
secondary position in relation to other genera of fungi, such as
_Polyporus_, _Lenzites_, etc. North America, on the other hand, is
richer in species of _Agaricus_ than Europe; for whilst the majority
of typical forms are common to both continents, America further
possesses many species peculiar to itself. In the temperate zone, so
close is the analogy prevailing between the various countries in
respect to the _Agaricini_, that from Sweden to Italy, and as well in
England as North America, the same species are to be found. Of 500
_Agaricini_ met with in St. Petersburg, there are only two or three
which have not been discovered in Sweden; and again, of fifty species
known in Greenland, there is not one that is not common in Sweden. The
same remarks hold good in reference to the _Agaricini_ of Siberia,
Kamtschatka, the Ukraine, etc. The countries bordering upon the
Mediterranean possess, however, several peculiar types; and Eastern
and Western Europe present certain dissimilarities in their Agaric
inhabitants. Several species, for example, of _Armillaria_ and
_Tricholoma_, which have been found in Russia, have been met with in
Sweden only in Upland, that is, in the most eastern province; all the
species which belong to the so-called _abiegno-rupestres_ and
_pineto-montanæ_ regions of Sweden are wanting in England; and it is
only in Scotland that the species of northern mountainous and
pine-bearing regions are met with--a circumstance explicable from the
similarity in physical features between Sweden and the northern
portions of Great Britain.

The species of _Coprinus_ appear to find suitable habitats in every
quarter of the globe.

The _Cortinariæ_ predominate in the north; they abound in Northern
latitudes, especially on wooded hills; but the plains offer also some
peculiar species which flourish during the rainy days of August and
September. In less cold countries they are more scarce or entirely
absent. The species of the genus _Hygrophorus_ would at first seem to
have a similar geographical distribution to those of the last group;
but this is really not the case, for the same _Hygrophori_ are to be
found in nearly every country of Europe, and even the hottest
countries (and those under the equator) are not destitute of
representatives of this wide-spread genus.

The _Lactarii_, which are so abundant in the forests of Europe and
North America, appear to grow more and more scarce towards both the
south and north. The same may be stated in regard to _Russula_.

The genus _Marasmius_ is dispersed throughout the globe, and
everywhere presents numerous species. In inter-tropical countries they
are still more abundant, and exhibit peculiarities in growth which
probably might justify their collection into a distinct group.

The genera _Lentinus_ and _Lenzites_ are found in every region of the
world; their principal centre, however, is in hot countries, where
they attain a splendid development. On the contrary, towards the north
they rapidly decrease in number.

The _Polypori_ constitute a group which, unlike that of the Agarics,
especially belongs to hot countries. The _Boleti_ constitute the only
exception to this rule, since they select the temperate and frigid
zones for their special abode, and some of them at times find their
way to the higher regions of the Alps. No one can describe the
luxuriance of the torrid zone in _Polypori_ and _Trametes_, genera of
_Hymenomycetes_, which flourish beneath the shade of the virgin
forests, where perpetual moisture and heat promote their vegetation
and give rise to an infinite variety of forms. But though the genus
_Polyporus_, which rivals _Agaricus_ in the number of its species,
inhabits, in preference, warm climates at large, it nevertheless
exhibits species peculiar to each country. This arises from the
circumstance that the _Polypori_, for the most part, live upon trees,
and are dependent on this or that particular tree for a suitable
habitat; and the tropical flora being prolific in trees of all kinds,
a multitude of the most varied forms of these fungi is a necessary
consequence. _Hexagona_, _Favolus_, and _Laschia_ are common in
inter-tropical countries, but they are either entirely absent or
extremely rare in temperate climes.

When the majority of the species of a genus are of a fleshy
consistence, it may generally be concluded that that genus belongs to
a Northern region, even if it should have some representatives in
lands which enjoy more sunshine. Thus the _Hydna_ are the principal
ornaments of Northern forests, where they attain so luxuriant a growth
and beauty that every other country must yield the palm to Sweden in
respect to them. In an allied genus, that of _Irpex_, the texture
assumes a coriaceous consistence, and we find its species to be more
especially inhabitants of warm climates.

Most of the genera of _Auricularini_ are cosmopolitan, and the same is
true of some species of _Stereum_, of _Corticium_, etc., which are met
with in countries of the most different geographical position. In
tropical countries, these genera of fungi assume the most curious and
luxuriant forms. The single and not considerable genus _Cyphella_
appears to be pretty uniformly distributed over the globe. The
_Clavariæi_ are equally universal in their diffusion, although more
plentiful in the north; however, the genus _Pterula_ possesses several
exotic forms, though in Europe it has but two representative species.
That beautiful genus of _Hymenomycetes_, _Sparassis_, occupies a
similar place next the _Clavariæi_, and is peculiarly a production of
the temperate zone and of the coniferous region.

The fungi which constitute the family of _Tremellini_ prevail in
Europe, Asia, and North America, and exhibit no marked differences
amongst themselves, notwithstanding the distances of the several
countries apart. It must, however, be stated that the _Hirneolæ_ for
the most part inhabit the tropics.

We come now to the _Gasteromycetes_--an interesting family, which
exhibits several ramifications or particular series of developments.
The most perfect _Gasteromycetes_ almost exclusively belong to the
warmer division of the temperate, and to the tropical zone, where
their vegetation is the most luxuriant. Of late the catalogue of these
fungi has been greatly enriched by the addition of numerous genera and
species, proper to hot countries, previously unknown. Not uncommonly,
the exotic floras differ from ours, not merely in respect of the
species, but also of the genera of _Gasteromycetes_. It must, besides,
be observed that this family is rich in well-defined genera, though
very poor in distinct specific forms. Among the genera found in
Europe, many are cosmopolitan.

The _Phalloidei_ present themselves in the torrid zone under the most
varied form and colouring, and comprise many genera rich in species.
In Europe their number is very restricted. As we advance northward
they decrease rapidly, so that the central districts of Sweden possess
only a single species, the _Phallus impudicus_, and even this solitary
representative of the family is very scarce. In Scania, the most
southern province of Sweden, there is likewise but one genus and one
species belonging to it, viz., the _Mutinus caninus_. Among other
members of the _Phalloidei_, may be further mentioned the _Lysurus_ of
China, the _Aseröe_ of Van Diemen's Land, and the _Clathrus_, one
species of which, _C. cancellatus_, has a very wide geographical
range; for instance, it is found in the south of Europe, in Germany,
and in America; it occurs also in the south of England and the Isle of
Wight; whereas the other species of this genus have a very limited
distribution.

The _Tuberacei_[D] are remarkable amongst the fungi in being all of
them more or less hypogeous. They are natives of warm countries, and
are distributed into numerous genera and species. The _Tuberacei_
constitute in Northern latitudes a group of fungi very poor in
specific forms. The few species of the _Hymenogastres_ belonging to
Sweden, with the exception of _Hyperrhiza variegata_ and one example
of the genus _Octaviana_, are confined to the southern provinces. The
greater part of this group, like the _Lycoperdacei_, are met with in
the temperate zone. Most examples of the genus _Lycoperdon_ are
cosmopolitan.

The _Nidulariacei_ and the _Trichodermacei_ appear to be scattered
over the globe in a uniform manner, although their species are not
everywhere similar. The same statement applies to the _Myxogastres_,
which are common in Lapland, and appear to have their central point of
distribution in the countries within the temperate zone. At the same
time, they are not wanting in tropical regions, notwithstanding that
the intensity of heat, by drying up the mucilage which serves as the
medium for the development of their spores, is opposed to their
development.[E]

Of the _Coniomycetes_, the parasitic species, as the _Cæomacei_, the
_Pucciniei_, and the _Ustilagines_, accompany their foster-plants into
almost all regions where they are found; so that smut, rust, and
mildew are as common on wheat and barley in the Himalayas and in New
Zealand as in Europe and America. _Ravenelia_ and _Cronartium_ only
occur in the warmer parts of the temperate zone, whilst _Sartvellia_
is confined to Surinam. Species of _Podisoma_ and _Roestelia_ are as
common in the United States as in Europe, and the latter appears also
at the Cape and Ceylon. Wherever species of _Sphæria_ occur there the
_Sphæronemei_ are found, but they do not appear, according to our
present knowledge, to be so plentiful in tropical as in temperate
countries. The _Torulacei_ and its allies are widely diffused, and
probably occur to a considerable extent in tropical countries.

_Hyphomycetes_ are widely diffused; some species are peculiarly
cosmopolitan, and all seem to be less influenced by climatic
conditions than the more fleshy fungi. The _Sepedoniei_ are
represented by at least one species wherever _Boletus_ is found. The
_Mucedines_ occur everywhere in temperate and tropical regions,
_Penicillium_ and _Aspergillus_ flourishing as much in the latter as
in the former. _Botrytis_ and _Peronospora_ are almost as widely
diffused and as destructive in warmer as in temperate countries, and
although from difficulty in preservation the moulds are seldom
represented to any extent in collections, yet indications of their
presence constantly occur in connection with other forms, to such an
extent as to warrant the conclusion that they are far from uncommon.
The _Dematiei_ are probably equally as widely diffused. Species of
_Helminthosporium_, _Cladosporium_, and _Macrosporium_ seem to be as
common in tropical as temperate climes. The distribution of these
fungi is imperfectly known, except in Europe and North America, but
their occurrence in Ceylon, Cuba, India, and Australasia indicated a
cosmopolitan range. _Cladosporium herbarum_ would seem to occur
everywhere. The _Stilbacei_ and _Isariacei_ are not less widely
diffused, although as yet apparently limited in species. _Isaria_
occurs on insects in Brazil as in North America, and species of
_Stilbum_ and _Isaria_ are by no means rare in Ceylon.

The _Physomycetes_ have representatives in the tropics, species of
_Mucor_ occurring in Cuba, Brazil, and the southern states of North
America, with the same and allied genera in Ceylon. _Antennaria_ and
_Pisomyxa_ seem to reach their highest development in hot countries.

The _Ascomycetes_ are represented everywhere, and although certain
groups are more tropical than others, they are represented in all
collections. The fleshy forms are most prolific in temperate
countries, and only a few species of _Peziza_ affect the tropics, yet
in elevated districts of hot countries, such as the Himalayas of
India, _Peziza_, _Morchella_, and _Geoglossum_ are found. Two or three
species of _Morchella_ are found in Kashmir, and at least one or two
in Java, where they are used as food. The genus _Cyttaria_ is confined
to the southern parts of South America and Tasmania. The United States
equal if they do not exceed European states in the number of species
of the _Discomycetes_. The _Phacidiacei_ are not confined to temperate
regions, but are more rare elsewhere. _Cordierites_ and _Acroseyphus_
(?) are tropical genera, the former extending upwards far into the
temperate zone, as _Hysterium_ and _Rhytisma_ descend into the
tropics. Amongst the _Sphæriacei_, _Xylaria_ and _Hypoxylon_ are well
represented in the tropics, such species as _Xylaria hypoxylon_ and
_Xylaria corniformis_ being widely diffused. In West Africa an
American species of _Hypoxylon_ is amongst the very few specimens that
have ever reached us from the Congo, whilst _H. concentricum_ and
_Ustulina vulgaris_ seem to be almost cosmopolitan. _Torrubia_ and
_Nectria_ extend into the tropics, but are more plentiful in temperate
and sub-tropical countries. _Dothidea_ is well represented in the
tropics, whilst of the species of _Sphæria_ proper, only the more
prominent have probably been secured by collectors; hence the
_Superficiales_ section is better represented than the _Obtectæ_, and
the tropical representatives of foliicolous species are but few.
_Asterina_, _Micropeltis_, and _Pemphidium_ are more sub-tropical than
temperate forms. The _Perisporiacei_ are represented almost
everywhere; although species of _Erysiphe_ are confined to temperate
regions, the genus _Meliola_ occupies its place in warmer climes.
Finally, the _Tuberacei_, which are subterranean in their habits, are
limited in distribution, being confined to the temperate zone, never
extending far into the cold, and but poorly represented out of Europe.
One species of _Mylitta_ occurs in Australia, another in China, and
another in the Neilgherries of India; the genus _Paurocotylis_ is
found in New Zealand and Ceylon. It is said that a species of _Tuber_
is found in Himalayan regions, but in the United States, as well as in
Northern Europe, the _Tuberacei_ are rare.

The imperfect condition of our information concerning very many
countries, even of those partially explored, must render any estimate
or comparison of the floras of those countries most fragmentary and
imperfect. Recently, the mycology of our own islands has been more
closely investigated, and the result of many years' application on the
part of a few individuals has appeared in a record of some 2,809
species,[F] to which subsequent additions have been made, to an extent
of probably not much less than 200 species,[G] which would bring the
total to about 3,000 species. The result is that no material
difference exists between our flora and that of Northern France,
Belgium, and Scandinavia, except that in the latter there are a larger
number of Hymenomycetal forms. The latest estimates of the flora of
Scandinavia are contained in the works of the illustrious Fries,[H]
but these are not sufficiently recent, except so far as regards the
_Hymenomycetes_, for comparison of numbers with British species.

The flora of Belgium has its most recent exponent in the posthumous
work of Jean Kickx; but the 1,370 species enumerated by him can hardly
be supposed to represent the whole of the fungi of Belgium, for in
such case it would be less than half the number found in the British
Islands, although the majority of genera and species are the same.[I]

For the North of France no one could have furnished a more complete
list, especially of the microscopic forms, than M. Desmazières, but we
are left to rely solely upon his papers in "Annales des Sc. Nat." and
his published specimens, which, though by no means representative of
the fleshy fungi, are doubtless tolerably exhaustive of the minute
species. From what we know of French _Hymenomycetes_, their number and
variety appear to be much below those of Great Britain.[J]

The mycologic flora of Switzerland has been very well investigated,
although requiring revision. Less attention having been given to the
minute forms, and more to the _Hymenomycetes_ than in France and
Belgium, may in part account for the larger proportion of the latter
in the Swiss flora.[K]

In Spain and Portugal scarce anything has been done; the small
collection made by Welwitsch can in no way be supposed to represent
the Peninsula.

The fungi of Italy[L] include some species peculiar to the Peninsula.
The _Tuberacei_ are well represented, and although the _Hymenomycetes_
do not equal in number those of Britain or Scandinavia, a good
proportion is maintained.

Bavaria and Austria (including Hungary, and the Tyrol) are being more
thoroughly investigated than hitherto, but the works of Schæffer,
Tratinnick, Corda, and Krombholz have made us acquainted with the
general features of their mycology,[M] to which more recent lists and
catalogues have contributed.[N] The publication of dried specimens has
of late years greatly facilitated acquaintance with the fungi of
different countries in Europe, and those issued by Baron Thümen from
Austria do not differ materially from those of Northern Germany,
although Dr. Rehm has made us acquainted with some new and interesting
forms from Bavaria.[O]

Russia is to a large extent unknown, except in its northern
borders.[P] Karsten has investigated the fungi of Finland,[Q] and
added considerably to the number of _Discomycetes_, for which the
climate seems to be favourable; but, as a whole, it may be concluded
that Western and Northern Europe are much better explored than the
Eastern and South-Eastern, to which we might add the South, if Italy
be excepted.

We have only to add, for Europe, that different portions of the German
empire have been well worked, from the period of Wallroth to the
present.[R] Recently, the valley of the Rhine has been exhaustively
examined by Fuckel;[S] but both Germany and France suffered checks
during the late war which made their mark on the records of science
not so speedily to be effaced. Denmark, with its splendid Flora Danica
still in progress, more than a century after its commencement,[T] has
a mycologic flora very like to that of Scandinavia, which is as well
known.

If we pass from Europe to North America, we find there a mycologic
flora greatly resembling that of Europe, and although Canada and the
extreme North is little known, some parts of the United States have
been investigated. Schweinitz[U] first made known to any extent the
riches of this country, especially Carolina, and in this state the
late Dr. Curtis and H. W. Ravenel continued their labours. With the
exception of Lea's collections in Cincinnati, Wright's in Texas, and
some contributions from Ohio, Alabama, Massachusetts, and New York, a
great portion of this vast country is mycologically unknown. It is
remarkably rich in fleshy fungi, not only in _Agaricini_, but also in
_Discomycetes_, containing a large number of European forms, mostly
European genera, with many species at present peculiar to itself.
Tropical forms extend upwards into the Southern States.

The islands of the West Indies have been more or less examined, but
none so thoroughly as Cuba, at first by Ramon de la Sagra, and
afterwards by Wright.[V] The three principal genera of _Hymenomycetes_
represented are _Agaricus_, _Marasmius_, and _Polyporus_, represented
severally by 82, 51, and 120 species, amounting to more than half the
entire number. Of the 490 species, about 57 per cent. are peculiar to
the island; 13 per cent. are widely dispersed species; 12 per cent.
are common to the island and Central America, together with the warmer
parts of South America and Mexico; 3 per cent. are common to it with
the United States, especially the Southern; while 13 per cent. are
European species, including, however, 13 which may be considered as
cosmopolitan. Some common tropical species do not occur, and, on the
whole, the general character seems sub-tropical rather than tropical.
Many of the species are decidedly those of temperate regions, or at
least nearly allied. Perhaps the most interesting species are those
which occur in the genera _Craterellus_ and _Laschia_, the latter
genus, especially, yielding several new forms. The fact that the
climate is, on the whole, more temperate than that of some other
islands in the same latitudes, would lead us to expect the presence of
a comparatively large number of European species, or those which are
found in the more northern United States, or British North America,
and may account for the fact that so small a proportion of species
should be identical with those from neighbouring islands.

In Central America only a few small collections have been made, which
indicate a sub-tropical region.

From the northern parts of South America, M. Leprieur collected in
French Guiana.[W] Southwards of this, Spruce collected in the
countries bordering on the River Amazon, and Gardner in Brazil,[X]
Gaudichaud in Chili and Peru,[Y] Gay in Chili,[Z] Blanchet in
Bahia,[a] Weddell in Brazil,[b] and Auguste de Saint Hiliare[c] in
the same country. Small collections have also been made in the
extreme south. All these collections contain coriaceous species of
_Polyporus_, _Favolus_, and allied genera, with _Auricularini_,
together with such _Ascomycetes_ as _Xylaria_, and such forms of
_Peziza_ as _P. tricholoma_, _P. Hindsii_, and _P. macrotis_. As
yet we cannot form an estimate of the extent or variety of the
South American flora, which has furnished the interesting genus
_Cyttaria_, and may yet supply forms unrecognized elsewhere.

The island of Juan Fernandez furnished to M. Bertero a good
representative collection,[d] which is remarkable as containing more
than one-half its number of European species, and the rest possessing
rather the character of those of a temperate than a sub-tropical
region.

Australasia has been partly explored, and the results embodied in the
Floras of Dr. Hooker and subsequent communications. In a note to an
enumeration of 235 species in 1872, the writer observes that "many of
them are either identical with European species, or so nearly allied
that with dried specimens only, unaccompanied by notes or drawings, it
is impossible to separate them; others are species which are almost
universally found in tropical or sub-tropical countries, while a few
only are peculiar to Australia, or are undescribed species, mostly of
a tropical type. The collections on the whole can scarcely be said to
be of any great interest, except so far as geographical distribution
is concerned, as the aberrant forms are few."[e]

The fungi collected by the Antarctic Expedition in Auckland and
Campbell's Islands, and in Fuegia and the Falklands,[f] were few and
of but little interest, including such cosmopolitan forms as _Sphæria
herbarum_ and _Cladosporium herbarum_, _Hirneola auricula-judæ_,
_Polyporus versicolor_, _Eurotium herbariorum_, etc.

In New Zealand a large proportion have been found, and these may be
taken to represent the general character of the fungi of the islands,
which is of the type usually found in temperate regions.[g]

The fungi of Asia are so little known that no satisfactory conclusions
can be drawn from our present incomplete knowledge. In India, the
collections made by Dr. Hooker in his progress to the Sikkim
Himalayas,[h] a few species obtained by M. Perottet in Pondicherry,
and small collections from the Neilgherries,[i] are almost all that
have been recorded. From these it may be concluded that elevations
such as approximate a temperate climate are the most productive, and
here European and North American genera, with closely allied species,
have the preponderance. The number of _Agaricini_, for instance, is
large, and amongst the twenty-eight subgenera into which the genus
_Agaricus_ is divided, eight only are unrepresented. Casual specimens
received from other parts of India afford evidence that here is a vast
field unexplored, the forests and mountain slopes of which would
doubtless afford an immense number of new and interesting forms.

Of the Indian Archipelago, Java has been most explored, both by
Junghuhn[j] and Zollinger.[k] The former records 117 species in 40
genera, Nees von Esenbeck and Blume 11 species in 3 genera, and
Zollinger and Moritzi 31 species in 20 genera, making a total of 159
species, of which 47 belong to _Polyporus_. Léveillé added 87
species, making a total of 246 species. The fungi of Sumatra, Borneo,
and other islands are partly the same and partly allied, but of a
similar tropical character.

The fungi of the island of Ceylon, collected by Gardner, Thwaites, and
König, were numerous. The Agarics comprise 302 species, closely
resembling those of our own country.[l] It is singular that every one
of the subgenera of Fries is represented, though the number of species
in one or two is greatly predominant. _Lepiota_ and _Psalliota_ alone
comprise one-third of the species, while _Pholiota_ offers only a
single obscure species. The enumeration recently published of the
succeeding families contains many species of interest.

In Africa, the best explored country is Algeria, although unfortunately
the flora was never completed.[m] The correspondence between the
fungi of Algeria and European countries is very striking, and the
impression is not removed by the presence of a few sub-tropical forms.
It is probable that were the fungi of Spain known the resemblance would
be more complete.

From the Cape of Good Hope and Natal collections have been made by
Zeyher,[n] Drége, and others, and from these we are enabled to form a
tolerable estimate of the mycologic flora. Of the _Hymenomycetes_, the
greater part belong to _Agaricus_: there are but four or five
_Polypori_ in Zeyher's collection, one of which is protean. The
_Gasteromycetes_ are interesting, belonging to many genera, and
presenting two, _Scoleciocarpus_ and _Phellorinia_, which were founded
upon specimens in this collection. _Batarrea_, _Tulostoma_, and
_Mycenastrum_ are represented by European species. There are also two
species of _Lycoperdon_, and one of _Podaxon_. Besides these, there is
the curious _Secotium Gueinzii_. The genus _Geaster_ does not appear
in the collection, nor _Scleroderma_. Altogether the Cape flora is a
peculiar one, and can scarcely be compared with any other.

At the most, only scattered and isolated specimens have been recorded
from Senegal, from Egypt, or from other parts of Africa, so that, with
the above exceptions, the continent may be regarded as unknown.

From this imperfect summary it will be seen that no general scheme of
geographical distribution of fungi can as yet be attempted, and the
most we can hope to do is to compare collection with collection, and
what we know of one country with what we know of another, and note
differences and agreements, so as to estimate the probable character
of the fungi of other countries of which we are still in ignorance. It
is well sometimes that we should attempt a task like the present,
since we then learn how much there is to be known, and how much good
work lies waiting to be done by the capable and willing hands that may
hereafter undertake it.

   [A] Mr. E. P. Fries, in "Ann. des Sci. Nat." 1861, xv. p. 10.

   [B] Berkeley and Broome, "Enumeration of the Fungi of Ceylon," in
       "Journ. Linn. Soc." xiv. Nos. 73, 74, 1873.

   [C] Fries, "On the Geographical Distribution of Fungi," in "Ann. and
       Mag. Nat. Hist." ser. iii. vol. ix. p. 279.

   [D] The _Hypogæi_ are evidently intended here by Fries.

   [E] Fries, "On the Geographical Distribution of Fungi" in "Ann. and
       Mag. Nat. Hist." ser. 3, vol. ix. p. 285.

   [F] Cooke's "Handbook of British Fungi," 2 vols. 1871.

   [G] "Grevillea," vols. i. and ii. London, 1872-1874.

   [H] Fries, "Summa Vegetabilium Scandinaviæ" (1846), and "Monographia
       Hymenomycetum Sueciæ" (1863); "Epicrisis Hymenomycetum Europ."
       (1874).

   [I] "Flore cryptogamique des Flanders" (1867).

   [J] "Ainé Plantes Cryptogames-cellulaires du Départment de Saone et
       Loire" (1863); Bulliard, "Hist. des Champignons de la France"
       (1791); De Candolle, "Flore Française" (1815); Duby, "Botanicon
       Gallicum" (1828-1830); Paulet, "Iconographie des Champignons"
       (1855); Godron, "Catalogue des Plantes Cellulaires du
       Départment de la Meurthe" (1845); Crouan, "Florule du
       Finistëre" (1867); De Seynes, "Essai d'une Flore Mycologique de
       la Région de Montpellier et du Gard" (1863).

   [K] Secretan, "Mycographie Suisse" (1833); Trog, "Verzeichniss
       Schweizerischer Schwämme" (1844).

   [L] Passerini, "Funghi Parmensi," in "Giorn. Bot. Italiano"
       (1872-73); Venturi, "Miceti dell' Agro Bresciano" (1845);
       Viviani, "Funghi d'Italia" (1834); Vittadini, "Funghi
       Mangerecci d'Italia" (1835).

   [M] Schæffer, "Fungorum qui in Bavaria," &c. (1762-1774); Tratinnick,
       "Fungi Austriaci" (1804-1806 and 1809-30); Corda, "Icones
       Fungorum" (Prague, 1837-1842); Krombholz, "Abbildungen der
       Schwämme" (1831-1849).

   [N] Reichardt, "Flora von Iglau;" Niessl, "Cryptogamenflora
       Nieder-Oesterreichs" (1857, 1859); Schulzer, "Schwämme Ungarns,
       Slavoniens," &c.

   [O] Rehm, "Ascomyceten," fasc. i.-iv.

   [P] Weinmann, "Hymeno-et Gasteromycetes," in "Imp. Ross" (1836);
       Weinmann, "Enumeratio Stirpium, in Agro Petropolitano" (1837).

   [Q] Karsten, "Fungi in insulis Spetsbergen collectio" (1872);
       Karsten, "Monographia Pezizarum fennicarum" (1869); Karsten,
       "Symbolæ ad Mycologiam fennicam" (1870).

   [R] Rabenhorst, "Deutschlands Kryptogamen Flora" (1844); Wallroth,
       "Flora Germanica" (1833); Sturm, "Deutschlands Flora, iii. die
       Pilze" (1837, &c.).

   [S] Fuckel, "Symbolæ mycologicæ" (1869).

   [T] "Flora Danica" (1766-1873); Holmskjold, "Beata ruris otia Fungis
       Danicis impensa" (1799); Schumacher, "Enumeratio plantarum
       Sellandiæ" (1801).

   [U] Schweinitz, "Synopsis Fungorum," in "America Boreali," &c.
       (1834). Lea, "Catalogue of Plants of Cincinnati" (1849);
       Curtis, "Catalogue of the Plants of North Carolina" (1867);
       Berkeley, "North American Fungi," in "Grevillea," vols.
       i.-iii.; Peck, in "Reports of New York Museum Nat. Hist."

   [V] Berkeley and Curtis, "Fungi Cubensis," in "Journ. Linn. Soc."
       (1868); Ramon de la Sagra, "Hist. Phys. de l'Isle de Cuba,
       Cryptogames, par Montagne" (1841); Montagne, in "Ann. des Sci.
       Nat." February, 1842.

   [W] Montagne, "Cryptogamia Guyanensis," "Ann. Sci. Nat." 4^me sér.
       iii.

   [X] Berkeley, in "Hooker's Journal of Botany" for 1843, &c.

   [Y] Montagne, in "Ann. des Sci. Nat." 2^me sér. vol. ii. p. 73
       (1834).

   [Z] Gay, "Hist. fisica y politica de Chile" (1845).

   [a] Berkeley and Montagne, "Ann. des Sci. Nat." xi. (April, 1849).

   [b] Montagne, in "Ann. des Sci. Nat." 4^me sér. v. No. 6.

   [c] Montagne, in "Ann. des Sci. Nat." (July, 1839).

   [d] Montagne, "Prodromus Floræ Fernandesianæ," in "Ann. des Sci.
       Nat." (June, 1835).

   [e] Berkeley, "On Australian Fungi," in "Journ. Linn. Society," vol.
       xiii. (May, 1872).

   [f] Hooker's "Cryptogamia Antarctica," pp. 57 and 141.

   [g] Hooker's "New Zealand Flora."

   [h] Berkeley, "Sikkim Himalayan Fungi," in Hooker's "Journal of
       Botany" (1850), p. 42, &c.

   [i] Montagne, "Cryptogamæ Neilgherrensis," in "Ann. des Sci. Nat."
       2^me sér. xviii. p. 21 (1842).

   [j] Junghuhn, "Premissa in Floram Crypt. Javæ."

   [k] Zollinger, "Fungi Archipalegi Malaijo Neerlandici novi."

   [l] Berkeley and Broome, "Fungi of Ceylon," in "Journ. Linn. Soc."
       for May, 1871.

   [m] "Flore d'Algerie, Cryptogames" (1846, &c.).

   [n] Berkeley, in Hooker's "Journal of Botany," vol. ii. (1843), p.
       408.



XIV.

COLLECTION AND PRESERVATION.


The multitudinous forms which fungi assume, the differences of
substance, and variability in size, render a somewhat detailed account
of the modes adopted for their collection and preservation necessary.
The habitats of the various groups have already been indicated, so
that there need be no difficulty in selecting the most suitable spots,
and as to the period of the year, this will be determined by the class
of objects sought. Although it may be said that no time, except when
the ground is covered with snow, is entirely barren of fungi, yet
there are periods more prolific than others.[A] Fleshy fungi, such as
the _Hymenomycetes_, are most common from September until the frosts
set in, whereas many microscopic species may be found in early spring,
and increase in number until the autumn.

The collector may be provided with an ordinary collecting box, but
for the Agarics an open shallow basket is preferable. A great number
of the woody kinds may be carried in the coat-pocket, and foliicolous
species placed between the leaves of a pocket-book. It is a good
plan to be provided with a quantity of soft bibulous paper, in
which specimens can be wrapped when collected, and this will
materially assist in their preservation when transferred to box or
basket. A large clasp-knife, a small pocket-saw, and a pocket-lens
will complete the outfit for ordinary occasions. In order to
preserve the fleshy fungi for the herbarium, there is but one
method, which has often been described. The Agaric, or other
similar fungus, is cut perpendicularly from the pileus downwards
through the stem. A second cut in the same direction removes a thin
slice, which represents a section of the fungus; this may be laid
on blotting paper, or plant-drying paper, and put under slight
pressure to dry. From one-half of the fungus the pileus is removed,
and with a sharp knife the gills and fleshy portion of the pileus
are cut away. In the same manner the inner flesh of the half stem is
also cleared. When dried, the half of the pileus is placed in its
natural position on the top of the half stem, and thus a portrait of
the growing fungus is secured, whilst the section shows the
arrangement of the hymenium and the character of the stem. The
other half of the pileus may be placed, gills downward, on a piece
of black paper, and allowed to rest there during the night. In the
morning the spores will have been thrown down upon the paper,
which may be placed with the other portions. When dry, the section,
profile, and spore paper may be mounted together on a piece of stiff
paper, and the name, locality, and date inscribed below, with any
additional particulars. It is advisable here to caution the collector
never to omit writing down these particulars at once when the
preparations are made, and to place them together, between the
folds of the drying paper, in order to prevent the possibility of a
mistake. Some small species may be dried whole or only cut down the
centre, but the spores should never be forgotten. When dried, either
before or after mounting, the specimens should be poisoned, in
order to preserve them from the attacks of insects. The best medium
for this purpose is carbolic acid, laid on with a small hog-hair
brush. Whatever substance is used, it must not be forgotten by the
manipulator that he is dealing with poison, and must exercise
caution. If the specimens are afterwards found to be insufficiently
poisoned, or that minute insects are present in the herbarium, fresh
poisoning will be necessary. Some think that benzine or spirits of
camphor is sufficient, but as either is volatile, it is not to be
trusted as a permanent preservative. Mr. English, of Epping, by an
ingenious method of his own, preserves a great number of the fleshy
species in their natural position, and although valueless for an
herbarium, they are not only very ornamental, but useful, if space
can be devoted to them.

Leaf parasites, whether on living or dead leaves, may be dried in the
usual way for drying plants, between folds of bibulous paper under
pressure. It may be sometimes necessary with dead leaves to throw them
in water, in order that they may be flattened without breaking, and
then dry them in the same manner as green leaves. All species produced
on a hard matrix, as wood, bark, etc., should have as much as possible
of the matrix pared away, so that the specimens may lie flat in the
herbarium. This is often facilitated in corticolous species by
removing the bark and drying it under pressure.

The dusty _Gasteromycetes_ are troublesome, especially the minute
species, and if mounted openly on paper are soon spoiled. A good plan
is to provide small square or round cardboard boxes, of not more than
a quarter of an inch in depth, and to glue the specimen to the bottom
at once, allowing it to dry in that position before replacing the
cover. The same method should be adopted for many of the moulds, such
as _Polyactis_, etc., which, under any circumstances, are difficult to
preserve.

In collecting moulds, we have found it an excellent plan to go out
provided with small wooden boxes, corked at top and bottom, such as
entomologists use, and some common pins. When a delicate mould is
collected on a decayed Agaric, or any other matrix, after clearing
away with a penknife all unnecessary portions of the matrix, the
specimen may be pinned down to the cork in one of these boxes. Another
method, and one advisable also for the _Myxogastres_, is to carry two
or three pill-boxes, in which, after being wrapped in tissue paper,
the specimen may be placed.

A great difficulty is often experienced with microscopic fungi, such,
for instance, as the _Sphæriacei_, in the necessity, whenever a new
examination is required, to soak the specimen for some hours, and then
transfer the fruit to a slide, before it can be compared with any
newly-found specimen that has to be identified. To avoid this, mounted
specimens ready for the microscope are an acquisition, and may be
secured in the following manner. After the fungus has been soaked in
water, where that is necessary, and the hymenium extracted on the
point of a penknife, let it be transferred to the centre of a clean
glass slide. A drop of glycerine is let fall upon this nucleus, then
the covering glass placed over it. A slight pressure will flatten the
object and expel all the superfluous glycerine around the edges of the
covering glass. A spring clip holds the cover in position, whilst a
camel-hair pencil is used to remove the glycerine which may have been
expelled. This done, the edges of the cover may be fixed to the slide
by painting round with gum-dammar dissolved in benzole. In from twelve
to twenty-four hours the spring clip may be removed, and the mount
placed in the cabinet. Glycerine is, perhaps, the best medium for
mounting the majority of these objects, and when dammar and benzole
are used for fixing, there is no difficulty experienced, as is the
case with Canada balsam, if the superfluous glycerine is not wholly
washed away. Specimens of _Puccinia_ mounted in this way when fresh
gathered, and before any shrivelling had taken place, are as plump and
natural in our cabinet as they were when collected six or seven years
ago.

Moulds are always troublesome to preserve in a herbarium in a state
sufficiently perfect for reference after a few years. We have found it
an excellent method to provide some thin plates of mica, the thinner
the better, of a uniform size, say two inches square, or even less.
Between two of these plates of mica enclose a fragment of the mould,
taking care not to move one plate over the other after the mould is
placed. Fix the plates by a clip, whilst strips of paper are gummed or
pasted over the edges of the mica plates so as to hold them together.
When dry, the clip may be removed, and the name written on the paper.
These mounts may be put each in a small envelope, and fastened down in
the herbarium. Whenever an examination is required, the object, being
already dry-mounted, may at once be placed under the microscope. In
this manner the mode of attachment of the spores can be seen, but if
mounted in fluid they are at once detached; and if the moulds are only
preserved in boxes, in the course of a short time nearly every spore
will have fallen from its support.

Two or three accessories to a good herbarium may be named. For fleshy
fungi, especially Agarics, faithfully coloured drawings, side by side
with the dried specimens, will compensate for loss or change of colour
which most species undergo in the process of drying. For minute
species, camera lucida drawings of the spores, together with their
measurements, will add greatly to the practical value of a collection.
In mounting specimens, whether on leaves, bark, or wood, it will be of
advantage to have one specimen glued down to the paper so as to be
seen at once, and a duplicate loose in a small envelope beside it, so
that the latter may at any time be removed and examined under the
microscope.

In arranging specimens for the herbarium, a diversity of taste and
opinion exists as to the best size for the herbarium paper. It is
generally admitted that a small size is preferable to the large one
usually employed for phanerogamous plants. Probably the size of
foolscap is the most convenient, each sheet being confined to a single
species. In public herbaria, the advantage of a uniform size for all
plants supersedes all other advantages, but in a private herbarium,
consisting entirely of fungi, the smaller size is better.

The microscopic examination of minute species is an absolute necessity
to ensure accurate identification. Little special remark is called for
here, since the methods adopted for other objects will be available.
Specimens which have become dry may be placed in water previous to
examination, a process which will be found essential in such genera as
_Peziza_, _Sphæria_, etc. For moulds, which must be examined as opaque
objects, if all their beauties and peculiarities are to be made out, a
half-inch objective is recommended, with the nozzle bevelled as much
to a point as possible, so that no light be obstructed.[B]

In examining the sporidia of minute _Pezizæ_ and some others, the aid
of some reagent will be found necessary. When the sporidia are very
delicate and hyaline, the septa cannot readily be seen if present; to
aid in the examination, a drop of tincture of iodine will be of
considerable advantage. In many cases sporidia, which are very
indistinct in glycerine, are much more distinct when the fluid is
water.

The following hints to travellers, as regards the collection of fungi,
drawn up some years since by the Rev. M. J. Berkeley, have been widely
circulated, and may be usefully inserted here, though at the risk of
repetition:--

"It is frequently complained that in collections of exotic plants, no
tribe is so much neglected as that of fungi; this arises partly from
the supposed difficulty of preserving good specimens, partly from
their being less generally studied than other vegetable productions.
As, however, in no department of botany, there is a greater
probability of meeting with new forms, and the difficulties, though
confessedly great in one or two genera, are far less than is often
imagined, the following hints are respectfully submitted to such
collectors as may desire to neglect no part of the vegetable kingdom.

"The greater proportion, especially of tropical fungi, are dried,
simply by light pressure, with as much ease as phoenogamous plants;
indeed, a single change of the paper in which they are placed is
generally sufficient, and many, if wrapped up in soft paper when
gathered, and submitted to light pressure, require no further
attention. Such as are of a tough leathery nature, if the paper be
changed a few hours after the specimens have been laid in, preserve
all their characters admirably; and if in the course of a few weeks
there is an opportunity of washing them with a solution of turpentine
and corrosive sublimate, submitting them again to pressure for a few
hours merely to prevent their shrinking, there will be no fear of
their suffering from the attacks of insects.

"Many of the mushroom tribe are so soft and watery that it is very
difficult to make good specimens without a degree of labour which is
quite out of the question with travellers. By changing, however, the
papers in which they are dried two or three times the first day, if
practicable, useful specimens may be prepared, especially if a few
notes be made as to colour, etc. The more important notes are as to
the colour of the stem and pileus, together with any peculiarities of
the surface, _e.g._, whether it be dry, viscid, downy, scaly, etc.,
and whether the flesh of the pileus be thin or otherwise; as to the
stem, whether hollow or solid; as to the gills, whether they are
attached to the stem or free; and especially what is their colour and
that of the spores. It is not in general expedient to preserve
specimens in spirits, except others are dried by pressure, or copious
notes be made; except, indeed, in some fungi of a gelatinous nature,
which can scarcely be dried at all by pressure.

"The large woody fungi, the puff-balls, and a great number of those
which grow on wood, etc., are best preserved, after ascertaining that
they are dry and free from larvæ, by simply wrapping them in paper or
placing them in chip-boxes, taking care that they are so closely
packed as not to rub. As in other tribes of plants, it is very
requisite to have specimens in different stages of growth, and notes
as to precise habitats are always interesting.

"The attention of the traveller can scarcely be directed to any more
interesting branch, or one more likely to produce novelty, than the
puff-ball tribe; and he is particularly requested to collect these in
every stage of growth, especially in the earliest, and, if possible,
to preserve some of the younger specimens in spirits. One or two
species are produced on ant-hills, the knowledge of the early state of
which is very desirable.

"The fungi which grow on leaves in tropical climates are scarcely less
abundant than in our own country, though belonging to a different
type. Many of these must constantly come under the eye of the
collector of phoenogams, and would be most acceptable to the
mycologist. But the attention of the collector should also be directed
to the lichen-like fungi, which are so abundant in some countries on
fallen sticks. Hundreds of species of the utmost interest would reward
active research, and they are amongst the easiest to dry; indeed, in
tropical countries, the greater proportion of the species are easy to
preserve, but they will not strike the eye which is not on the watch
for them. The number of fleshy species is but few, and far less
likely to furnish novelty."

                  *       *       *       *       *

In conclusion, we may urge upon all those who have followed us thus
far to adopt this branch of botany as their speciality. Hitherto
it has been very much neglected, and a wide field is open for
investigation and research. The life-history of the majority of
species has still to be read, and the prospects of new discoveries
for the industrious and persevering student are great. All who have as
yet devoted themselves with assiduity have been in this manner
rewarded. The objects are easily obtainable, and there is a constantly
increasing infatuation in the study. Where so much is unknown, not a
few difficulties have to be encountered, and here the race is not to
the swift so much as to the untiring. May our efforts to supply this
introduction to the study receive their most welcome reward in an
accession to the number of the students and investigators of the
nature, uses, and influences of fungi.

   [A] The genus _Chionyphe_ occurs on granaries under snow, as well as
       in that formidable disease, the Madura fungus-foot. (_See_
       Carter's "Mycetoma.")

   [B] Bubbles of air are often very tiresome in the examination of
       moulds. A little alcohol will remove them.



INDEX.


  _Æcidiacci_, structure of, 41.
  _Æcidium_ and _Puccinia_, 199.
      germination, 141.
  _Agaricini_, habitats of, 233.
      structure of, 17.
  Agaric of the olive, 108.
  Agarics, growth of, 138.
  Algo-lichen hypothesis, 10.
  Alveolate spores, 130.
  Amadou, 103.
  American floras, 281.
      fungi, 281.
  Antheridia, presumed, 171.
  Appearance of new forms, 248.
  Arrangement of families, 80.
  Asci and sporidia, 131.
      in Agarics (?), 23.
      their dehiscence, 59.
  _Ascobolei_, structure of, 56.
  _Ascomycetes_, classification of, 75.
      distribution of, 277.
      habitats of, 241.
      structure of, 55.
  _Aspergillus glaucus_, 187.
  Atmosphere, spores in, 214.

  Barberry cluster-cups, 201.
  Barren cysts of _Lecythea_, 37.
  Basidiospores, 120.
  Beech morels, 101.
  Beefsteak fungus, 96.
  Berberry and mildew, 199.
  _Boletus_, esculent species, 95.
  Books on structure, 63.
  _Bulgaria_, its dualism, 198.
  Bunt and smut, 225.
      spores, germination of, 150.

  _Cæomacei_, structure of, 36.
  Camp measles and fever, 213.
  Caudate sporidia, 134.
  Champignon, fairy-ring, 94.
  Change of colour, 114.
  Chantarelle, the, 93.
  Cholera fungi, 213.
  Ciliated stylospores, 124-6.
  Classification of _Ascomycetes_, 75.
      _Coniomycetes_, 69.
      fungi, 64.
      _Gasteromycetes_, 66.
      _Hymenomycetes_, 65.
      _Hyphomycetes_, 73.
      _Physomycetes_, 74.
      tabular view, 80.
  Collecting fungi, 287.
  Colour and its variation, 117.
  Conditions of growth, 269.
  Conidia of _Erysiphei_, 62.
      _Mucor_, 53.
      _Peziza_, 46.
      _Sphæriæ_, 192.
  _Coniomycetes_, classification of, 69.
  _Coniomycetes_, habitats of, 38.
  Conjugating cells, 165.
  Conjugation in _Peronospora_, 171.
      _Peziza_, 175.
  Copulation in _Discomycetes_, 173.
      fungi, 163.
  Corn, mildew, and rust, 224.
  _Cortinarius_, species of, 91.
  Cotton plant diseases, 228.
  Cultivation of fungi, 253.
      _Sclerotia_, 261.
      truffles, 258.
  Currant twig fungus, 193.
  Cystidia, 21.

  _Dacrymyces_, germination of, 140.
  De Bary, on conditions of study, 183.
  Decay rapid, 9.
  Dehiscence of asci, 58.
  Dimorphism in moulds, 187.
      of _Mucor_, 53.
  Disappearance of species, 268.
  _Discomycetes_, 56.
  Dissemination of spores, 119.
  Distribution, geographical, 266.
  Dried fungi, esculent, 87, 94.
  Drying of fungi, 289.
  Dry rot, 223.
  Dualism in _Melanconis_, 197.
      _Podisoma_, 203.
      _Polyactes_, 45.
      _Uredines_, 185.

  Edible fungi in America, 88.
  Ergotized grass, 217.
  _Erysiphe_, conjugation, 176.
  _Erysiphei_, polymorphism, 191.
  Esculent fungi, 82.
  European floras, 279.
  Examination of fungi, 289.
  Exotic floras, 280-5.

  False truffles, 98.
  Fairy-ring champignon, 94.
  Families and orders, table of, 80.
  Fenestrate sporidia, 135.
  Fetid fungi, 116.
  _Fistulina hepatica_, 96.
  Floras of Europe, &c., 279.
  Fly Agaric, 210.
  Food, fungi as, 81.
  Forestry and its foes, 229.
  Fungi collecting abroad, 292.
      in disease, 215.
             mines, 111.
      of America, 281.
             Asia, 284.
      parasitic on animals, 246.
             each other, 244.
      true plants, 5.

  Garden pests, 230.
  _Gasteromycetes_, classification of, 66.
  Geographical distribution, 266.
  Germinating pseudospores, 144.
  Germination of fungi, 137.
      _Mucor_, 157, 164.
      _Podisoma_, 147.
  Gonosphere, in _Peronospora_, 171.
  Growth of Agarics, 138.

  Habitats of fungi, 233.
  Helicoid spores, 129.
  Herbarium for fungi, 291.
  Hints for travellers, 292.
  Hollyhock disease, 230.
  House-fly fungus, 219.
  _Hydnum gelatinosum_, 24.
  Hymenium of fungi, 18.
  _Hymenomycetes_, classification of, 65.
  _Hyphomycetes_, classification of, 73.
      habitats of, 240.
      structure of, 42.
  _Hypogæi_, structure of, 29.

  Influences of fungi, 209.
  Influence on lower animals, 217.
      man, 209.
  Influence on vegetation, 222.
      of woods, 271.
  Injurious moulds, 230, 240.
  Insect, parasites on, 7, 218.
      fungi, 7, 218, 246.
  _Isaria_ and _Torrubia_, 205.

  Ketchup, or catchup, 89.

  Lactescent fungi, 115.
  Lichen-gonidia question, 10.
  Lichens and fungi, 9.
  Little man's bread, 102.
  Luminous Agarics, 105.
      wood, 113.

  Meadow mushroom, 83.
  Medicinal fungi, 102.
  _Melanconiei_, structure of, 35.
  Microscopical mounting, 290.
  Mildew in corn, 199.
  Milky fungi, 92.
      juice, 115.
  Morels, 99, 159.
      germination of, 159.
  Mould cultivation, 263.
  Moulds, and dimorphism, 187.
      structure of, 43.
      to preserve, 290.
  _Mucedines_, habitats of, 240.
      structure of, 44.
  _Mucor_, dualism of, 205.
      growth of, 157.
      structure of, 50.
  Mushroom, analysis of, 19.
      caves of Paris, 255.
      cultivation, 254.
      spawn, 256.
      the edible, 83.
  _Myxogastres_, habitats of, 237.
      structure of, 31.

  Nature of fungi, 1.
  New forms, appearance of, 248.
  _Nidulariacei_, structure of, 34.

  Oak truffles, 260.
  Odours of fungi, 116.
  _Oidium_ and _Erysiphe_, 191.
  Oocysts in _Erysiphe_, 176.
  Oogonia, 136, 169.
      of _Saprolegniæ_, 169.
  Orders and families, table of, 80.
  Oyster mushroom, 86.

  Paper moulds, 248.
  Paraphyses and asci, 49.
  Parasites on plants, 238.
  _Perisporiacei_, structure of, 62.
  _Peronospora_, growth of, 152.
  Pests of forest trees, 229.
      the garden, 230.
  _Peziza_, conidia of, 46.
      _Fuckeliana_, 48.
  _Pezizæ_, their habitats, 242.
  _Phalloidei_, structure of, 28.
  Phenomena of fungi, 105.
  Phosphorescence, 105.
  _Physomycetes_, classification of, 74.
      habitats of, 241.
      structure of, 50.
  _Podaxinei_, structure of, 29.
  _Podisoma_, and its allies, 40, 72.
      and _Roestelia_, 203.
      germination of, 147.
  Poisonous fungi, 209.
  Polymorphism, 182.
  Polymorphy in _Erysiphe_, 191.
  Polyporei, structure of, 23.
  _Polyporus_, edible species, 96.
  Potato disease, 225.
      mould, germination, 155.
  Preservation of fungi, 288.
  Pseudospores, 126.
  _Puccinia_ and _Æcidium_, 199.
  _Puccinia_, germination of, 145.
  _Pucciniæi_, structure of, 38.
  Puff-balls, edible, 98.
  Puff-balls, structure of, 29.
      spores, 123.
  Pycnidia, 62, 180.
      and spermatia, 62.

  _Roestelia_ and _Podisoma_, 203.
  Red rust and cattle food, 217.
  Reproduction, sexual, 163.
  _Rhizomorphæ_, 111.
  _Russula_, edible species of, 93.

  St. George's mushroom, 85.
  _Saprolegnei_, conjugation of, 168.
  _Sclerotia_, 47, 261.
      cultivation, 261.
  Scolecite in _Peziza_, &c., 173.
  Septate stylospores, 124.
  Sexual reproduction, 163.
  Silkworm disease, 220.
  Skin diseases and fungi, 212.
  Slides for the microscope, 290.
  Spawn of fungi, 256.
  Special cultivation, 264.
  Species determinate, 5.
  Spermatia, 128, 179.
      of _Roestelia_, 42.
      in _Tremella_, 26.
  Spermogonia, 178.
  _Sphæria_, sporidia of, 133.
  _Sphæriacei_, structure of, 61.
  _Sphæriæ_, polymorphy, 192.
  _Sphæronemei_, structure of, 35.
  Spiral threads, 32.
  Spontaneous generation, 3.
  Sporangia, 51, 129.
      of _Mucor_, 51.
  Spores in chaplets, 143.
      of _Agaricini_, 121.
             _Gasteromycetes_, 122.
             truffles, 130.
      stellate and crested, 36.
      their dissemination, 119.
  Sporidia, germination of, 160.
      of _Ascomycetes_, 130.
  _Sporidiifera_, structure of, 50
  _Sporifera_ and _Sporidiifera_, 64.
  Star-spored fungus, 125.
  Structure of fungi, 17.
             _Agaricini_, 17.
      books written upon, 63.
      of _Æcidiacei_, 41.
             _Ascomycetes_, 55.
             _Cæomacei_, 36.
             _Hyphomycetes_, 42.
             _Hypogæi_, 29.
             _Melanconiei_, 35.
             _Mucedines_, 44.
             _Mucor_, 50.
             _Myxogastres_, 31.
             _Nidulariacei_, 34.
             _Perisporiacei_, 62.
             _Phalloidei_, 28.
             _Physomycetes_, 50.
             _Podaxinei_, 29.
             _Polyporei_, 23.
             _Pucciniæi_, 38.
             _Sphæriacei_, 61.
             _Sphæronemei_, 35.
             _Torulacei_, 36.
             _Tremellini_, 25.
             _Trichogastres_, 29.
             truffles, 55.
             _Ustilaginei_, 40.
  Study of development, 183.
  Stylospores, 123.
  Subterranean puff-balls, 29.
  Summer and winter spores, 37.
  Supposed animal nature, 2.

  Table of classification, 80.
  Thecaspores, 13
  _Torrubia_ and _Isaria_, 205.
  _Torulacei_, structure of, 36.
  Travellers, hints for, 292.
  _Tremella_, germination of, 139.
  _Tremellini_, structure of, 24.
  _Trichogastres_, habitats of, 237.
      structure of, 29.
  Trichospores, 128.
  Tropical fungi, 272.
  Truffle cultivation, 258.
  Truffles, 55, 101, 258.
      structure of, 55.
  _Tuberacei_, structure of, 55.
  _Tubercularia_ and _Nectria_, 194.

  _Uredines_, germination of, 143.
      polymorphy of, 186.
      structure of, 37.
  Uses of fungi, 82.
  _Ustilaginei_, structure of, 40.
      germination of, 149.

  "Vegetable wasp," 218.
  Vegetative and reproductive system, 7.
  Viennese fungi, 84.
  Vine and hop disease, 227.

  White rust germination, 151.
  Winter and summer spores, 37.

  Zones of distribution, 270.
  Zoospores of _Cystopus_, 38.
      white rust, 151.
  Zygospores of _Mucor_, 158, 164.



_International Scientific Series._


D. APPLETON & CO. have the pleasure of announcing that they have made
arrangements for publishing, and have recently commenced the issue of,
a SERIES OF POPULAR MONOGRAPHS, or small works, under the above title,
which will embody the results of recent inquiry in the most
interesting departments of advancing science.

The character and scope of this series will be best indicated by a
reference to the names and subjects included in the subjoined list,
from which it will be seen that the coöperation of the most
distinguished professors in England, Germany, France, and the
United States, has been secured, and negotiations are pending for
contributions from other eminent scientific writers.

The works will be issued in New York, London, Paris, Leipsic, Milan,
and St. Petersburg.

The INTERNATIONAL SCIENTIFIC SERIES is entirely an American project,
and was originated and organized by Dr. E. L. Youmans, who spent the
greater part of a year in Europe, arranging with authors and
publishers. The forthcoming volumes are as follows:

  Prof. LOMMEL (University of Erlangen), _Optics._ (In press.)

  Rev. M. J. BERKELEY, M.A., F.L.S., and M. COOKE, M.A., LL. D.,
    _Fungi; their Nature, Influences, and Uses._ (In press.)

  Prof. W. KINGDON CLIFFORD, M.A., _The First Principles of the Exact
    Sciences explained to the non-mathematical._

  Prof. T. H. HUXLEY, LL. D., F.R.S., _Bodily Motion and Consciousness._

  Dr. W. B. CARPENTER, LL. D., F.R.S., _The Physical Geography of the
    Sea._

  Prof. WILLIAM ODLONG, F.R.S., _The Old Chemistry viewed from the New
    Standpoint._

  W. LAUDER LINDSAY, M.D., F.R.S.E., _Mind in the Lower Animals._

  Sir JOHN LUBBOCK, Bart, F.R.S., _The Antiquity of Man._

  Prof. W. T. THISELTON DYER, B.A., B. Sc., _Form and Habit in
    Flowering Plants._

  Mr. J. N. LOCKYER, F.R.S., _Spectrum Analysis._

  Prof. MICHAEL FOSTER, M.D., _Protoplasm and the Cell Theory._

  Prof. W. STANLEY JEVONS, _Money: and the Mechanism of Exchange._

  H. CHARLTON BASTIAN, M.D., F.R.S., _The Brain as an Organ of Mind._

  Prof. A. C. RAMSAY, LL. D., F.R.S., _Earth Sculpture: Hills,
    Valleys, Mountains, Plains, Rivers, Lakes; how they were produced,
    and how they have been destroyed._

  Prof. RUDOLPH VIRCHOW (Berlin University), _Morbid Physiological
    Action._

  Prof. CLAUDE BERNARD, _Physical and Metaphysical Phenomena of
    life._

  Prof. H. SAINTE-CLAIRE DEVILLE, _An Introduction to General
    Chemistry._

  Prof. WURTZ, _Atoms and the Atomic Theory._

  Prof. DE QUATREFAGES, _The Negro Races._

  Prof. LACAZE-DUTHIERS, _Zoology since Cuvier._

  Prof. BERTHELOT, _Chemical Synthesis._

  Prof. J. ROSENTHAL, _General Physiology of Muscles and Nerves._

  Prof. JAMES D. DANA, M.A., LL. D., _On Cephalization; or,
    Head-Characters in the Gradation and Progress of Life._

  Prof. S. W. JOHNSON, M.A., _On the Nutrition of Plants._

  Prof. AUSTIN FLINT, Jr., M.D., _The Nervous System and its Relation
    to the Bodily Functions._

  Prof. W. D. WHITNEY, _Modern Linguistic Science._

  Prof. C. A. YOUNG, Ph. D. (of Dartmouth College), _The Sun._

  Prof. BERNSTEIN (University of Halle), _Physiology of the Senses._

  Prof. FERDINAND COHN (Breslau University), _Thallophytes (Algæe,
    Lichens, Fungi)._

  Prof. HERMANN (University of Zurich), _Respiration._

  Prof. LEUCKART (University of Leipsic), _Outlines of Animal
    Organization._

  Prof. LIEBREICH (University of Berlin), _Outlines of Toxicology._

  Prof. KUNDT (University of Strasburg), _On Sound._

  Prof. REES (University of Erlangen), _On Parasitic Plants._

  Prof. STEINTHAL (University of Berlin), _Outlines of the Science of
    Language._

  E. ALGLAVE (Professor of Constitutional and Administrative Law at
    Douai, and of Political Economy at Lille), _The Primitive Elements
    of Political Constitutions._

  P. LORAIN (Professor of Medicine, Paris), _Modern Epidemics._

  Prof. SCHÜTZENBERGER (Director of the Chemical Laboratory at the
    Sorbonne), _On Fermentations._

  Mons. DEBRAY, _Precious Metals._



_Opinions of the Press on the "International Scientific Series."_


I.

Tyndall's Forms of Water.

 1 vol., 12mo.            Cloth. Illustrated              Price, $1.50.

"In the volume now published, Professor Tyndall has presented a noble
illustration of the acuteness and subtlety of his intellectual powers,
the scope and insight of his scientific vision, his singular command
of the appropriate language of exposition, and the peculiar vivacity
and grace with which he unfolds the results of intricate scientific
research."--_N. Y. Tribune_.

"The 'Forms of Water,' by Professor Tyndall, is an interesting and
instructive little volume, admirably printed and illustrated. Prepared
expressly for this series, it is in some measure a guarantee of the
excellence of the volumes that will follow, and an indication that the
publishers will spare no pains to include in the series the freshest
investigations of the best scientific minds."--_Boston Journal_.

"This series is admirably commenced by this little volume from the pen
of Prof. Tyndall. A perfect master of his subject, he presents in a
style easy and attractive his methods of investigation, and the
results obtained, and gives to the reader a clear conception of all the
wondrous transformations to which water is subjected."--_Churchman_.


II.

Bagehot's Physics and Politics.

 1 vol., 12mo.                                           Price, $1.50.

"If the 'International Scientific Series' proceeds as it has begun, it
will more than fulfil the promise given to the reading public in its
prospectus. The first volume, by Professor Tyndall, was a model of
lucid and attractive scientific exposition; and now we have a second,
by Mr. Walter Bagehot, which is not only very lucid and charming, but
also original and suggestive in the highest degree. Nowhere since the
publication of Sir Henry Maine's 'Ancient Law,' have we seen so many
fruitful thoughts suggested in the course of a couple of hundred
pages.... To do justice to Mr. Bagehot's fertile book, would require a
long article. With the best of intentions, we are conscious of having
given but a sorry account of it in these brief paragraphs. But we hope
we have said enough to commend it to the attention of the thoughtful
reader."--Prof. JOHN FISKE, in the _Atlantic Monthly_.

"Mr. Bagehot's style is clear and vigorous. We refrain from
giving a fuller account of these suggestive essays, only because we
are sure that our readers will find it worth their while to
peruse the book for themselves; and we sincerely hope that the
forthcoming parts of the 'International Scientific Series' will be
as interesting."--_Athenæum_.

"Mr. Bagehot discusses an immense variety of topics connected with the
progress of societies and nations, and the development of their
distinctive peculiarities; and his book shows an abundance of
ingenious and original thought."--ALFRED RUSSELL WALLACE, in
_Nature_.


III.

Foods.

By Dr. EDWARD SMITH.

 1 vol., 12mo.  Cloth Illustrated.                     Price, $1.75.

In making up THE INTERNATIONAL SCIENTIFIC SERIES, Dr Edward Smith was
selected as the ablest man in England to treat the important subject
of Foods. His services were secured for the undertaking, and the
little treatise he has produced shows that the choice of a writer on
this subject was most fortunate, as the book is unquestionably the
clearest and best-digested compend of the Science of Foods that has
appeared in our language.

  "The book contains a series of diagrams, displaying the effects
  of sleep and meals on pulsation and respiration, and of various
  kinds of food on respiration, which, as the results of Dr
  Smith's own experiments, possess a very high value. We have
  not far to go in this work for occasions of favorable criticism;
  they occur throughout, but are perhaps most apparent in those
  parts of the subject with which Dr. Smith's name is especially
  linked."--_London Examiner._

  "The union of scientific and popular treatment in the composition
  of this work will afford an attraction to many readers who would
  have been indifferent to purely theoretical details.... Still his
  work abounds in information, much of which is of great value, and
  a part of which could not easily be obtained from other sources.
  Its interest is decidedly enhanced for students who demand both
  clearness and exactness of statement, by the profusion of well
  executed woodcuts, diagrams, and tables, which accompany the
  volume.... The suggestions of the author on the use of tea and
  coffee, and of the various forms of alcohol, although perhaps not
  strictly of a novel character, are highly instructive, and form an
  interesting portion of the volume."--_N. Y. Tribune._


IV.

Body and Mind.

THE THEORIES OF THEIR RELATION.

By ALEXANDER BAIN, LL.D.

 1 vol.,   12mo. Cloth                                  Price, $1.50.

PROFESSOR BAIN is the author of two well-known standard works upon the
Science of Mind--"The Senses and the Intellect," and "The Emotions and
the Will." He is one of the highest living authorities in the school
which holds that there can be no sound or valid psychology unless the
mind and the body are studied, as they exist, together.

  "It contains a forcible statement of the connection between
  mind and body, studying their subtile interworkings by the
  light of the most recent physiological investigations. The
  summary in Chapter V., of the investigations of Dr. Lionel Beale
  of the embodiment of the intellectual functions in the cerebral
  system, will be found the freshest and most interesting part of
  his book. Prof. Bain's own theory of the connection between the
  mental and the bodily part in man is stated by himself to be as
  follows: There is 'one substance, with two sets of properties,
  two sides, the physical and the mental--a _double-faced unity_.'
  While, in the strongest manner, asserting the union of mind
  with brain, he yet denies 'the association of union _in place_,'
  but asserts the union of close succession in time,' holding that
  'the same being is, by alternate fits, under extended and under
  unextended consciousness.'"--_Christian Register._


V.

The Study of Sociology.

By HERBERT SPENCER.

 1 vol.,      12mo. Cloth                            Price, $1.50.

  "The philosopher whose distinguished name gives weight and
  influence to this volume, has given in its pages some of the
  finest specimens of reasoning in all its forms and departments.
  There is a fascination in his array of facts, incidents, and
  opinions, which draws on the reader to ascertain his conclusions.
  The coolness and calmness of his treatment of acknowledged
  difficulties and grave objections to his theories win for him a
  close attention and sustained effort, on the part of the reader,
  to comprehend, follow, grasp, and appropriate his principles. This
  book, independently of its bearing upon sociology, is valuable as
  lucidly showing what those essential characteristics are which
  entitle any arrangement and connection of facts and deductions to
  be called a _science_."--_Episcopalian._

  "This work compels admiration by the evidence which it gives of
  immense research, study, and observation, and is, withal, written
  in a popular and very pleasing style. It is a fascinating work, as
  well as one of deep practical thought."--_Bost. Post._

  "Herbert Spencer is unquestionably the foremost living thinker in
  the psychological and sociological fields, and this volume is an
  important contribution to the science of which it treats.... It
  will prove more popular than any of its author's other creations,
  for it is more plainly addressed to the people and has a more
  practical and less speculative cast. It will require thought, but
  it is well worth thinking about."--_Albany Evening Journal_.


VI.

The New Chemistry.

By JOSIAH P. COOKE, Jr.,

Erving Professor of Chemistry and Mineralogy in Harvard University.

 1 vol.,      12mo. Cloth                            Price, $2.00.

  "The book of Prof. Cooke is a model of the modern popular science
  work. It has just the due proportion of fact, philosophy, and true
  romance, to make it a fascinating companion, either for the voyage
  or the study."--_Daily Graphic._

  "This admirable monograph, by the distinguished Erving Professor
  of Chemistry in Harvard University, is the first American
  contribution to 'The International Scientific Series,' and a more
  attractive piece of work in the way of popular exposition upon a
  difficult subject has not appeared in a long time. It not only
  well sustains the character of the volumes with which it is
  associated, but its reproduction in European countries will be an
  honor to American science."--_New York Tribune._

  "All the chemists in the country will enjoy its perusal, and many
  will seize upon it as a thing longed for. For, to those advanced
  students who have kept well abreast of the chemical tide, it
  offers a calm philosophy. To those others, youngest of the class,
  who have emerged from the schools since new methods have
  prevailed, it presents a generalization, drawing to its use all
  the data, the relations of which the newly-fledged fact-seeker may
  but dimly perceive without its aid.... To the old chemists, Prof.
  Cooke's treatise is like a message from beyond the mountain. They
  have heard of changes in the science; the clash of the battle of
  old and new theories has stirred them from afar. The tidings, too,
  had come that the old had given way; and little more than this
  they knew.... Prof. Cooke's 'New Chemistry' must do wide service
  in bringing to close sight the little known and the longed for....
  As a philosophy it is elementary, but, as a book of science,
  ordinary readers will find it sufficiently advanced."--_Utica
  Morning Herald._


VII.

The Conservation of Energy.

By BALFOUR STEWART, LL. D., F.R.S.

_With an Appendix treating of the Vital and Mental Applications of the
Doctrine._

 1 vol.,     12mo. Cloth.                               Price, $1.50.

"The author has succeeded in presenting the facts in a clear and
satisfactory manner, using simple language and copious illustration in
the presentation of facts and principles, confining himself, however,
to the physical aspect of the subject. In the Appendix the operation
of the principles in the spheres of life and mind is supplied by the
essays of Professors Le Conte and Bain."--_Ohio Farmer._

"Prof Stewart is one of the best known teachers in Owens College in
Manchester.

"The volume of THE INTERNATIONAL SCIENTIFIC SERIES now before us is an
excellent illustration of the true method of teaching, and will well
compare with Prof. Tyndall's charming little book in the same series
on 'Forms of Water,' with illustrations enough to make clear, but not
to conceal his thoughts, in a style simple and brief."--_Christian
Register, Boston_.

"The writer has wonderful ability to compress much information into a
few words. It is a rich treat to read such a book as this, when there
is so much beauty and force combined with such simplicity."--_Eastern
Press._


VIII.

Animal Locomotion;

Or, WALKING, SWIMMING, AND FLYING.

_With a Dissertation on Aëronautics._

By J. BELL PETTIGREW, M.D., F.R.S., F.R.S.E., F.R.C.P.E.

 1 vol., 12mo.                                          Price, $1.75.

"This work is more than a contribution to the stock of entertaining
knowledge, though, if it only pleased, that would be sufficient excuse
for its publication. But Dr. Pettigrew has given his time to these
investigations with the ultimate purpose of solving the difficult
problem of Aëronautics. To this he devotes the last fifty pages of his
book. Dr. Pettigrew is confident that man will yet conquer the domain
of the air."--_N. Y. Journal of Commerce._

"Most persons claim to know how to walk, but few could explain the
mechanical principles involved in this most ordinary transaction, and
will be surprised that the movements of bipeds and quadrupeds, the
darting and rushing motion of fish, and the erratic flight of the
denizens of the air, are not only analogous, but can be reduced to
similar formula. The work is profusely illustrated, and, without
reference to the theory it is designed to expound, will be regarded as
a valuable addition to natural history."--_Omaha Republic._


IX.

Responsibility in Mental Disease.

By HENRY MAUDSLEY, M.D.,

Fellow of the Royal College of Physicians; Professor of Medical
Jurisprudence in University College, London.

 1 vol., 12mo.    Cloth.                                Price, $1.50.

"Having lectured in a medical college on Mental Disease, this book has
been a feast to us. It handles a great subject in a masterly manner,
and, in our judgment, the positions taken by the author are correct
and well sustained."--_Pastor and People._

"The author is at home in his subject, and presents his views in an
almost singularly clear and satisfactory manner.... The volume is a
valuable contribution to one of the most difficult, and at the same
time one of the most important subjects of investigation at the
present day."--_N. Y. Observer._

"It is a work profound and searching, and abounds in wisdom."--_Pittsburg
Commercial._

"Handles the important topic with masterly power, and its suggestions
are practical and of great value."--_Providence Press._


X.

The Science of Law.

By SHELDON AMOS, M.A.,

Professor of Jurisprudence in University College, London; author of "A
Systematic View of the Science of Jurisprudence," "An English Code,
its Difficulties and the Modes of overcoming them," etc., etc.

 1 vol.,   12mo. Cloth.                                   Price, $1.75.

"The valuable series of 'International Scientific' works, prepared by
eminent specialists, with the intention of popularizing information in
their several branches of knowledge, has received a good accession in
this compact and thoughtful volume. It is a difficult task to give the
outlines of a complete theory of law in a portable volume, which he
who runs may read, and probably Professor Amos himself would be the
last to claim that he has perfectly succeeded in doing this. But he
has certainly done much to clear the science of law from the technical
obscurities which darken it to minds which have had no legal training,
and to make clear to his 'lay' readers in how true and high a sense it
can assert its right to be considered a science, and not a mere
practice."--_The Christian Register._

"The works of Bentham and Austin are abstruse and philosophical,
and Maine's require hard study and a certain amount of special
training. The writers also pursue different lines of investigation,
and can only be regarded as comprehensive in the departments they
confined themselves to. It was left to Amos to gather up the result
and present the science in its fullness. The unquestionable merits of
this, his last book, are, that it contains a complete treatment of
a subject which has hitherto been handled by specialists, and it
opens up that subject to every inquiring mind.... To do justice to
'The Science of Law' would require a longer review than we have
space for. We have read no more interesting and instructive book for
some time. Its themes concern every one who renders obedience to laws,
and who would have those laws the best possible. The tide of legal
reform which set in fifty years ago has to sweep yet higher if the
flaws in our jurisprudence are to be removed. The process of change
cannot be better guided than by a well-informed public mind, and
Prof. Amos has done great service in materially helping to promote
this end."--_Buffalo Courier._


XI.

Animal Mechanism,

_A Treatise on Terrestrial and Aërial Locomotion._

By E. J. MAREY,

Professor at the College of France, and Member of the Academy of
Medicine.

With 117 Illustrations, drawn and engraved under the direction of the
author.

 1 vol.,    12mo. Cloth.                                 Price, $1.75

"We hope that, in the short glance which we have taken of some of the
most important points discussed in the work before us, we have
succeeded in interesting our readers sufficiently in its contents to
make them curious to learn more of its subject-matter. We cordially
recommend it to their attention.

"The author of the present work, it is well known, stands at the head
of those physiologists who have investigated the mechanism of animal
dynamics--indeed, we may almost say that he has made the subject his
own. By the originality of his conceptions, the ingenuity of his
constructions, the skill of his analysis, and the perseverance of his
investigations, he has surpassed all others in the power of unveiling
the complex and intricate movements of animated beings."--_Popular
Science Monthly._


XII.

History of the Conflict between Religion and Science.

By JOHN WILLIAM DRAPER, M.D., LL. D.,

Author of "The Intellectual Development of Europe."

 1 vol.,     12mo.                                       Price, $1.75.

"This little 'History' would have been a valuable contribution to
literature at any time, and is, in fact, an admirable text-book upon a
subject that is at present engrossing the attention of a large number
of the most serious-minded people, and it is no small compliment to
the sagacity of its distinguished author that he has so well gauged
the requirements of the times, and so adequately met them by the
preparation of this volume. It remains to be added that, while the
writer has flinched from no responsibility in his statements, and has
written with entire fidelity to the demands of truth and justice,
there is not a word in his book that can give offense to candid and
fair-minded readers."--_N. Y. Evening Post._

"The key-note to this volume is found in the antagonism between the
progressive tendencies of the human mind and the pretensions of
ecclesiastical authority, as developed in the history of modern
science. No previous writer has treated the subject from this point of
view, and the present monograph will be found to possess no less
originality of conception than vigor of reasoning and wealth of
erudition.... The method of Dr. Draper, in his treatment of the
various questions that come up for discussion, is marked by singular
impartiality as well as consummate ability. Throughout his work he
maintains the position of an historian, not of an advocate. His tone
is tranquil and serene, as becomes the search after truth, with no
trace of the impassioned ardor of controversy. He endeavors so far to
identify himself with the contending parties as to gain a clear
comprehension of their motives, but, at the same time, he submits
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Transcriber's Notes

A few words are variably hyphenated. They are unchanged from the
original. They include uredospores, subglobose, and puffballs.

Page 23 footnote K:
  a genus of parasitic Sph[oe]riaceous fungi.
  changed to
  a genus of parasitic Sphæriaceous fungi.

Page 29
HYPOG[OE]I.--These are subterranean
and
The hypog[oe]ous fungi are curiously connected
Changed [oe] to æ to match others in text.

Page 95
  informs us that he has eaten _Boletus lurdius_
  changed to
  informs us that he has eaten _Boletus luridus_

Page 188
  separate themselves by a partion from the sterigma
  changed to
  separate themselves by a partition from the sterigma

Page 205
  like relations to other sph[oe]riaceous fungi.
  changed to
  like relations to other sphæriaceous fungi.

Page 284
  including such cosmopolitan forms as _Sphæria hebarum_
  changed to
  including such cosmopolitan forms as _Sphæria herbarum_

Page 284
  _Hirneola auricula-judaæ_
  changed to
  _Hirneola auricula-judæ_





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