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Title: How to Know the Ferns
Author: Bastin, S. Leonard
Language: English
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*** Start of this LibraryBlog Digital Book "How to Know the Ferns" ***
HOW TO KNOW
THE FERNS
BY
S. LEONARD BASTIN
WITH THIRTY-THREE ILLUSTRATIONS
METHUEN & CO. LTD.
36 ESSEX STREET W.C.
LONDON
_First Published in 1917_
CONTENTS
CHAP. PAGE
I. The Ferns and their Allies 1
II. Life Histories 13
III. Yesterday and To-day 23
IV. Three Dainty Ferns 33
V. The Bracken Fern and Two Interesting Species 38
VI. The Male Fern and its Relatives 46
VII. The Lady Fern and the Spleenworts 66
VIII. The Polypodies 86
IX. The Royal Fern 93
X. Four Curious Ferns 96
XI. The Club Mosses 101
XII. The Horsetails 112
XIII. Fern Collecting and Preserving 122
XIV. The Culture of Ferns 129
Index 133
LIST OF ILLUSTRATIONS
PAGE
The Bristle Fern 34
The Tunbridge Filmy Fern 36
The Bracken Fern 39
The Maidenhair Fern 42
The Maidenhair Fern (Enlarged view of Back of Frond) 43
The Male Fern 47
The Mountain Buckler Fern 51
The Mountain Buckler Fern (Enlarged) 52
_Nephrodium dilatatum_ 54
The Holly Fern 58
The Oblong Woodsia 62
The Brittle Bladder Fern 64
_Athyrium filix-fæmina_ 67
The Rue-leaved Spleenwort 71
The Rue-leaved Spleenwort (Enlarged Back of Frond) 72
The Sea Spleenwort 76
The Maidenhair Spleenwort 79
The Green Spleenwort 81
The Hartstongue 82
The Sori on the Back of a Hartstongue Frond 83
The Common Polypody 87
Enlargement of the Sori on the Frond of Common Polypody 88
The Beech Fern 89
The Royal Fern 94
The Adder’s Tongue 97
The Moonwort 99
The Common Club Moss 102
The Fir Club Moss 104
The Quillwort 108
_Azolla caroliniana_ 110
Barren Stem of _Equisetum arvense_ 113
Fertile Cones of _Equisetum maximum_ 115
The Dutch Rush 120
HOW TO KNOW THE
FERNS
CHAPTER I
THE FERNS AND THEIR ALLIES
In its lowest forms vegetable life is a very simple affair. The minute
Algæ which clothe damp surfaces with a green film show few indeed of the
characteristics with which we are familiar in the higher plants.
Certainly they are green, proving that the tiny cells of which they are
composed contain the wonderful colouring matter—chlorophyll, by means of
which they are able to assimilate carbon from the carbonic acid of the
air. There is, however, in these lowly plants no sign of a stem, a leaf,
or a root. As we ascend in the scale of vegetable life we begin to get an
increasing number of distinctive characters. In the case of the Mosses we
have plants with distinct stems and leaves. But Mosses have no true
roots, neither is there any vascular (woody) tissue in their composition.
Mounting yet higher in the scale we come to a very important and
interesting group of plants usually referred to as the Vascular
Cryptogams. In this group are included the Ferns, the Horsetails, and the
Club Mosses. In passing, it may be pointed out that the term Cryptogam is
a name which was originally given to the flowerless plants by Linnæus to
indicate that the plan of fertilization was hidden. The name is still
retained, but it has lost its meaning in this sense, in that since the
introduction of high-power microscopes it is not necessarily more
difficult to study the fertilization of the non-flowering plants than it
is to watch the process in the kinds which bear blossoms.
A small acquaintance with the Vascular Cryptogams will show us that they
approach very closely to the flowering plants, or Phanerogams, as they
are called, in their general features. It is true that in the cases of
the Club Mosses and Horsetails the leaves are small or very poorly
developed, but with the Ferns the foliage is often of an advanced type.
All the Vascular Cryptogams, apart from a few insignificant exceptions,
produce real roots; and, as the name implies, in a botanical sense,
evidence woody tissue in their composition. Whilst the Club Mosses and
Horsetails are comparatively humble plants, the Ferns have reached a
remarkable development in the arboreal species. These, of course, grow
into large trees which may be fifty or more feet in height, with thick
woody trunks. Our common Male Fern not infrequently forms a short
trunk-like stem if it is allowed to remain in an undisturbed state for a
number of years. Not all the Ferns are large or even of moderate size;
many of the Filmy Ferns are so minute that they are often taken for
Mosses by those who do not know any better.
All the Vascular Cryptogams show an alternation of generation; that is,
in the life history of each plant there is a sexual and an asexual
individual. As is fully explained later, the plant which arises from the
spore of the Vascular Cryptogam is quite an insignificant body known as
the prothallus. This has a comparatively short existence in most cases.
It is on the prothallus, however, that the sexual organs are produced,
and after fertilization the plant as we know it arises. This individual
is called the sporophyte. The plant is responsible for the spores which
are produced in little cases called sporangia. These are borne straight
on the leaves, and are produced without anything in the way of
fertilization having taken place. As far as the Ferns are concerned, the
spores are all of one kind, but in certain of the Club Mosses two kinds
of spores are produced.
Apart from a few exceptions the Vascular Cryptogams are mostly perennial
in habit. In many cases other means of reproduction are available than
the agency of spores. It is believed that the Bracken Fern is rarely
reproduced by its spores. The increase of this plant seems to be very
effectively carried out by means of the strong growing underground stems
which shoot about in all directions. The Horsetails commonly propagate
themselves in the same way, and it is this which makes them so difficult
to eradicate in the garden. In the case of many Ferns a common mode of
increase is that of budding off new plants on the leaf. The well-known
New Zealand species, _Asplenium bulbiferum_, produces little buds on its
fronds; these grow into small plants, so that each leaf may be
responsible for dozens of new individuals. An even more singular case is
the so-called Walking Fern from North America (_Scolopendrium
rhizophyllum_), which bears long, tapering leaves something like our
Hartstongue. These bend over in such a way that their tips touch the
ground; on the point of the frond a bud is developed. Roots go down into
the soil from the point of the frond, leaves shoot upwards, and thus a
new plant is born. In some species of Club Moss the increase of the plant
by spore production is supplemented by a plan which involves the bearing
of bulbils on the shoots. These are vegetative processes which give rise
to new individuals when they tumble to the ground.
It is of interest to consider the general characteristics of the members
of the Fern tribe. As a rule the stem is either in the nature of a short
underground process bearing a rosette of leaves, as in the case of the
Male Fern and Hartstongue, or there is a horizontal stem more or less
below the surface of the soil, such as is to be seen in the case of the
Bracken Fern and the Polypody. Sometimes the stem assumes the proportions
of a trunk, but these Tree Ferns only occur in the tropics. Where the
stem of the Fern is upright it is properly termed a caudex, whilst in its
horizontal form it is spoken of as a rhizome. There is actually some
doubt as to the real nature of the frond of the Fern. Some botanists are
inclined to believe that it is not really a leaf at all, but is a
modified stem structure. Those who hold this view consider that the
curious scaly structures so common amongst Ferns are really the leaves of
the plant. Here the matter must be left on the present occasion, as it is
proposed to use the terms leaf and frond as meaning the same thing.
An outstanding feature in the case of most Ferns is the remarkable manner
in which the fronds are subdivided. In the case of the Male Fern it is
seen that the upper part of the stalk, or rachis, as it is called, bears
two rows of leaflets. These leaflets are properly referred to as pinnæ.
When the leaflets are subdivided the divisions are spoken of as pinnules.
These pinnules may be deeply lobed, and when this is the case each lobe
is called a segment. In very large fronds the pinnules are again divided;
the frond is then said to be tri-pinnate. Sometimes towards the top of
the pinnæ or the frond the divisions become less pronounced; this
character is designated pinnatifid. It should be noticed that the lower
portion of the stalk, on which there are no pinnæ, is called a stipes. Of
course in some cases, as with the Hartstongue, the leaf is quite
undivided, without even any very pronounced indentations on the margin.
The unrolling of the Fern frond is a very beautiful process. Where the
leaf is not divided in any way the process of expanding resembles the
uncoiling of a watch-spring. Even where there are divisions the unrolling
goes forward in the same manner with each subdivision, even down to the
lobes. This particular mode of unfolding is called circinate. The texture
of the leaves of Ferns is mostly thin and delicate, so that apart from
some exceptions the foliage is not able to withstand the action of dry
air. A notable feature with a large number of Ferns is the length of time
which the leaves take to develop. The fronds of the Male Fern, for
instance, start in the bud at least two years before they actually
unfold. An examination will show that the roots of the Male Fern spring
from the frond bases. It will be found that the position of the roots is
the same in all Ferns.
With all Ferns the production of spores is confined to the leaves. In
many instances there is no distinction between the fertile and the barren
leaves. The stem does not start at once to produce leaves bearing the
sporangia or spore cases. Thus, in the very young Fern the fronds are
always barren; as the stem becomes older, fertile fronds are produced. In
some cases the sporangia are borne on distinct leaves, as in the case of
the Hard Fern, or on special parts of the leaves, in the manner to be
seen in the Royal Fern. The difference in such cases is not really a very
important distinction. A careful examination of the fertile portion of a
Royal Fern frond will show a small amount of green tissue, or mesophyll,
as it is called, at the lower portion of the pinnæ. Actually the fertile
leaf, or part of a leaf, is similar to the barren portions, save that it
produces a much reduced amount of green tissue or, in some cases, perhaps
none at all.
In general appearance the Club Mosses bear a resemblance to the true
Mosses, and hence the popular name, which is certainly rather misleading.
With these plants the leaves are small and almost bristle-like, and are
gathered closely round the stem. In many of the Club Mosses a large part
of the stem lies closely along the ground, and from this at intervals
roots are sent down into the soil and leafy shoots rise upwards. The
sporangia are produced on special leaves, which are usually gathered
together in the form of cones.
Although they vary somewhat in size, all the Horsetails are striking
plants. Here there is a branching underground rhizome from which arise
the aerial stems. The most distinctive feature of the plant are the
whorls of smaller branches which arise from the joints of the main stem.
These carry on the work which is usually assigned to the foliage of the
average plant,—that is, the assimilating of carbon from the carbonic acid
of the atmosphere. The real leaves of the Horsetail are much reduced in
size, and take very little part in the work of nutrition. We shall find
them at the joints of the stem as rings, each collection forming a kind
of sheath. The leaves, which are usually of the same number as the
branches, show no sign of their individuality, save in the little
projecting teeth. In some species the fertile shoots, which appear in the
form of cones, are produced specially. These appear in the spring before
the ordinary vegetative growths, and are quite destitute of chlorophyll.
In other species the normal green shoots are fertile at the termination.
The sporangia are borne on curious scale-like leaves, a large number of
which go to the making of a cone.
One or two aquatic plants, which belong to the Vascular Cryptogams, call
for comment. The Pillwort is a singular plant not uncommon in damp
situations. The leaves of this plant are narrow, and the spores are
produced in curious rounded processes. The Water Fern (_Azolla_) is an
introduced plant which sometimes grows abundantly on lakes in the South
of England. Both the before-mentioned plants are allied to the Ferns. The
Water Club Mosses (_Isoëtes_) are represented in this country by a
species commonly known as the Quillwort. This plant grows in lakes, and
is easily recognized by its quill-like foliage.
Owing to the large number of species a somewhat elaborate classification
is necessary in the case of Ferns. In distinguishing the different
families, the manner in which the collections of spore cases, known as
sori, occur, as well as the features which the individual sporangia
present, are important guides. The actual position of the sorus on the
leaf, the presence or absence of a covering (indusium), are also
distinctive features, both in the families and sub-families. When the
individual sporangium is examined it is found that there is often present
an annulus, a special ring of cells which plays an important part in the
rupturing of the case. The extent of this ring or (as sometimes happens)
its absence will alike be a decisive factor in fixing the family to which
a species belongs. In some families a prominent feature is the fact that
the sporangium has little or no stalk, although this is the exception
rather than the rule. For a more complete description of the sporangium
of the Fern the reader is referred to a succeeding chapter. It is
certainly helpful to a study of these beautiful plants to try to fix in
the mind the families, and their characters, of the order _Filices_. In
all there are eight families belonging to the Fern tribe. These are given
in the order in which they occur in technical books.
1. _Hymenophyllaceæ._—The Filmy and Bristle Ferns. This family includes
some of the simplest kinds of Ferns. There are only three representatives
in the United Kingdom. These are _Hymenophyllum tunbridgense_, _H.
Wilsoni_, and _Trichomanes radicans_. The two former species are fairly
common on rocks which are splashed with water, but the latter seems only
to occur in restricted districts in the South of Ireland. All the species
must have an abundance of water, or the foliage quickly shrivels. This is
due to the fact that the leaves consist of a single layer of cells and
are, of course, very thin. A distinctive feature in this family is the
bearing of the sporangia; these are almost or entirely stalkless. The
sorus, as the group of sporangia is called, is surrounded by an enclosure
from the leaf margin. In _Trichomanes_ this is cup-shaped, whilst in
_Hymenophyllum_ it is bivalved. The popular name Filmy Fern—bestowed on
the Hymenophyllums and allied species—has reference to the
semi-transparent nature of the fronds. In the case of _Trichomanes_ the
axis on which the sporangia are inserted often projects beyond the cup in
which they are contained. This gives a curious spiky appearance to the
fertile frond, and hence the name Bristle Fern.
2. _Polypodiaceæ._—This is a very large family, containing two or three
times as many species as all the rest of the Vascular Cryptogams put
together. Nearly all our native species, with a few exceptions, belong to
the family. A distinctive feature is the incomplete annulus of the
sporangium. Another point to notice is that the spore cases are stalked.
So large is the family that it has been divided into a number of
sub-families; the members of these are chiefly characterized by the
position of the sorus, the cluster of sporangia on the back of the frond.
The different sub-families may be briefly outlined.
(_a_) _Davalliaceæ._—There are no British representatives of this family.
In this case the sorus is always near to the margin of the leaf, and the
indusium or covering is cup-shaped. A familiar species is _Davallia
bullata_ from the East; the rhizomes of this Fern are trained into
various shapes by the Japanese.
(_b_) _Pterideæ._—The Bracken Fern (_Pteris aquilina_), the Maiden Hair
(_Adiantum capillus-veneris_), and the Parsley Fern (_Cryptogramme
crispus_) belong to this sub-family. A notable feature of the Bracken is
the continuous marginal sorus. There is no proper indusium, but the leaf
margin curls over and protects the sporangia to some extent.
(_c_) _Aspidieæ._—The sorus is in the form of a little rounded heap. The
indusium, which is usually kidney-shaped, is supported by a central
stalk, somewhat after the manner of a nasturtium leaf. The Male Fern
(_Nephrodium filix-mas_) belongs to this sub-family, as well as the
Bladder Ferns (_Cystopteris_) and the _Woodsias_.
(_d_) _Asplenieæ._—Here the sorus is elongated or linear. The indusium
arises from a vein to which the sorus is attached. Some very charming
Ferns belong to this sub-family. Many botanists include the Lady Fern
(_Athyrium filix-fæmina_) in this section. Certain of the Spleenworts
(_Asplenium_) are common. The Wall Rue (_A. ruta-muraria_) and the Black
Maidenhair Spleenwort (_A. adiantum-nigrum_) are well known.
(_e_) _Polypodieæ._—The sori on the underside of the leaves are without
any indusium. They are in rounded clusters, and look like small buttons.
_Polypodium vulgare_ is one of our commonest Ferns. Some of the other
species of this genus, such as the Oak Fern (_P. dryopteris_) and the
Beech Fern (_P. phegopteris_), are abundant in some localities.
(_f_) _Grammitideæ._—The Gold and Silver Ferns. The only British species
is the Annual Maidenhair (_Gymnogramma leptophylla_). The plant occurs in
the Channel Islands. This species is one of the few Ferns which are not
perennial. The sori, which follow the veins, have no indusium.
(_g_) _Acrosticheæ._—There are no British representatives of this
sub-family. In this case the whole of the underside of the leaf is
covered with sporangia, and there is no indusium.
3. _Cyatheaceæ._—There are no British representatives of this family,
which is interesting, owing to the fact that it includes the Tree Ferns.
4. _Gleicheniaceæ._—A group of Ferns which are almost entirely tropical.
5. _Schizæaceæ._—Another tropical family.
6. _Marattiaceæ._—A family of large and handsome Ferns, the members of
which occur in the tropics. There are not many representatives of this
family nowadays, but remains in the Coal Measures show that the species
were very much more numerous in Palæozoic times.
7. _Osmundaceæ._—A small family, but rather an important one, owing to
the fact that a leading representative, the Royal Fern (_Osmunda
regalis_), is so well known. In this species only the upper portion of
the leaf is fertile. The sporangia have very short stalks, and are not
provided with an annulus at all. They burst open in a longitudinal slit,
opposite to a special group of cells just below the apex. The sorus has
no indusium.
8. _Ophioglosseæ._—This family is represented by three British species,
of which the Moonwort (_Botrychium lunaria_) and the Adder’s Tongue
(_Ophioglossum vulgatum_) are best known. There is much doubt as to
whether this family can be properly included amongst the Ferns at all. We
may here give them the benefit of the doubt. The leaves in these species
are unfolded from the sides—a totally distinct plan from that to be
observed in all the Ferns which have been described, where the frond and
its divisions are unrolled upwards. The prothallus is a small underground
body destitute of chlorophyll. The fertile leaves are distinguished from
the barren ones by the production of a special branch which bears the
fructification. The sporangia are large.
The next order of the Vascular Cryptogams is of comparatively small
importance as far as the present study is concerned. It is known as the
_Rhizocarpeæ_ (Pepperworts). The order is divided into two families as
follows:—
1. _Salviniaceæ._—The only two genera are Salvinia and Azolla; the latter
has been already mentioned.
2. _Marsiliaceæ._—The British example is the Pillwort (_Pilularia
globulifera_).
The Club Mosses have been divided into six families. Two of these—the
_Lepidodendraceæ_ and the _Sigillariaceæ_—are only represented by
fossils; and one, _Psilotaceæ_, has no British representatives. The
remaining families all include one or more species which are indigenous
to our islands.
1. _Lycopodiaceæ._—These are the Club Mosses proper. Several species of
the genus _Lycopodium_ are British. The Common Club Moss (_Lycopodium
clavatum_) is often abundant on high moors.
2. _Selaginellaceæ._—A large family containing three or four hundred
species, only one of which, however, is British; this is _Selaginella
spinosa_.
3. _Isoëtaceæ._—A family of aquatic Club Mosses. The British species is
_Isoëtes lacustris_, a plant which is sometimes common in the northern
lakes.
With this brief survey of the Vascular Cryptogams one may naturally pass
to a somewhat more detailed consideration of the life histories of these
interesting plants than it has been possible to give in an opening
chapter.
CHAPTER II
LIFE HISTORIES
Even the most general survey of the Vascular Cryptogams would not be
complete without an attempt to indicate the means of reproduction to be
observed in these plants. The subject is one which might well be treated
at great length, for there is scarcely any species which does not present
some interesting point that calls for comment. Within the limits of the
present inquiry it will not be possible to give more than an outline of
the reproductive schemes to be observed in a few typical species. These
life histories must not be taken as necessarily applying to all the
related plants. None the less, by a careful study of the species
described we may receive a fair conception of the habits of the class to
which it belongs. Incidentally it may be mentioned that even a low-power
microscope will be an enormous help in studying the life histories of the
Vascular Cryptogams; but if this is not possible, a pocket-lens will help
to a better understanding of many of the points described.
For the study of the life history of a Fern one cannot do better than
take the commonest of our native species, the Male Fern (_Nephrodium
filix-mas_). Seeing that the general aspects of the plant are fully
described in a later chapter, there is no need to enter into such matters
at the present moment. We may, however, examine a fertile leaf of the
Fern in order that we may start at the beginning of a really interesting
romance. A very small magnification of the brown patches on the back of
the frond, which we remember are called sori, will reveal their true
character. After removing the kidney-shaped cover (indusium) we shall be
able to see the spore cases or sporangia quite clearly. Each of these
consists of a capsule borne on the end of a stalk. These sporangia are
seen to grow out from the sides of a mass of special tissue, known as the
placenta, from which the indusium really arises. On occasions a curious
club-shaped hair which secretes resin can be observed on the stalks of
the sporangia. There seems to be no satisfactory explanation as to the
part which this process plays. The capsule of the sporangium is much
flattened, and has not been inaptly compared to a watch-case. Its wall is
very thin, being composed of a single layer of cells. Around the edges of
the little case there is a row of large and thickened cells which form
the ring or annulus. Here it may be mentioned again that the structure of
this annulus varies greatly in the different families, and is often a
useful distinguishing feature. To return to our Male Fern, the annulus is
plainly seen to start from the stalk of the sporangium at one side of the
capsule, and it can be traced right over the top to a situation about
half-way down on the other side. The chief business of the annulus is to
bring about the opening of the sporangium in such a way that the spores
are violently expelled. This happens in the following manner. When the
contents of the sporangium are mature the wall of the capsule, and
especially the cells forming the annulus, begin to lose water. The sides
of the capsule start to draw inwards, and ultimately the annulus suddenly
straightens out and the sporangium is torn open, the actual rupture
taking place just at the base of the ring.
The manner in which the spores originate in the sporangium calls for
comment. In the case of the Male Fern these arise owing to the repeated
division of a single cell. At a certain stage in the process there are
produced what are known as mother cells. Ultimately these divide twice,
and the resulting cells represent the spores. When ripe, the spores
become kidney-shaped and the wall of the cell takes on a rich brown
colour. In the different kinds of Ferns, the form of the spore and the
sculpturing of its walls vary a great deal. Thus the spores may be
globular, oval, or angular in shape; whilst the exterior may be quite
plain, or, perhaps, most beautifully marked. The number of spores
produced in the sporangium of a Male Fern is usually some forty-eight to
sixty-four, although in other species there might be less than the lower
figure or more than the higher. To the naked eye the spores appear to be
so much dust, and as they are comparatively light they float away on the
breezes, and often enough travel for a considerable distance before
coming to rest. As a rule the bursting of the sporangia takes place
during dry weather. There is a real advantage in this, for when the
spores are damp they hang together in masses and in such a state a wide
dispersal would be out of the question.
The best thing that can happen to the spore is that it should settle upon
some moist soil. Here it may be mentioned a most instructive experiment
is the sowing of a few fern spores. This may be carried out in ordinary
garden soil, although it is wise to sterilize it before use. All soil
contains the germs of such organisms as mould which, in cultivation at
any rate, is especially destructive to developing spores. The plan is to
bake the mould in an oven until it is so hot that one cannot bear to
touch it. We shall get any number of spores from the fertile leaf of a
Male Fern by just tapping the frond whilst holding it over the surface of
the soil. Do not scatter the spores too thickly, or it will be difficult
to examine the stages of development, and remember also that the soil
should be moist at the start. The results of this spore culture are
always more satisfactory if the soil is covered with a bell-glass—an
ordinary tumbler would do if nothing better is available. Water must be
given as necessary, though do not swamp the soil; the best plan is to let
the liquid in a few drops at a time.
In the case of the Male Fern the germination of the spore will start in
about eight days, but in other species the period varies. Many of the
succeeding stages cannot be intelligently followed except with the aid of
a microscope. The first thing which happens to the germinating spore is
the development of a root hair which helps in fixing the process to the
soil. A system of cell division now commences in the other portion of the
spore which results in the formation of a green filament, every cell of
which is capable of producing root hairs. This filament is the beginning
of the body, known as the prothallus, which is responsible for the sex
organs. The process of cell-division goes forward and ultimately results
in the development of a green scale measuring, perhaps, an eighth of an
inch across at its broadest part. This is the fully-grown prothallus.
From the underside arise more root hairs, and it is here also that the
antheridia (male organs) and the archegonia (female organs) are produced.
As a rule, both kinds of organs occur on the same prothallus, although
now and again prothalli have been discovered which are exclusively male
or female. The matter is of interest, because it evidences an occasional
distinction of sex which has become habitual in some of the Club Mosses.
In the case of a perfectly normal prothallus the male organs or
antheridia are to be found amongst the root hairs, whilst the female
organs or archegonia arise from a cushion, several cells deep, more
towards the centre of the process.
The manner of fertilization may be briefly outlined, although the
observation of this is beyond the ordinary student. With Ferns, as is the
case with nearly all the Cryptogams, the fertilization takes place under
water; the moisture may be the outcome of heavy rain or even dew. However
that may be, as soon as the underside of the prothallus has become
thoroughly wetted the antheridia open, and certain little bodies called
spermatozoids are allowed to escape. These are exceedingly active, and
are in the form of spirally coiled bodies with a number of fine threads
(cilia) at one end. The same moisture which caused the antheridia to open
also brings about the opening of the archegonia. Some time ago it was
shown that the spermatozoids steered a decided course towards the
archegonia, but the reason for this has only been comparatively recently
explained. At the mouth of the archegonia there is a viscid drop which
almost certainly contains chemical substances attractive to the
spermatozoids. Although the nature of the substance is not exactly known,
it is suggested that this may be malic acid, seeing that experiments have
shown that the spermatozoids are attracted to this product when it is
artificially introduced. Of course the matter is a difficult one to
prove, in that the viscid drop is so minute that it is impossible to
determine the nature of the substance which it contains. Malic acid has,
however, been discovered to be present in the prothallus as a whole.
Although there is quite a competition amongst the spermatozoids as to
which shall enter the archegonium, it is likely that only one actually
succeeds in entering the egg cell. As a rule, too, in the prothallus only
one of the archegonia shows any further signs of development.
After the fertilization is completed the first happening is the formation
of a cell-wall round the ovum. Passing through various stages of growth
and subdivision it finally forms the embryo of the young plant. For a
while the newly-born Fern relies upon the prothallus for sustenance, but
eventually starts an independent existence. The baby sends down roots
into the ground and leaves up into the air, and from thenceforward its
development into a mature plant will only be a matter of time.
The life histories of the Club Mosses have certain points which make them
of special interest. In the first place, the manner of reproduction to be
observed in the Lycopodiums may be outlined. Sometimes the sporangia are
borne on fertile leaves which exactly resemble the ordinary ones; a good
instance of this is seen in the case of the Fir Club Moss (_Lycopodium
selago_). On the other hand, the fertile leaves may be gathered together
into cones such as are to be observed in the case of the Common Club Moss
(_L. clavatum_). The sporangium is quite a large affair, easily discerned
with the naked eye. The number of spores produced is enormous—so much so
that these can be shaken out in a thick powder. In some of the
Lycopodiums the spores have a remarkable habit of resting before the
development of the prothallus. It is said that in the case of the Common
Club Moss the prothalli do not appear until the end of the sixth year.
Even then, several more years elapse before the prothallus is
sufficiently mature to bear the organs of sex. In the case of _L.
inundatum_ the length of time which elapses between the coming of the
prothallus is nothing like so great. With all the Lycopodiums, however,
the prothallus, which varies a good deal in the different species, bears
both kinds of sexual organs. In most of the cases where the development
of the spore is such a long business the prothallus is produced
underground. With _L. inundatum_, however, the prothallus is green and
leaf-like. The underground prothalli have no chlorophyll, and hence
cannot live the life of an independent green plant. It has lately been
demonstrated that these are always found in conjunction with a certain
fungus; probably the benefits of the association are mutual. Making
allowance for certain differences which are not of great importance to
the general student, the fertilization of the egg cell in the prothallus
of the Lycopodium is carried out on very similar lines to those which
have been described in the case of the Fern.
The life histories of the Selaginellas evidence some important
differences which call for special comment. Here throughout the whole
family the spore-bearing part of the plant is in the form of very
definite cones. As in the case of Lycopodium there is only one sporangium
to each leaf, but they are of two kinds. One, on account of the fact that
it is responsible for the production of small spores, is called the
microsporangium; the other, the megasporangium. The two kinds of
sporangia are usually present on the same cone, although the
microsporangia are as a rule higher up the stem than the megasporangia.
The number of microspores produced is very large, but only four
megaspores are borne in each megasporangium. The megaspores are, of
course, very much larger than the microspores. The germination of the
megaspores is started in the sporangium; at a certain point in their
development they are shed. In the case of the microspores germination
commences after the spores have fallen on to moist soil. The prothallus
is exceedingly small, being little more than a group of cells forming an
antheridium. Should there be sufficient moisture about, the spermatozoids
which are produced by the antheridium swim towards the archegonia in any
female prothallus which may be near. Fertilization then takes place, and
the final outcome is the young plant. Now and again in certain species it
is seen that the megaspores develop to such an extent within the
sporangium that fertilization takes place, and even an embryo or young
plant may be formed.
There remains to be considered the life history of the Horsetails. The
spores are always produced on special processes, which are arranged in
the form of a cone at the apex of the stem. The sporangia are borne on
curious scales which are supported by stalks placed in the centre. These
scales are arranged in whorls round the centre of the stem, and there may
be twenty or more in each row. On the underside of these scales we shall
find the sporangia—almost any number of them up to ten. Each sporangium
produces a considerable number of spores, so that every cone is
responsible for an enormous number. These spores are all of one kind, and
they are so singular that they are worth a somewhat detailed description.
The covering of the spore really consists of four layers, the outermost
of which is split spirally in such a way that two long arms with
flattened ends are produced. As long as the spore is damp these remain
closely gathered round, but under dry conditions they are stretched out.
The movements of these arms or elaters, as they are called, are readily
watched under a microscope. By gently breathing on the spores we bring
them under the influence of moist air, and this causes the elaters to
curl up; after a while, however, when they become dry, the arms stretch
out again. It is not certainly known what is the use of these elaters. A
very little observation shows that the opening and closing of the arms
keeps the spores on the move; this would aid dispersal at the time of the
bursting of the sporangium. Another point which is worth consideration is
that although the spores appear to be exactly the same, yet as a rule
they develop on distinctive sex lines. It is obviously important that the
male and the female prothallus should be together. The long arm-like
processes on the spores often link the little bodies side by side, and
this would be an advantage.
The spores of the Horsetails are not long in developing after they have
settled in a damp situation. The actual forms which the prothalli take
are often very irregular. That of the male prothallus is usually rather
small; on the other hand, the female prothallus is sometimes large, and
may have complicated branchings. As in the case of the other Vascular
Cryptogams which have been considered, spermatozoids are produced in the
antheridia. These are very active, and travel through the agency of water
to the archegonia on the female prothallus. The spermatozoids unite with
the various egg cells, and in this way an embryo is formed which finally
develops into the mature plant. Owing to the fact that the prothalli of
the Horsetails have proved to be excessively difficult to cultivate, the
life history has not been so completely worked out as in the case of the
Ferns and Club Mosses. One interesting point in connection with the
cultivation of Horsetail spores has been brought to light. Whenever the
spores are growing on poor soil, by far the larger number of them produce
antheridia. On the other hand, where there is plenty of nourishment the
tendency is all the other way. The matter is of interest, as it appears
to show that the amount of available nutriment is a definite factor in
the determination of sex.
CHAPTER III
YESTERDAY AND TO-DAY
Although to most people the study of fossil botany may appear to be an
uninviting pursuit, there can be no question as to the importance of the
science. It is only in this way that we are able to appreciate the
changes which have led up to the existing types of plants. Now the
question of the past history of the Vascular Cryptogams is of very
special interest in more ways than one. It is, of course, most
fascinating to be able to discover what kinds of Ferns flourished, for
instance, at the period when the coal deposits were being formed. But,
even in a cursory description, it will be quite impossible to allow the
matter to rest there. The story of the past, in the case of the Vascular
Cryptogams, is closely interwoven with some of the most absorbing phases
in the evolution of the Flowering Plants which are such a dominant
feature on the earth at the present time.
Quite recently we have had to alter our views materially on the matter of
the past history of the Ferns. Within the last few years it has been
proved that a huge number of the fossil remains, belonging to the
Palæozoic formation at any rate, are not Ferns at all. They belonged to a
very distinct race of plants altogether, known as Pteridosperms, even
though they had a superficial resemblance to Ferns. After a large amount
of patient research it has been demonstrated that these plants bore
seeds. The method of flowering and seed-production was vastly different
from that which is to be observed in the flowering plants of to-day. The
male or pollen-bearing organs were produced straight on the foliage in
much the same way as the sporangium of a true Fern is developed. In a
similar manner the seeds were borne straight on to the leaf. In some
general points these plants also bore a strong resemblance to the Ferns,
and it was this which misled the early observers. Without a doubt these
Pteridosperms were related to the Ferns, and probably at some remote
period the two groups had a common ancestry. There is good reason for
believing that at the same time these Pteridosperms were flourishing true
Ferns were also well represented.
Now the interesting point about these Ferns is that they were not vastly
different, in many ways, from the species which exist on the earth at the
present time. Of course certain types, of which we have living examples,
were more fully represented than is the case nowadays; on the other hand,
some of our most widely distributed families seem to have been at rather
a low stage in their history. As well, the remains evidence a large
number of very simple species, which perhaps give us an idea of what the
original Ferns were like. But on the whole there is nothing to show that
our living Ferns are any more developed than the highest types which grew
in the coal forests. In these far-away times there were Tree Ferns; but
so there are, of course, at the present time.
The early botanists who strove to prove that Ferns were, so to speak, the
last development before the Flowering Plants were not, perhaps, very far
from the truth. It has been seen that during the period when the coal
deposits were being formed there flourished side by side races of true
Ferns and Fern-like plants which bore seeds—the Pteridosperms. The point
has also been suggested that in all probability these two groups of
plants had a common origin. With the coming of later times (the
Cretaceous and Jurassic periods) there appeared the Bennettiteæ. These
remarkable plants seem to have entirely taken the place of the
Pteridosperms, and were an enormous advance towards the Flowering Plants
of the present day. Only recently have the Bennettiteæ been properly
described and their interesting features fully understood. We have a few
representatives of this important group in the Cycads, plants bearing a
superficial resemblance to Palms, but actually very different in all
other ways. By the manner in which the reproductive organs are produced,
and the way in which the scheme is carried out, these Bennettiteæ appear
to be a half-way house between the cryptogams and the advanced flowering
plants. The stamens bearing the pollen are produced on the fronds very
much like the sporangia of Ferns. On the other hand, the seed-bearing
structures are collected together into a sort of pistil. This was borne
at the tip of the branches and ended their growth, just as happens in the
case of Flowering Plants. For some reason which we cannot understand
these Bennettiteæ seem to have fallen back in the race for supremacy, for
the group is but poorly represented in our modern Cycads and a few allied
plants. In all the world there are perhaps not more than about a dozen
species, the sole survivors of a race which at one time dominated the
world. There seems every reason for thinking that the Flowering Plants
arose as an offshoot of the Bennettiteæ, and in some way secured an
advantage which enabled them to arrive at their present position.
When we come to consider the past history of the Club Mosses the record
is of a different nature to that of the Ferns. Nowadays the Club Mosses
are not of great importance in the world, even though, as will be shown
later, the number of species is considerable. But when we travel back to
Palæozoic times, particularly in the coal period, it is evident that
these plants were represented by a number of very large and dominant
families. Some of these early Club Mosses certainly came very near to
rivalling the Flowering Plants. Probably the tendency of the world to
become drier has had something to do with the decline, seeing that in all
cases the fertilization is carried out under water. We may gather some
idea of the importance of the Club Mosses in Palæozoic times from the
fact that in every part of the world where coal deposits have been
examined great numbers of the fossil remains of these plants are always
discovered. Many of these grew into large trees which were a hundred or
more feet in height, sending out great branching shoots above and an
enormous root system below.
From a botanical point of view there is no doubt that some of the Club
Mosses, particularly those belonging to the family _Selaginellaceæ_, have
approached very nearly to the Flowering Plants. At the present time the
existing species, the Selaginellas, bring us up to the very threshold of
the dominant group. The lowest division of the Flowering Plants is the
_Gymnospermæ_ (which includes the Conifers), and it is interesting to
note the points of similarity between a typical Gymnosperm and a
Selaginella. To start away with, the Selaginella bears two kinds of
spores, each of which in its development has a definite sex character.
The smaller ones (microspores) are in their manner of production
analogous to the pollen-grains of the Flowering Plant. The prothallus and
the male organ (antheridium) are comparable to the special cell-group in
the pollen-grain, whilst the spermatozoids approximate to the generative
cells. In the larger spores (megaspores) these represent the embryo sac,
and the sporangium in which they are produced closely approximates to the
part containing the embryo sac in the Flowering Plant. The prothallus
which arises from the megaspore in the Selaginella closely resembles the
endosperm—a special tissue formed to feed the embryo in the case of
flowering plants. The female organ (archegonium) and the cell which it
produces are practically identical in both cases. Fossil remains have
shown that some of the plants like Selaginella which flourished in
Palæozoic times seemed to have come very near to the production of seed.
Thus one species which has been described shows a megaspore which was
permanently within the sporangium, and which in its general development
greatly resembled a fruit. It is, of course, impossible to give more than
a very brief outline of some of the chief points in this highly important
comparison between the Gymnosperm and the Selaginella. The author trusts
that those of his readers who are interested will pursue the study in the
admirable textbooks which are now available.
The Horsetails, like the Club Mosses, have had a very important past.
Although they are few in number, as far as the species are concerned,
they still retain many striking characteristics. Without a doubt the
Palæozoic Horsetails grew into giant plants, sending out branches and
developing trunks which in some ways are comparable to those possessed by
our trees at the present time. These great stems seem to have arisen from
rhizomes which travelled about in the mud of the coal jungles. It is
usual to refer to these Palæozoic Horsetails as Calamites, owing to the
fact that they were originally supposed to bear a resemblance to a reed
(_Calamus_). In the later rocks, such as those which belong to the
Jurassic and Triassic periods, occur the Equisetites, plants which were
still of great size, but already in some respects showing signs of that
decline which has culminated at the present day in the little group of
plants which, were it not for a certain robustness of growth, would find
it hard to maintain their position at all.
To complete our brief survey of the Vascular Cryptogams it is now
necessary that we should review the position of these plants at the
present time. Of course in number the Ferns are enormously in advance of
all the other plants put together. In the whole world, there are not far
short of seventy distinct genera, which include anything between three
and four thousand species. The Ferns of the United Kingdom number not far
short of fifty, and there are certain variations from the type which some
folk are tempted to include as species. For some reasons which we cannot
well understand, the Ferns alone amongst the Vascular Cryptogams have
been able to hold their own in the world. It is probable that there are
quite as many species, and that these are as varied, to-day as has ever
been the case. The size of Ferns, as we have already seen, varies
enormously. In the tropics and in Australasia there are Tree Ferns eighty
feet in height, whilst with many of the Filmy Ferns the size is scarcely
larger than that of Mosses. Owing to the fact that it is so necessary in
the scheme of reproduction, the majority of Ferns are lovers of moisture.
None the less, a few specimens have adapted themselves marvellously to
drier conditions. Thus the Bracken will grow on the exposed hillside or
cliff-top even where its rhizomes cannot carry the roots to a great
amount of moisture. Some of the most interesting species of Ferns are
those which grow on walls and rocks, where there is little dampness,
during the summer at any rate. Many of these have adopted special devices
to cope with drought, such as are to be seen in the Scaly Spleenwort.
Here the underside of the frond is covered with hairy scales, and in dry
weather the leaves roll up so that the well-protected underside is alone
exposed to the sun. After all, however, Ferns are most at home where
there is a comparatively deep shade with abundance of moisture. Many
species which will grow in somewhat dry situations attain a much finer
development under happier conditions.
Luckily many kinds of Ferns are still very common in the United Kingdom.
Of course, in much-visited localities the ravages of the trippers have
practically exterminated some interesting species in these particular
districts. Naturally, one hardly expects to find the Royal Fern
flourishing to any extent in the popular holiday haunts—none the less,
there are still any number of places where this noble plant “grows like a
weed.” The wise man does not talk about such things to his friends. Many
of our most beautiful Ferns are saved even in much-frequented places on
account of the fact that they grow out of reach. No doubt the graceful
Trichomanes of South Ireland would long ago have been stamped out in the
Killarney district, were it not for the fact that it often grows in
situations which it is almost impossible for anyone to reach.
As far as number is concerned, the living Club Mosses represent a
comparatively insignificant group when compared with the Ferns. In all
the world there are probably not more than five or six hundred species.
These are very widely distributed, and there is hardly any part which
cannot offer at least a few species. We have five species of Lycopodium
in the United Kingdom. All are rather local, though often enough they
occur in great abundance in special localities. Only one (_Lycopodium
inundatum_) ever occurs in lowland districts; all the rest must be looked
for on highland moors. A few exotic Lycopodiums grow to a fair size,
though this is largely due to the fact that their creeping stems straggle
along the ground for a considerable distance. The Selaginellas are a much
more important group as far as the world generally is concerned. There
are certainly as many as four or five hundred species, and some of these
assume almost a shrubby habit. A species from Borneo (_S. grandis_) is
said to attain the height of two feet. In the United Kingdom we have but
a single species of Selaginella—_S. spinosa_, an insignificant little
plant. Many exotic kinds are frequently grown in greenhouses, so that a
variety of species is within the reach of everybody.
Authorities vary as to the exact number of species which belong to the
only genus of the Horsetail—_Equisetum_; the estimate is never higher
than forty. Nearly all these plants are striking in appearance, and some
are quite large. A tropical American species is said to attain the height
of thirty feet, though this is not so remarkable when one considers that
the plant has a climbing habit. In the United Kingdom we have at least
eight distinct species. Some of these are exceedingly common, and owing
to their vigorous growth will often hold their own against all comers.
Indeed, the existing Horsetails are, to use a common expression, “putting
up such a good fight” that it is certain they will continue to hold their
own for many a long day. Unlike the Club Mosses, the Horsetails seem to
be quite happy in the vicinity of towns, and are often seen at their best
on railway embankments and in similar situations.
Although the Vascular Cryptogams played an important part in helping to
build up our vast stores of coal, it is astonishing to note of what
little direct economic value they are to mankind at the present time. In
a few parts of the world, where the native races make little or no
attempt at agriculture, the root-stocks of Ferns—often rich in starch—are
eaten. Thus the Maoris of New Zealand and some of the South Sea Islanders
secure a poor kind of sago from some of the Tree Ferns which grow in
their districts. The Japanese use the growing tips of the Bracken as
food. Years ago, Ferns used to be burnt for potash in this country, and
their astringent properties naturally attracted the old-world pharmacist.
They are practically useless as fodder on account of their bitter taste,
and no animal—except, perhaps, the goat—would think of eating Ferns. In
many cases, however, Bracken is used regularly as a bedding-down material
for cattle.
Coming to the Club Mosses, it is even more difficult to find that they
are of any direct benefit. Some kinds in South America are said to yield
a blue dye. Our Common Club Moss is in its huge quantity of spores
responsible for the “Lycopodium Powder” which at one time was employed in
the making of fireworks. The powder is said to be highly inflammable, but
when shaken straight out of the cones it does not always ignite very
readily. One of the Horsetails, the Dutch Rush (_Equisetum hyemale_),
was—and perhaps is still—used in polishing, owing to the large amount of
silica which is present in its stems. In addition, those who are
interested in coast erosion say that the stronger-growing species of
_Equisetum_ should be planted to keep clay cliffs from falling. From an
ornamental point of view the Ferns and some of the Club Mosses are, of
course, of great value. They are widely cultivated in garden and
greenhouse, and we may say that these plants make up in æsthetic value
what they lack from an economic point of view.
CHAPTER IV
THREE DAINTY FERNS
Although the members of the family Hymenophyllaceæ are largely tropical,
we are fortunate in having three representatives in the United Kingdom.
Two of these, both Filmy Ferns, are not so familiar to people as they
might be, if folk were only a little more observant; whilst the Bristle
Fern is only to be found in the South of Ireland. All the species require
an abundance of moisture, and they attain their greatest perfection on
rocks which are dripping with water.
_Trichomanes radicans._ The generic name is said to be derived from two
Greek words—_thrix_, “a hair,” and _manos_, “soft”; the specific name is
obviously connected with the Latin _radix_, “a root,” and has reference
to the creeping rhizome. The Bristle Fern.
[Illustration: Trichomanes radicans. The Bristle Fern.]
This species is quite one of the most beautiful of our native species.
Its fronds are very graceful in form, and are of such a delicate texture
as to be almost transparent. The general outline of the fronds is
triangular in shape. The leaves, varying in length from three inches to a
foot, rise from a black, creeping rhizome, which will often cover a large
area on a moist rock with a perfect network. The stipes or bare portion
of the frond is, as a rule, about the same length as the leafy portion. A
singular feature is a wing-like margin which is present on the upper part
of the leaf-stalk. The frond of the Bristle Fern is divided three or four
times, the first of the pinnæ being placed alternately on either side of
the rachis. The pinnules are deeply cut. The veins of the frond are very
strongly marked. All the divisions of the leaf are more or less curled,
so that the frond as a whole presents a curled appearance.
The sporangia of the Bristle Fern are borne of the veins in the lobes of
the fronds. These are produced in curious cup-shaped processes which are
really formed by the margin of the leaf. The veins pass right through
these receptacles and project beyond the outer edges, thus giving a
curious bristly appearance to the frond as a whole.
The Bristle Fern, as has been indicated, chiefly occurs in the South of
Ireland. It has been discovered in several counties, though it seems to
be best established in the Killarney district. Any attempt to cultivate
this Fern will prove a failure, unless the plants are kept continuously
under a close glass cover where the atmosphere is saturated with
moisture. The Bristle Fern is evergreen.
_Hymenophyllum tunbridgense._ The generic name is derived from two Greek
words—_hymen_, “a membrane,” and _phyllon_, “a leaf”; _tunbridgense_ has
reference to the fact that the species was first of all noticed at
Tunbridge Wells. The Tunbridge Filmy Fern.
The fronds, rarely more than two or three inches long, are of a very dark
green colour, and rise from a slender, creeping rhizome which produces
immense quantities of fine roots. The texture of the fronds is of a
delicate nature, and the veins are strongly marked; in colour the leaves
are dark green. The outline of the fronds is roughly ovate; that is, it
tends to be broadest towards the centre. The pinnæ branch alternately
from either side of the rachis, and these are usually very distinctly
lobed. If examined with a magnifying glass it will be seen that the edges
of the pinnules are bordered with bristling points.
In the case of the Tunbridge Filmy Fern, the sporangia are gathered in a
little cup formed by the margin of the leaf; these are present at the end
of the veins which branch out from the mid-veins of the pinnæ.
[Illustration: Hymenophyllum tunbridgense. The Tunbridge Filmy Fern.]
The Tunbridge Filmy Fern has a very wide distribution in this country. As
a rule the plant grows intermingled with moss, and on this account it is
often passed by without recognition. Almost everywhere where there are
wet and especially water-splashed rocks one may expect to find this
species. The Tunbridge Fern can only be cultivated in the same manner as
that indicated in the case of Trichomanes. The plant is evergreen.
_Hymenophyllum unilaterale._ The specific name is, of course, a Latin
word meaning “one-sided”; the application of the term is explained in the
following description. (In some books this species has been called _H.
Wilsoni_, out of compliment to a Mr. Wilson, who is said to have noticed
the species first of all.) The One-Sided Filmy Fern.
Some botanists have considered that the One-Sided Filmy Fern is merely a
variety of the former species, though it is generally considered to be a
distinct type. The two plants often grow mixed up together and
superficially look very much alike; it is only after a close examination
that the differences become apparent. In a general way it will be found
that in the case of the One-Sided Filmy Fern the fronds are somewhat more
narrow than those of the Tunbridge Filmy Fern. The chief point of
distinction is indicated in the popular name:—if the pinnæ are closely
examined it will be seen that the upper portion is much more divided than
the lower side. Another distinctive point to which attention should be
drawn is that in this species the pinnæ show a marked tendency to curve
backwards.
A study of the fertile leaf of the One-Sided Filmy Fern will also give us
an additional point in the identification. With a magnifying glass it is
plainly seen that the margin of the cup-shaped receptacle into which the
sporangia are gathered has not the toothed border to be found in the case
of the Tunbridge Filmy Fern.
As has been indicated, we may look for the One-Sided Filmy Fern in
exactly similar situations to those which suit the Tunbridge Filmy Fern.
The former species is said to be more common in Scotland and Ireland than
the latter. The One-Sided Filmy Fern is, of course, an evergreen.
CHAPTER V
THE BRACKEN FERN AND TWO INTERESTING SPECIES
Many members of the Fern tribe are of a retiring disposition, and to find
them we must search in out-of-the-way corners. This cannot be said,
however, of the leading subject under discussion in this chapter, for of
all native ferns there is certainly none with a wider distribution than
the Bracken. As one of the few ferns not needing a moist situation, the
Bracken is able to make itself at home almost anywhere, save perhaps in
the vicinity of large manufacturing towns. The sub-family Pterideæ to
which the Bracken belongs has not a large number of representatives in
the United Kingdom. In the Ribbon Ferns and the Maidenhairs of our
greenhouses we have evidence that, as far as the world at large is
concerned, the Pterideæ are very numerous.
_Pteris aquilina._ The generic name is derived from the Greek word
_pteron_, “a wing,” and the specific name comes from the Latin _aquila_,
“an eagle.” The Bracken Fern.
[Illustration: Pteris aquilina. The Bracken Fern.]
The height and general outline of the Bracken Fern varies enormously. On
exposed hillsides the plant may be barely a foot in height, with leaves
correspondingly small. In the sheltered wood it is not an uncommon thing
to discover specimens which may be taller than a man. In such cases the
fronds may measure as much as four feet at their widest parts. The fronds
of the Bracken start to develop—in the South of England at any rate—about
April and are fully expanded by Midsummer. During September they turn a
beautiful golden brown and finally die altogether, although the leaves do
not decay quickly. The Bracken is, of course, a very strong-growing
perennial, and the plant has a wonderful system of underground rhizomes.
In a strong-growing specimen these rhizomes may be as thick as a finger
and are very succulent. They are of a jet-black colour, and at the base
of each frond there are sent out a quantity of fibrous roots. The fronds
arise from either side of the rhizome, and often not more than one or two
are developed in a single season. By examining the rhizome it is possible
to discover the buds containing the new fronds for two years ahead.
The fronds of the Bracken Fern are roughly triangular in outline. That
portion of the stipes which is under ground is of a dark brown colour,
but the portion above the surface is of a bright green tint. The rachis,
or foliage-bearing portion of the stalk, represents about half of the
whole. On either side of the rachis the pinnæ are arranged in pairs,
which are placed nearly but not quite opposite to one another. These
pinnæ are divided again, and in very large examples there may be a
further subdivision. In all the parts of the frond of the Bracken there
is a tendency for less division at the apices of the different portions.
It should be noted that the lowest pairs of pinnules, those next to the
rachis, are often much modified; they are always small, and in some cases
the upper pinnules are missing.
It is along the margins of the lobes of the leaf that the sporangia are
produced. There is no proper indusium, the spore cases being protected by
the rolling back of the margin of the leaf. When the sporangia are mature
the back of the Bracken frond, with its outline of bright brown, is very
pretty. The number of spores produced is prodigious, and it is a common
experience to find one’s boots covered with the brown dust after walking
through the fronds. It is believed that the Bracken is rarely propagated
in a natural state by the agency of its spores. The strong-growing
rhizomes provide a very effective method of increase, and as has been
stated, the Bracken Fern is very quick to claim any land which has been
allowed to go out of cultivation.
The Bracken Fern grows almost everywhere in the United Kingdom. It is,
however, not able to hold its own on mountains of greater elevation than
two thousand feet. There seems to be a popular impression that the
Bracken is a difficult plant to grow in the garden. This is not really
the case, the trouble, as a rule, arising from the careless manner in
which the rhizomes are torn up when the plant is removed. The Bracken is,
of course, a useful subject for placing in shrubberies and under trees,
but seeing that the travelling rhizomes take up a great deal of room, it
should be kept out of the ordinary borders.
_Adiantum capillus-veneris._ The generic name is connected with a Greek
word _adiantos_, which means “dry or unmoistened,” this having reference
to the fact that water rolls off the frond of this Fern.
_Capillus-veneris_ simply means “the hair of Venus,” and this doubtless
refers to the shining black leaf-stalk and its delicate branches. The
True Maidenhair.
[Illustration: Adiantum capillus-veneris. The Maidenhair Fern.]
This is one of the most beautiful of our native ferns, and it would
probably have been exterminated long ago in this country were it not that
it so often grows in inaccessible positions. The True Maidenhair loves a
position which is shady and where moisture is abundant. From a slender,
creeping rhizome, which is black in colour, the fronds arise. These vary
greatly in length, and may measure anything from six inches up to a foot,
or even more, according to the conditions in which the plant is living.
The stipes, which is usually about the same length as the leafy portion,
is jet-black, and like the rachis and all its branchings, is of a very
wiry nature. In a moderate-sized specimen the arrangement of the frond
would be on the following lines. On either side of the rachis the pinnæ
are produced; these usually branch alternately from the central stalk.
The pinnæ bear fan-shaped pinnules, which are attached to the stalk of
the leaf-division by very fine stalks. The margin of the pinnules is much
notched and veined. Where the frond is of a very large size they may be
divided three times.
[Illustration: Adiantum capillus-veneris. Enlarged view of back of
frond.]
In the case of a fertile frond the edges of the pinnules are turned back
in a very striking way. If we turn up the fold, it is possible to see the
sporangia arranged on the underside. Before the fertile leaf has reached
maturity the upper part of the fold has a whitish appearance; finally it
turns black.
The True Maidenhair Fern is more widely distributed than is generally
supposed in the South of England and in Ireland. It is a delicate
species, and, generally speaking, is restricted to those parts of the
kingdom where the winter is mild. It may be seen growing abundantly on
old quarries in Cornwall, as a rule quite out of reach. The Maidenhair
Fern is a fairly easy plant to grow in pots, though it likes a moist
atmosphere. Curiously enough, it is not so simple a plant to cultivate as
some of the exotic species. The True Maidenhair is an evergreen plant.
_Cryptogramme crispus._ The generic name of this fern is derived from two
Greek words, _kruptos_, “hidden,” and _gramme_, “a line,” having
reference to the fact that when mature the sori are arranged in lines
round the margins of the fronds. The specific name, _crispus_, is an apt
one, when the crisped or curled appearance of the barren fronds is
considered. In some books this species is called _Allosorus crispus_. The
Parsley Fern.
A very attractive species bearing both barren and fertile fronds. The
former in their general appearance certainly bear a resemblance to
Parsley. The Parsley Fern has a thick root-stock from which the fronds
grow up in tufts. The barren fronds, which will be considered first, grow
to the height of about six to nine inches. The stipes is somewhat longer
than the rachis, and it is of a whity-green colour. The outline of the
barren frond is roughly triangular, the apex of the leaf being rather
blunt. The pinnæ are placed alternately on either side of the main stem,
and these bear pinnules which have their margins deeply cut. In very
large specimens the fronds may be divided three times. The barren fronds
grow on the outside of the tuft. The fertile frond is somewhat taller
than the barren leaf, to which it bears a resemblance in its general
form. The pinnæ, of course, are very much restricted. At first the sori
are rounded, but as they mature they spread so as to form almost unbroken
lines round the margins of the pinnules. The sori have indusia, but this
is hidden by the margin of the pinnules, which are recurved.
There are few more local species than the Parsley Fern. The plant loves
to grow amongst rocks which are often scattered about on the slopes of
mountains. Its two chief strongholds seem to be the Snowdon district in
Wales and the mountainous parts of Cumberland. In some localities of
these districts the plant grows in the greatest abundance, happily often
out of the reach of the tourist. The Parsley Fern has also been recorded
in the West of England, and it occurs in Scotland. It is easily
cultivated, if the fact is borne in mind that it is a rock species
needing good drainage. It loses its bright, pretty colouring in a sunny
position. The Parsley Fern sends up its green fronds in the month of May,
and the fertile leaves follow soon after. The foliage disappears in the
winter.
CHAPTER VI
THE MALE FERN AND ITS RELATIVES
Apart from the Bracken Fern which, as we have seen, is abundant almost
everywhere, there are few ferns more common than certain of the leading
members of the sub-order Aspidieæ. The British representatives of this
sub-order include the important genus _Nephrodium_, of which the Male
Fern is the leading example. In addition we have the Shield Ferns
(_Aspidium_), and also some interesting species gathered together under
the genera _Woodsia_ and _Cystopteris_.
_Nephrodium Filix-mas._ The generic name is derived from the Greek
_nephros_, “a kidney,” this having reference to the kidney-shaped indusia
which is typical of the genus; _Filix-mas_, of course, is a name formed
of two Latin words, _filix_, “a fern,” and _mas_, “a male.” In some books
the species is called _Lastrea Filix-mas_, and _Aspidium Filix-mas_. The
Male Fern.
[Illustration: Nephrodium filix-mas. The Male Fern.]
One is almost tempted to follow the example of the early writers of
botanical works and to say that the plant is so well known that “it
needeth no description.” However, such a fine Fern, common though it be,
is certainly as worthy of a notice as any species within the covers of
this book. A very characteristic feature of the Male Fern is its stout
and sometimes very upright stem or caudex. In some plants this is at
times so large that it almost resembles a short trunk. It will readily be
seen that the leaves arise from the outside of the crown of the plant,
whilst at the base of the stalks occur the fibrous roots. Within the
circle of the developed leaves we may find the immature fronds; the least
advanced of these may not develop for three years. The crown of the
plant, as well as the stipes and the rachis, are more or less covered
with brown scales. The length of the fronds of the Male Fern vary
enormously. In a favourable situation the leaves may measure as much as
three feet or more, though an average example would be a good deal less
than this. A well-developed plant should show six or more finely
developed fronds arranged cup-fashion round the central stem. The shape
of the leaf of the Male Fern is roughly lanceolate, broadest in the
middle and tapering at each end. The frond is bi-pinnate, and the pinnæ
are long and taper to a fine point. The pinnules are rather blunt, and
frequently show serrated edges. The upper portion of the frond is
pinnatifid, and in many of the higher pinnæ it is only the pinnules
nearest to the rachis that are distinct.
Practically all the fronds are fertile, though the sori occur chiefly on
the upper portions of the leaves. The brown patches are to be found
arranged in a single line on either side of the central vein of the
pinnules. The sorus is circular and is covered with an indusium which is
notched or kidney-shaped. In the early days the indusium is of a lead
colour, but as the sporangia ripen underneath the brown colouring shows
through the thin covering. The foliage of the Male Fern is of a bright
green tint, changing to a duller shade as the leaves become older. Not
uncommonly the fronds last in good condition through a large part of the
winter when the season is mild.
It is now recognized that the Male Fern may be divided into three
sub-species. These are called _N. filix-mas_ (_true_), _N. pseudo-mas_,
and _N. propinqua_. The differences are not very obvious to the beginner,
but it is said that the first named is only partially deciduous—the
fronds lying prostrate during the winter. In the case of _N. pseudo-mas_,
the fronds are of a leathery nature, and the plant is practically
evergreen in sheltered positions. A well-established feature of _N.
propinqua_ is that the foliage completely dies away in the autumn.
The Male Fern is abundant in all parts of the United Kingdom where the
conditions are in any way suitable. Naturally it is of easy culture in
the garden. The new fronds, which are very pretty when they are
uncurling, put in an appearance in the month of April.
_Nephrodium Thelypteris._ The specific name of this plant is a compound
word derived from the Greek, meaning “ladyfern”; the title probably has
reference to the delicate growth of the species. The Fern is also called
_Lastrea Thelypteris_. The Marsh Buckler Fern.
This is a very attractive Fern, and perhaps the only British species
which frequently grows in water. The Marsh Buckler Fern has a creeping
rhizome from which arise the fronds at intervals; these are of two kinds,
barren and fertile. The barren fronds sometimes reach the length of four
feet, the stipes—which is slender and of a pale green colour—being about
equal to the leafy portion. The fertile fronds are usually shorter. In
both cases the outline of the fronds is the same, being lanceolate. In
each case, too, the pinnæ arranged alternately on either side of the
rachis are cut almost to the midrib. In the case of the fertile fronds
the pinnæ are perhaps a little more contracted; also the margins are
inclined to bend over in such a way as to protect the sori. The clusters
of sporangia are almost circular, and these are borne on the margins of
the lobes on the underside of the pinnæ. The clusters of the sporangia
are covered with small indusia which are slightly notched. The indusia
are soon thrown off when the spore cases start to develop.
The Marsh Buckler Fern is not uncommon, and in suitably moist positions
is often very abundant. It is, however, said to be rare in Scotland. The
species will not flourish in a garden unless something in the way of a
bog can be provided. The fronds appear in the spring and are cut down by
the first frost.
_Nephrodium oreopteris._ The specific name is connected with the Greek
word _oros_, “a mountain.” In some books this fern is also called _N.
montana_ and _Lastrea montana_. In certain districts, varieties of the
species are common. The Mountain Buckler Fern.
In certain respects this species bears a resemblance to the Male Fern.
The fronds spring from a tufted root-stock and their outline is
lanceolate; they are from one to four feet in length. The foliage of the
Mountain Buckler Fern is of a pale green colour. A distinctive feature is
the manner in which the frond of this Fern tapers to a point at both
ends; this is even more pronounced at the base than at the apex. In the
Male Fern any tapering at the base is of a very slight description. The
Mountain Buckler Fern is once pinnate, the pinnæ being continued almost
through the entire length of the stalk; this makes the stipes very short.
The pinnæ, which are generally placed opposite to one another, are cut
very deeply.
[Illustration: Nephrodium oreopteris. The Mountain Buckler Fern.]
The sori are much more abundant on the upper portion of the frond; we
shall find them on the back of the leaf along the margins of the lobes.
They are covered by a very slight indusium, which soon falls off. In the
Mountain Buckler Fern there are to be detected a number of tiny glands on
the back of the frond; these are responsible for rather a pleasant odour
when the foliage is passed through the hand.
[Illustration: Back of frond of a typical Nephrodium. Enlarged.]
The Mountain Buckler Fern grows on heaths, and it has been found in
almost all parts of the United Kingdom. In certain parts of Scotland it
is said to clothe the mountain sides with a wonderfully vigorous growth.
It is not, however, as its name seems to imply, strictly a mountain
species; for it often grows in lowland districts. In cultivation, the
species should be given a moist situation. The Mountain Buckler Fern dies
down in the winter and the new fronds appear in the spring.
_Nephrodium cristatum._ The specific name of this Fern simply means
“crested,” and has reference to the fringed border of the frond. It may
be pointed out, however, that there are not a few Ferns on which the name
_cristatum_ could with more reason have been bestowed. This species is
also called _Lastrea cristatum_. There are a number of forms of this
Fern.
This is a very handsome Fern, and it is a pity that it is not more
common. The fronds are somewhat oblong in outline and have a very narrow
appearance. The root-stock has a creeping habit and sends up tufts of
fronds at intervals. These are very erect, and usually measure between
one and three feet. The stipes is shorter than the leafy portion, and it
bears a few brown scales. The pinnæ are arranged alternately on the
rachis and these are not again divided, although they are very deeply
cut. The colour of the fronds is of a bright green.
The sori are borne in lines on either side of the mid-vein of the lobe.
These are covered at first by an indusium which is notched after the
manner of that of the Buckler Ferns.
The Crested Buckler Fern is very rare, though it is found in a few
localities—chiefly in the North of England. As a rule it occurs on boggy
heaths, and if these conditions can be imitated in the garden, the Fern
grows freely. The fronds are soon cut down by the autumn frosts, and the
new growth does not appear until May.
_Nephrodium spinulosum._ The specific name means that the plant has
little spines. This Fern is associated with other forms, and in some
quarters has not been regarded as a definite species at all. Some of the
varieties, or, as some authorities say, actually distinct species, with
which it is associated have been called _N. dilatatum_ and _N.
uliginosa_. It may be mentioned that some botanists consider _N.
dilatatum_ to be the most important of the three forms. The chief points
about _N. dilatatum_ are the very dark green fronds which are extremely
broad at the base; these spring from a massive caudex. The whole plant
has a very robust appearance, and it is exceedingly common. Providing the
situation is shady this Fern is not particular as to its place of growth.
In the same way the preceding species _N. cristatum_ is regarded by some
as a doubtful species. On this account the beginner will find _N.
spinulosum_ rather difficult to identify, and he must be prepared for
departures from the present type which is here described. The Prickly
Buckler Fern.
[Illustration: Nephrodium dilatatum.]
The frond of this species rises from an erect root-stock. The length of
the leaves varies from one to three feet, and the stipes is usually about
a third of this in measurement. The fronds are triangular in outline, and
it is seen that the pinnules nearest to the rachis are considerably
larger than the upper ones. This gives a very tapering appearance to the
pinnæ. The borders of the pinnules are deeply cut, and the lobes are
adorned with tiny points which give a somewhat prickly appearance. The
lobes are most prominent on the lowest pinnules, and are also far more
pronounced on the lowest pinnæ than they are on the upper divisions of
the frond.
The sori are placed on small veins which grow outwards from the midrib of
the pinnule. These are covered with kidney-shaped indusia. As has been
indicated, the Prickly Buckler Fern varies enormously, both in size and
in almost every other particular.
The Prickly Buckler Fern is not uncommon in parts of England, and is to
be found in damp woods, especially by the sides of streams. It seems to
be less abundant in other parts of the kingdom. It is of easy culture in
the garden. The Prickly Buckler Fern retains its fronds through the
winter.
_Nephrodium æmulum._ Here the specific name is taken from a Latin word
meaning “comparable with”; the reference is to the similarity of the
species of _N. spinulosum_. Some botanists have considered that _N.
æmulum_ is merely a variety of _N. spinulosum_, though the species seems
to be quite distinct. The species is also called _Lastrea æmula_; _L.
fœniscii_ and _L. recurva_. The Hay Scented or Triangular Buckler Fern.
A very characteristic feature of this species are the upturned margins of
the fronds. This makes the leaf look as if it was curled, and at the same
time renders the upper surface of the frond concave. The outline of the
fronds is roughly triangular, being widest at the base. The fronds are
about one or two feet in length, and the stipes is about equal to the
leafy portion. The pinnæ are arranged either in pairs or alternately on
either side of the stalk. These are divided into pinnules which, in some
cases, towards their bases are again divided. The fronds are of an
exceptionally bright green colour, and when bruised give out a pleasant
odour not unlike that of new hay. This is due to the secretions of small
glands which are to be found on the undersides of the fronds.
The sori on the backs of the fronds are arranged in lines on either side
of the mid-veins of the lobes. These are covered with kidney-shaped
indusia.
The Hay Scented Buckler Fern cannot be said to be common, although it has
a wide distribution and may turn up in unexpected places. It is more
abundant in the West of England and in Ireland than elsewhere. It only
flourishes in damp places, and this point must be borne in mind when
planting it in the garden. The Hay Scented Buckler Fern is an evergreen
species.
_Nephrodium rigidum._ The specific name—Latin for “stiff”—is evidently
bestowed on the plant on account of its erect habit of growth. The
species is also called _Lastrea rigida_. The Rigid Buckler Fern.
This species is quite the rarest of all the Buckler Ferns. The plant has
a thickish root-stock from which arise the fronds, usually about a foot
in length. The stipes is, as a rule, about half the length of the entire
leaf; the bare portion of the stalk is thickly covered with brown scales.
The outline of the frond is somewhat variable; on occasion, examples may
be found with a lanceolate outline, whilst others may be distinctly
triangular in shape. The frond is bi-pinnate, the pinnate being placed
rather irregularly on either side of the rachis. The pinnules are blunt
and somewhat oblong in shape; they have serrated edges, but do not bear
any spines.
The sori are placed on either side of the vein in the middle of the
pinnules. These are covered in their early stages with kidney-shaped
indusia. Sometimes this frond has a slight fragrance when it is bruised.
The Rigid Buckler Fern is really a mountain species, and generally grows
at an elevation of more than a thousand feet above sea-level. It is
fairly common in parts of Yorkshire and in some of the north-western
counties of England, otherwise it is a real rarity. It is not difficult
to grow in the garden, but as it flourishes best in a limestone soil it
is a good plan to mix bits of this rock up with the soil which is used.
The new fronds appear in May and die down during the winter.
_Polystichum (Aspidium) lonchitis._ Here the generic name is based on two
Greek words, _polys_, “many,” _stichos_, “order”; the specific name is
also derived from another Greek word—_lonche_, “a spear,” this referring
to the narrow spear-like appearance of the fronds. The Holly Fern.
This species, on account of its regular habit of growth and generally
stiff appearance, is an easy one to identify. The fronds arise from a
tufted root-stock, and in average specimens would be about nine inches in
length. This might be greater or less, according to the conditions under
which the particular plant was living. The shape of the fronds is
narrowly lanceolate, and there is a very short stipes which is thickly
covered with scales. The leaves of the Holly Fern are once pinnate, the
pinnæ being ovate and having a curious ear-shaped enlargement at their
bases on the upward side. The edges of the pinnæ are adorned with a
number of sharp teeth, and this gives a singular spiny appearance to the
whole plant. On this account the Fern has probably received its popular
name of Holly Fern. The colour of the foliage is of a very pretty bright
green tint.
[Illustration: Polystichum lonchitis. The Holly Fern.]
The Holly Fern, as indeed are all the species of _Polystichum_, is very
distinct from a _Nephrodium_ in the matter of its indusium. This is quite
circular, and has no notch; moreover, it is attached to the pinnules by a
short stalk in the centre. Thus it is proper to describe the shape of the
indusium as peltate. The sori are chiefly confined to the upper portion
of the back of the frond, and are situated on either side of the midrib
of the pinnæ. After the falling away of the indusia the sori tend to
spread, so that they may finally cover almost the whole of the back of
the fertile pinnæ.
The Holly Fern is essentially a plant of the mountains, and it is often
found growing in the most exposed situations. It is not common in
England, though it has been found in a few localities in the north. The
species has a much wider distribution in Scotland. The Holly Fern is
evergreen in habit, and its stiff fronds seem to be able to withstand the
severest frost. The plant is rather a difficult one to grow, though if it
can be given a rock crevice it will sometimes settle down happily in the
garden. The foliage of the Holly Fern lasts through the year.
_Polystichum (Aspidium) aculeatum._ In this case the specific name is a
Latin term simply meaning “provided with prickles”—an allusion to the
fact that the fronds are adorned with spines. The Hard Prickly Shield
Fern.
This species is very distinct in its general appearance from the Holly
Fern, though it can at once be seen to be a Shield Fern by the unnotched
indusia which cover the sori. The fronds may be as much as two feet in
height, or even a little more, and these rise from a tufted root-stock.
As a rule the stipes is very much shorter than the leafy portion, and
both it and the rachis are thickly covered with scales. The outline of
the frond is lanceolate, and the colour of the foliage is dark green. A
pretty glossy effect is noticeable on the upper surface. The frond of the
Hard Prickly Shield Fern is twice divided, and the pinnæ are arranged
alternately on either side of the rachis. A distinctive point about this
species is that the upper pinnules at the base of each pinna is larger in
all ways than the other pinnules. The pinnules are provided with sharp
teeth, and it should be noted that they have nothing very decided in the
way of stalks. Actually they are what botanists call decurrent—that is,
tending to run together at the base. In some varieties of this species
the tendency is more marked than in others.
The sori are placed on either side of the mid-veins of the pinnules, and
these are usually confined to about half the upper portion of the back of
the frond.
The Hard Prickly Shield Fern is very widely distributed in England, and
it is to be looked for in shady woods. It is an exceedingly easy plant to
grow, and thrives even in town gardens. The plant is evergreen in habit.
_Polystichum (Aspidium) angulare._ It is not regarded by some botanists
as an established species, but is thought to be a variety of _A.
aculeatum_. However, there are certain differences which appear to be
specific. The Soft Prickly Shield Fern.
As in the Hard Prickly Shield Fern, we find a tufted root-stock from
which grow lanceolate fronds. We notice the same short stipes and the
narrow pinnæ on the leafy portion tapering to a point. In this species it
is said that the pinnules at the base are more nearly equal in size than
is the case with _A. aculeatum_. The pinnules are also more definitely
stalked in the former than in the latter. In the case of the Soft Prickly
Shield Fern, it is noticeable that all parts of the stalk of the
frond—both stipes and rachis, and even the rachides—are covered with
brown scales. It is said, too, that the droop of the fronds is more
pronounced in the Soft Prickly Shield Fern than in the Hard Prickly
Shield Fern.
The arrangement of the sori is similar in both species.
The Soft Prickly Shield Fern has been found widely distributed in England
and Ireland, though it is not so common in other parts of the United
Kingdom. It is easily cultivated, and is evergreen in habit.
_Woodsia hyperborea._ The generic name of this species commemorates the
botanist, Mr. Joseph Woods; the specific name is taken from two Greek
words—_hyper_, “beyond,” and _Boreas_, “the north wind,” without doubt a
reference to the fact that the species extends to the Arctic regions. The
plant is also called _Woodsia alpina_. The Alpine Woodsia.
This is a very pretty little Fern. The tiny fronds, which are not more
than two or three inches in length, spring from a tufted root-stock. The
stipes is rather short and bears a few brown scales. The outline of the
frond is oblong, and the leaf tapers slightly towards the base as well as
at the apex. The fronds are once pinnate, and the pinnæ, which are lobed,
are arranged in rather an irregular fashion on either side of the
leaf-stalk. A curious feature of the Alpine Woodsia is that the fronds
are jointed just above their connexion with the root-stock. When the
leaves die the stalks break away at this point and leave the bases
behind.
When the back of the frond is examined it is evident that we have here a
very distinctive feature. The patches of spore cases are covered with a
very thin indusium, and as time goes on this splits into divisions which
resemble a number of hairs. The fronds are of rather a stout texture for
so small a Fern, and in all parts show an inclination to be hairy.
The Alpine Woodsia is a very rare Fern, and there are only a few recorded
localities of it in England and Wales. It makes its home on moist rocks
on the slopes of high mountains. This little Fern is fairly easily
cultivated. The fronds disappear in the winter.
[Illustration: Woodsia ilvensis. The Oblong Woodsia.]
_Woodsia ilvensis._ The specific name refers to the island of Elba
(Ilva), where this plant was first of all discovered. In some quarters
this plant is held to be merely a variety of _W. hyperborea_. The Oblong
Woodsia.
The fronds of this Fern rise from a tufted root-stock. The stipes is
short, but the frond as a whole is larger than that of the Alpine
Woodsia, and may be as much as six inches in length. The outline of the
fronds is oblong, tapering towards the base and at the apex. Over the
whole frond, both on the upper and the lower side, is a covering of fine
hairs. Usually the hairiness of the Oblong Woodsia is very pronounced.
The covering is so thick on the underside that it is rather difficult to
discover the sori. These have the same curious divided indusia to be
observed in the Alpine Woodsia.
The Oblong Woodsia is a very rare Fern, only to be found in mountainous
districts. It has been reported from a few localities in England and also
occurs in Scotland, usually in almost inaccessible places. The fronds die
down in the winter and break away from the stem just at the crown of the
root-stock.
_Cystopteris fragilis._ The generic name of this Fern is formed of the
two Greek words _kystos_, “a bladder,” and _pteris_, “a fern.” The
specific name is, of course, a Latin word which means “easily broken.”
The Brittle Bladder Fern.
This is one of the most beautiful of all our native Ferns. From a tufted
root-stock which is clad with pale brown scales the fronds arise; these
are about six or eight inches in length and are lanceolate in outline.
This Fern has a habit of spreading in such a way, that each plant may
have several of the tufted crowns from each of which arise a cluster of
fronds. These are sometimes once, and on other occasions, twice pinnate.
The pinnæ are about an inch in length, and where there are pinnules these
are toothed.
We shall find the sori on veins which run from the mid-vein of the
pinnules. The spore patches are rounded and are covered with a curious
indusium, with an inflated appearance towards the centre. It is from the
resemblance of this indusium to a bladder that the plant has received its
popular name. With the disappearance of the indusia the sori tend to
spread over the whole surface of the back of the frond. The general
appearance of the Brittle Bladder Fern is of a delicate nature and it has
a very distinctive appearance.
[Illustration: Cystopteris fragilis. The Brittle Bladder Fern.]
Properly speaking, the Brittle Bladder Fern is a mountain species, though
it sometimes occurs on old walls or in rocky clefts which are not very
elevated. The species is widely distributed in all parts of Great
Britain, though in frequented districts it is soon exterminated. The
Brittle Bladder Fern does not seem to grow very well in the open rockery,
though it is fairly easy to cultivate in pots. The fronds die down at the
approach of winter. There are a certain number of varieties.
_Cystopteris montana._ Here the specific name is formed from the Latin
word _mons_, “a mountain.” The Mountain Bladder Fern.
This is the only other recognized species of Bladder Fern to be found in
the United Kingdom. The species has a slender creeping underground stem
from which arise the delicate fronds. These are usually about four to
eight inches in length, and the stipes is considerably longer than the
leafy portion. The design of the frond is rather like that of the
three-branched Polypody, this being due to the fact that the lowest pair
of pinnæ is much larger than any of the others.
The general outline of the fronds is wedge-shaped, and these are very
finely divided. Indeed in a well-developed leaf the fronds may be three
or even four times pinnate. The pinnules themselves are also deeply cut.
It will be noticed that the lower portion of the frond is always more
freely divided than the upper part; a common characteristic in Ferns.
The sori are very freely scattered on the lobes or pinnules at the back
of the frond, and these are covered with the curious hooded indusia which
were noticed in the last species.
The Mountain Bladder Fern is perhaps the rarest of all our native
species. It is at home in mountainous districts, and seems only to have
been noticed in a few localities in Wales and Scotland. Probably it would
be seen more often were it not that it grows in positions which are not
of easy access. It should be given the same treatment in the garden as
that recommended for the Brittle Bladder Fern. The fronds disappear in
the winter.
In some books a species is given, known as _Cystopteris alpina_ or
_regia_. The plant nearly resembles _Cystopteris fragilis_, although it
is somewhat smaller. This is a very doubtful native, as it seems only to
have been recorded in one or two localities where it may have been
naturalized.
CHAPTER VII
THE LADY FERN AND THE SPLEENWORTS
The sub-family Asplenieæ has a large number of representatives in the
United Kingdom. There is much division of opinion as to the real place of
the Lady Fern. Many botanists consider that the species is a true
_Asplenium_. Others regard it as the solitary British representative of
the genus _Athyrium_. All Fern growers support the latter view. Some of
the small Spleenworts are quite common.
_Athyrium_ or _Asplenium Filix-fæmina_. The generic name of the
Spleenworts is derived from the Greek word _splene_, “the spleen,” this
having reference to the fact that in the old days a medicine derived from
the leaves was held to be a remedy for diseases of the spleen. The
specific name is simply a combination of two Latin words—_Filix_, “a
fern,” and _fæmina_, “a woman,”—that is, “Lady Fern,” a name no doubt
given on account of the elegant appearance of this species, particularly
when it is compared with the Male Fern (N. _Filix-mas_). The Lady Fern.
[Illustration: Athyrium filix-fæmina. The Lady Fern.]
Although it is altogether more fragile in appearance, the growth of the
Lady Fern bears a resemblance to that of the Male Fern. We notice the
same tall fronds rising from a stout root-stock covered with brown
scales. In a favourable situation, such as a damp hedge, these fronds may
grow to the length of four feet, or even more. They are of a beautiful
pale green colour, and being of a thin texture soon disappear at the
approach of winter. The stipes is usually about one-third of the whole
leaf, and is sometimes of a brownish colour. The stalk is remarkable for
its brittle nature. The outline of the fronds is lanceolate, and they
taper very decidedly towards the base as well as at the tip. The leaves
of the Lady Fern are bi-pinnate. The pinnæ are placed either in pairs, or
alternately, on opposite sides of the rachis, and these in turn are
divided into toothed pinnules. In the case of both the pinnæ and the
pinnules the distinctiveness is lost towards the upper portion.
The sori are very abundant, but as these are small they should be
carefully examined. They occur about midway between the central vein of
the pinnule and the margin of the leaf. The indusium is not clearly
linear, being more in the shape of a horseshoe, but this character can
only be recognized before the delicate covering has started to shrivel.
There are a huge number of variations of the Lady Fern, but many bear a
more or less striking resemblance to the type.
Happily the Lady Fern is common in many parts of the United Kingdom.
Often it is to be found growing surprisingly near to towns, though its
pretty green foliage makes a strong appeal to the eye of those vandals
who go about uprooting every fern which they see. It is of easy culture
in the garden. The fronds of the Lady Fern develop in the spring of the
year.
_Asplenium septentrionale._ The specific name means “northern,” and this
has reference to the fact that the species is more abundant in the north
than in the south. The Forked Spleenwort.
The fronds of this Fern are of a thick leathery nature, but they are
rarely more than about two inches in length. As they are produced in
thick tufts, the individual plants will often cover a good deal of space,
considering the diminutive nature of the plant as a whole. The stipes is
considerably longer than the leafy portion of the frond; this latter is
of a very simple nature, being composed of two or three blades which fork
out something on the lines of a stag’s horn. The plant is quite unlike
any other British Fern, although its foliage bears a singular resemblance
to that of the Buck’s Horn Plantain (_Plantago coronopus_), a common
enough weed, especially on waste patches near to the sea.
On the underside of the narrow blades are produced the sori; these are
present in the form of lines on either side of the mid-veins. At first
they are covered with scale-like indusia, but as the sporangia ripen the
protecting shield is thrown aside. Finally, the capsules spread out so as
to cover almost the whole of the underside of the blade.
The Forked Spleenwort finds its home in the fissures of rocks and in the
crevices of old walls. It is, however, a rarity, less uncommon in the
North than in the South of England. Now and again it has been recorded in
great abundance in a particular spot, and it is difficult to understand
why the species is not more wide-spread in its distribution. The Forked
Spleenwort can be grown in gardens if suitable rock crevices are
provided. The plant is an evergreen species.
_Asplenium germanicum._ It is uncertain what is the derivation of the
specific name _germanicum_; in some quarters it has been said that the
name was given owing to the fact that the Fern is a very popular one in
Germany, though whether this is a true explanation cannot be stated with
certainty. The Alternate-leaved Spleenwort.
This species is somewhat larger than the last-named, though it is hardly
so striking in appearance, owing to the comparatively small number of
fronds which are produced. These will, as a rule, be about four or five
inches in height, and they arise from a tufted root-stock. The stipes is
about the same length as the leafy portion of the frond. The rachis bears
alternately curious wedge-shaped pinnæ. At the broad end these pinnæ are
toothed, and these segments are more pronounced on the lower than on the
upper pinnæ. The fronds are of a fairly tough texture.
On the backs of the pinnæ we shall find the sori, two or three lines of
the collections of sporangia being present on each division of the frond.
At first these are covered with an indusium, but as the capsules ripen
this is thrown away and the clusters join together in one mass.
The Alternate-leaved Spleenwort is very rare. It is, however, known to
occur in a few rocky localities in England and Scotland. Probably it is
often overlooked by the few people who visit the more inaccessible parts.
It has proved to be rather a difficult subject to grow, and it has a most
annoying habit of dying off suddenly, even when given a great amount of
care. Probably the real trouble is that it is given too much water; good
drainage would go a long way to meet the difficulty. The fronds of the
Alternate-leaved Spleenwort sometimes survive the winter.
_Asplenium ruta-muraria._ In this case the specific name simply means
“wall rue,” and refers to the resemblance which the Fern bears to the
Common Rue (_Ruta graveolens_). The Wall Rue.
[Illustration: Asplenium ruta-muraria. The Rue-leaved Spleenwort.]
A very charming little species, with which most people who take the least
interest in Ferns are probably familiar. In reality this plant is a rock
Fern, but it often finds a congenial home on old walls. The Wall Rue has
a tufted root-stock which is furnished with a quantity of fibrous roots;
these often force their way for a considerable distance into the
crevices. From the root-stock arise a number of little fronds; where the
situation is dry, and the battle for existence is a hard one, these may
not be more than a couple of inches in length. In damp situations the
fronds might measure three times as much. Where the examples are dwarfed
the stipes will be about the same length as the leafy portion, but in a
well-developed instance it will be much longer. The colour of the fronds
is of a dark green colour, and these are of a somewhat leathery nature.
In a fair-sized example the frond is twice pinnate, the pinnæ are
definitely stalked, and the pinnules are roughly wedge-shaped, being
somewhat toothed at the lip. The Wall Rue is excessively variable, and in
exposed places it is possible to find plants bearing fronds which are
only divided once, the pinnæ being segmented.
[Illustration: Back of frond of Asplenium ruta-muraria. Enlarged.]
The sori are in the form of lines which branch out from the lower part of
the pinnule in a fan-shaped manner. The indusium disappears as soon as
the sporangia become mature, and eventually the sori may spread over the
whole of the back of the pinna or pinnule.
The Wall Rue is really a very common Fern, but it is often overlooked
when hiding in the dark crevice of some old wall. The plant has a
wonderful habit of adapting itself to dry conditions. It is of easy
cultivation if it can be given an open and well-drained situation. The
Wall Rue is an evergreen plant.
_Asplenium adiantum-nigrum._ In this case the specific name is formed of
two words, the first of which belongs to the true Maidenhair Fern. As has
already been explained, it comes from a Greek word which means
“unwetted,” a reference to the fact that the fronds do not become damp
when it rains. The word _nigrum_, of course, simply means black, and is
obviously an allusion to the colour of the leaf-stalks of this Fern. The
Black Maidenhair Spleenwort.
A very pretty Fern, which in some ways is to be regarded as the most
attractive of all the Spleenworts. The species varies a good deal
according to the situation in which it is growing. Thus in dry
hedge-banks it will be a comparatively small Fern, whilst when growing in
damper situations—such as by the side of a waterfall—it will be very much
larger. The root-stock is thick and is densely covered with scales, and
from it arise the leaf-stalks, which are black towards the base. The
stipes is usually about the same length as the leafy portion. In the
varying forms the fronds range from about four inches to a foot, or even
more, in length. In the smaller examples the fronds are twice pinnate,
whilst the larger leaves may be thrice pinnate. The general outline of
the frond is triangular, and the pinnæ, which are arranged alternately on
either side of the rachis, are somewhat similar in outline. The pinnules
are shaped like wedges and have toothed lobes.
If we turn up a frond of the Black Maidenhair Spleenwort we shall
discover the sori situated on veins which issue from the mid-veins of the
pinnules. In their early days these clusters are distinctly in the form
of lines, but after the throwing off of the indusia they rapidly mature
and spread to such an extent that the whole of the under-surface of the
pinnule is covered. Often an entire frond appears to be completely brown
on its underside.
The Black Maidenhair Spleenwort is an exceedingly common Fern. It occurs
in almost all parts of the United Kingdom, although, of course, near
towns it is usually rooted up. The species is of very simple culture and
will be quite happy on an ordinary rockery. The Black Maidenhair
Spleenwort retains its fronds throughout the winter.
_Asplenium lanceolatum._ The specific name has reference to the fact that
the outline of the frond is lanceolate. The Lanceolate Spleenwort.
This is a species which in its early days is sometimes confused with the
Black Maidenhair Spleenwort. The fronds, which are lanceolate in outline
and about four inches to a foot in length, arise from a tufted
root-stock; the stipes is usually about a third of the frond. The colour
of the stipes, and also part of the rachis, is bright brown, and this
contrasts finely with the handsome green of the leafy portion. The actual
length of the fronds will vary to a considerable extent, this depending
upon the amount of moisture available. The design of the frond, when it
is developed, shows by its lanceolate outline a marked feature which
distinguishes it from the triangular outline to be seen in the case of
the Black Maidenhair Fern. The frond is twice pinnate, and as a rule the
pinnæ are opposite; these are roughly egg-shaped in form. The pinnules
have serrated margins.
The sori are placed on veins which branch out from the mid-veins of the
pinnules. At first the collections of sporangia are long and narrow, and
covered with a white indusium. As the capsules mature the sori spread out
over the under-surface of the frond.
The Lanceolate Spleenwort is usually met with near to the sea or in
mountainous districts. It is rather local, although it sometimes occurs
in great plenty on damp rocks. It is said not to occur in Scotland. In a
suitable rocky corner there is no reason why the Lanceolate Spleenwort
should not be grown in a garden. The situation should be well drained,
but a sufficiency of water is needed. The Lanceolate Spleenwort remains
green throughout the winter.
_Asplenium marinum._ The specific name _marinum_ has, of course,
reference to the fact that the Fern is to be found near the sea. The Sea
Spleenwort.
This is an interesting and a most beautiful species, often growing
abundantly from the roof-crevices of caves on the coast. The root-stock
of this plant is stout, and from it are produced a large number of fine
black roots which penetrate into the rocky fissures. The fronds are, as a
rule, four or five inches in length, though in favourable situations they
may be very much longer. The stipes is somewhat short, hardly ever more
than a third of the length of the frond, and sometimes less than this. In
most cases the stipes is of a purple colour, and the leafy portion of the
frond is of an exceptionally fine green shade. The leaves are freely
produced in tufts and are roughly lanceolate in outline. The fronds of
the Sea Spleenwort are only once pinnate, the pinnæ—which are usually
about an inch in length—being, as a rule, oblong in outline. They are,
however, decidedly variable in form, some being egg-shaped. A curious
feature of the pinnæ is that they are unequal in shape at the base, the
lower part appearing to have been cut off whilst the upper portion is
greatly enlarged. Between the lower pinnæ the rachis is winged, but this
feature disappears at the tip of the frond where the pinnæ run together.
[Illustration: Asplenium marinum. The Sea Spleenwort.]
The sori are to be found on the underside of the pinnæ, arranged in lines
on either side of the mid-veins. During the early days the cluster of
sporangia is covered with very distinct indusia, but as the capsules
ripen, these disappear.
The Sea Spleenwort is hardly ever found at a great distance from the sea.
It is most common on the coast of southern and western England, sometimes
appearing in great abundance in rocky caves. The species also occurs in
other parts of the United Kingdom where there is a rocky coastline.
Happily it often grows in inaccessible places, and even where the plant
can be reached with ease it is extremely difficult to tear the root-stock
from its crevice. It seems to be almost impossible to grow the Sea
Spleenwort in the open garden, although it is readily cultivated under
glass. The species is evergreen in habit, though the foliage will not
stand frost.
_Asplenium ceterach._ The specific name is considered to be a corruption
of _Chetherak_, a name given to this Fern by early medical writers. In
some books the species is called _Ceterach officinarum_. The Scaly
Spleenwort.
This is the most distinctive of all the Spleenworts. The root-stock of
the plant is tufted and scaly, and from this are sent down dense masses
of roots which penetrate into the remote recesses of the wall or rock
crevice where the Fern has made its home. The fronds vary greatly in
length, and in a very exposed situation may not be more than an inch or
so; in a sheltered and moist place they will be two or three times this
size. The outline of the fronds is lanceolate. Strictly speaking, the
fronds of the Scaly Spleenwort are pinnatifid, the leaf being designed
with rounded lobes and deeply cut intervals. When held lengthways an idea
is obtained of the wonderfully regular manner in which the cutting-out of
the lobes has been devised. The segments of the fronds occur alternately
on the rachis.
At first glance it is not an easy matter to discover the sori, for the
back of the frond of this Fern is completely covered with brown scales;
these are, however, white in the early days of the leaf.
By removing the scales it is possible to see the groupings of the sori;
these are arranged in the form of rough lines. There is no very clear
indication of an indusium, and indeed when one considers the protective
scales this hardly seems to be necessary. It is generally considered that
the scales on this Fern act in a protective manner during the long spells
of dry weather. In such a condition the fronds of the Scaly Spleenwort
appear to be trying to roll right up, whilst the lobes close in towards
each other. To all appearance the plant is dead. It soon revives,
however, after a good shower of rain.
The Scaly Spleenwort is to be looked for in limestone districts, where it
occurs on old walls or amongst rocks, often in great abundance. It is
said to be less common in Scotland than in other parts of the United
Kingdom. Under cultivation the Scaly Spleenwort often comes to grief
through excessive moisture; it is most happy in a crevice on a rockery.
The Scaly Spleenwort is an evergreen plant.
_Asplenium trichomanes._ The specific name is probably formed of two
Greek words—_thrix_, “a hair,” and _manos_, “soft.” This is doubtless a
reference to the hair-like nature of the leaf-stalks. The Maidenhair
Spleenwort.
This is a very familiar Spleenwort, not infrequently sold as the English
Maidenhair. The plant has a stoutish root-stock, from which grow a
quantity of fine roots; these often penetrate for a long way into the
crevices of the rocks, or between the building materials of an old wall.
The length of the fronds varies from a few inches to nearly a foot. The
stipes is very short and is extremely brittle. On either side of the
rachis, which is of a deep purple colour, the pinnæ are produced. These
are borne on a very short stalk and are of an oval shape, being about
half an inch in length. The margins of the pinnæ are occasionally
slightly toothed. As a rule, the pinnæ are set in opposite pairs on
either side of the rachis. A curious feature of the leaf-stalks of the
Maidenhair Spleenwort is that they do not decay at once when the pinnæ
fall off. Thus it is often possible to find thick bunches of them on the
root-stock looking like so much dark hair.
[Illustration: Asplenium trichomanes. The Maidenhair Spleenwort.]
The sori are placed in the form of lines on veins which branch from the
mid-vein of the pinnæ. In the early days the clusters of spore capsules
are covered with indusia; as the capsules mature these are thrown off,
and finally the sori may spread over the back of the pinnæ.
The Maidenhair Spleenwort is an exceedingly common Fern in many parts of
the United Kingdom. It is often found on old walls in great abundance.
Happily it is not an easy plant to exterminate; for, owing to the long
roots already mentioned, it is a difficult matter to dislodge a plant
from its crevice. In the garden the Maidenhair Spleenwort is perfectly
happy on a rock ledge; it should not be given a large amount of moisture.
The Maidenhair Spleenwort is an evergreen species.
_Asplenium viride._ Here the specific name is formed of the Latin word
_viride_, “green,” obviously a reference to the bright colour of the
fronds. The Green Spleenwort.
In some respects this species resembles the Maidenhair Spleenwort, though
there are certain important distinctions. In the first place, there is
the bright green colour of the whole plant; this is very different from
the dull shade of the Maidenhair Spleenwort. The Green Spleenwort also
grows in damp situations, and would not be at all happy on the top of a
wall. Most distinctive of all, the Green Spleenwort has a bright green
rachis to its fronds, although the stipes has a tendency to be purple in
colour. In other respects the two plants are very similar. We notice the
same narrow frond with the rounded pinnæ set on either side of the
rachis, sometimes in pairs and sometimes in alternation. The margins of
the pinnæ are inclined to be notched.
The sori are narrow, and when young are covered with an indusium. It is
said that even when ripe the sporangia hardly ever spread over the entire
surface of the pinnæ, as is to be seen in the case of the Maidenhair
Spleenwort.
[Illustration: Asplenium viride. The Green Spleenwort.]
The Green Spleenwort is a much rarer species than the Maidenhair
Spleenwort. It grows in wild and often mountainous situations in various
parts of the United Kingdom. As has already been indicated, it likes
rather damp situations, and is to be seen at its best in moist places.
The Green Spleenwort is rather a difficult plant to grow in the garden,
and it is happiest of all in a humid greenhouse—unless, of course, a very
favourable situation can be found out of doors. The fronds of the Green
Spleenwort generally last through the winter.
_Scolopendrium vulgare._ In this case the generic name is derived from
_scolopendra_, the Latin name for a “centipede”; this has reference to
the supposed resemblance of the lines of spore cases to the legs of a
centipede. The specific name is, of course, simply Latin for “common.”
The Hartstongue.
[Illustration: Scolopendrium vulgare. The Hartstongue.]
This is certainly one of the most familiar of all British ferns. Almost
alone amongst the well-known species, the plant has an uncut frond. The
leaves rise from a tufted root-stock which generally stands well above
the level of the ground. The length of the fronds varies considerably,
and in a mature plant which has found a damp corner these are sometimes
two or three feet in measurement. Where the plant has found a home on a
dry wall, however, it may be a very diminutive affair. As a rule, the
stipes will be about one-third of the whole frond, the leafy portion
being long and tongue-shaped. At the tip the frond ends in a point,
whilst towards the middle the leaf swells out again, narrowing once more
towards the base and finally expanding again into a couple of ear-shaped
projections. The rachis of the Hartstongue Fern is a very prominent
feature, and at the back of the leaf appears in the form of a ridge.
[Illustration: The sori on the back of a Hartstongue frond.]
From the rachis arise veins which run out to the borders of the frond,
and parallel to these are the linear sori. Although at first sight this
is not very apparent, the brown lines are composed of two sori which
practically join together. The pairs of sori are covered with pairs of
indusia which, on the maturity of the sporangia, open out opposite to
each other. As a rule the sori are most plentiful on the upper portion of
the frond of the Hartstongue. There are an immense number of varieties of
the Hartstongue, some of which are familiar garden subjects. In a wild
state it is not an uncommon thing to find fronds which are abnormal, and
some of these show a greater or less tendency to develop fronds which are
branched.
The Hartstongue is an excessively common Fern, often occurring in the
greatest abundance. It is said to be less frequent in Scotland than in
other parts of the United Kingdom. Naturally it is of the simplest
culture in the garden.
There is much division of opinion as to the position of the Fern, which
we must now consider. In some quarters it has been given a place among
the Spleenworts, but many authorities consider that the Hard Fern is the
solitary British representative of its class.
_Blechnum spicant._ In this case the generic name is derived from a Greek
word _blechnon_, a name for a Fern. The specific name, _spicant_, is from
the Latin _spica_, “a point.” The application of the name is realized
when the sharply-pointed pinnæ are examined. The species is in some books
called _Lomaria spicant_ and _Blechnum boreale_. The Hard Fern.
This species has a rather thin root-stock, from which arise large
quantities of wiry roots. From the crown the two kinds of fronds are sent
up. We may first consider the barren fronds: these vary according to the
conditions under which the plant is growing, and range from a few inches
up to one or two feet in height. The stipes is very short and it is of a
brownish colour, with a few scales. The leafy part of the frond is
narrowly lanceolate, tapering slightly at the point but more decidedly at
the base. On either side of the rachis, which is green, are arranged the
pinnæ; these are not opposite, but are in alternation. The pinnæ are
narrow and oblong, and at the tip the frond tends to become pinnatifid,
whilst at the base the pinnæ are little more than rounded lobes. The
frond has been not inaptly likened to a double comb. The fertile frond
has much the same outline as the barren one; it is, however, easily
distinguished by its greater length and the extremely narrow pinnæ. These
fertile fronds arise from the centre of the clump and are at their best
about the month of June. They are very erect in their growth. The
sporangia are borne along the margins of the pinnæ of the fertile fronds.
The borders of the pinnæ seem to curl over and protect the sporangia; by
a close examination it is easy to discover the independent indusia. When
the spore capsules ripen they spread so that the whole of the underside
of the pinnæ is covered. The texture of both the barren and the fertile
fronds of the Hard Fern is very leathery.
The Hard Fern is, of course, a very common species, to be found all over
the United Kingdom. The plant is of a simple culture and is evergreen in
habit.
CHAPTER VIII
THE POLYPODIES
There must be very few people, indeed, who are not familiar with the
leading British representatives of the sub-family _Polypodieæ_. It is
difficult, indeed, to make a journey in any part of the country without
sooner or later coming across some plants of the Common Polypody. Some
other species of the genus _Polypodium_ are not uncommon in certain parts
of the country.
_Polypodium vulgare._ Here the generic name is derived from two Greek
words—_polys_, “many,” and _pous_, “a foot.” This has been given to the
plant on account of the fact that the creeping and branching rhizomes
from which the fronds arise are in some way suggestive of feet. The
specific name, of course, means “common.” The Common Polypody.
This species has a creeping root-stock which in its young days is covered
with brown scales. From the underside there grow masses of fibrous roots,
which often spread for a considerable distance. The rhizome may be very
much branched, and from it alternately on either side arise the fronds.
These may be quite short—about five or six inches—or, on the other hand,
they may be as much as one or two feet in length. The stipes is usually
about the same length as the leafy portion of the frond and is of a plain
green colour. The general outline of the leafy part of the frond is
lanceolate, tapering to a point, broad in the centre and narrowing
slightly at the base. The frond of the Common Polypody is cut in a
pinnatifid manner. The lobes, which are more or less rounded at the tip,
are separated by openings in which the leafy portion is cut almost down
to the rachis. Now and again the margin of the lobes is somewhat toothed.
[Illustration: Polypodium vulgare. The Common Polypody.]
On the back of the frond are to be found the sori. These are disposed on
both sides of the mid-ribs of the lobes; they are circular in shape and
have no indusia or covering of any kind. When the sporangia are young the
sori are of a very pale yellow colour; this changes to a rich
golden-brown as the capsules mature. The sori are mostly confined to the
upper portion of the frond, and on account of their bright colouring add
very much to the appearance of the leaf. There are a large number of
varieties of the Common Polypody.
[Illustration: Enlargement of the sori on the frond of Common Polypody.]
The Common Polypody will, of course, grow in almost any position. It
often finds a home amongst the branches of old oak trees, whilst it seems
to be equally happy on the wall or the hedge-bank. It is of fairly easy
culture in the garden, though the plant likes a well-drained situation.
The Common Polypody is an evergreen species.
[Illustration: Polypodium phegopteris. The Beech Fern.]
_Polypodium phegopteris._ Here the specific name is formed of two Greek
words—_phegos_, “a beech,” and _pteris_, “a fern.” This is, of course, a
rendering of the popular name, though why the species has been called the
Beech Fern nobody seems to know. Certainly the species is not like a
Beech, neither can it be said to grow in association with this tree. The
Beech Fern or Mountain Polypody.
This species has a slender creeping rhizome from which arise the dainty
light green fronds. The fronds vary from about six inches to a foot in
length; the stipes is longer than the leafy portion, and is of a light
green colour. The outline of the leafy part is triangular in form, and on
either side of the rachis are the tapering pinnæ. At the top the frond is
pinnatifid, whilst the lower pinnæ are deeply cut. A very distinctive
feature of the Beech Fern is the way in which the lower pair of pinnæ
point downwards away from the tip of the frond.
Nearly the whole of the underside of the frond bears the sori. These are
placed quite near to the margins of the lobes of the pinnæ. Like all the
Polypodies the clusters of sporangia have no indusia.
The Beech Fern cannot be called a common species, though it is often
abundant in certain localities. It is much more frequent in Scotland than
elsewhere, and may be looked for hopefully in almost any moist wood. It
also occurs abundantly in some parts of the North of England. Unless the
Beech Fern can be given a moist position it is not an easy plant to grow
in the open garden. It is, however, successfully cultivated in the
greenhouse. The plant dies down in the winter, and the new fronds do not
appear until somewhat late in the spring.
_Polypodium dryopteris._ Here the specific name is derived from two Greek
words—_drus_, “an oak,” and _pteris_, “a fern.” Here again it is not easy
to see a resemblance between this fern and an oak, unless it be that the
newly-developing fronds are in colour something like the delicate green
of the tree when it is decked in its new foliage. The Oak Fern or
Three-branched Polypody.
This plant has a thin creeping rhizome from which the fronds arise. The
stipes is of a pale green colour, and it is usually longer than the leafy
portion. Actually the frond is divided into three branches, each of which
is triangular in shape and pinnate towards the base, becoming pinnatifid
at the tip. The pinnæ are deeply segmented. The unrolling of the frond is
a very novel feature of this Fern, each branch at this time appearing to
be like a small coil of wire. In its early days the golden green colour
of the frond is very much pronounced, but as the leaf ages a deeper tone
is assumed.
The sori are disposed near to the margins of the lobes of the leaves, and
these are circular and without indusia. The lower pinnæ of the Oak Fern
do not point downwards, as is seen in the case of the Beech Fern.
The Oak Fern is common in many parts of Scotland, and is to be seen
carpeting the ground of many a moist wood. It also occurs in England
chiefly in the northern counties. In some parts of Wales it is to be
found in plenty, but the species is said to be rare in Ireland. The Oak
Fern grows in a damp and shady spot in the garden, though it is often
more happy in a pot. The fronds of the plant die down in winter, and the
fresh ones do not start until late in the spring.
In some books a species called _Polypodium calcareum_ (The Limestone
Polypody) is described. In some quarters this plant is regarded as a
variety of _P. dryopteris_, as it is similar in some respects. Mr. C. T.
Druery considers it to be a distinct species. The chief points of
difference are said to be the following. The whole plant is larger in
growth, whilst the green of the fronds is not such a golden colour, even
in the early days. Also the pinnæ are not arranged so definitely in the
form of three branches, as is to be observed in the case of the Oak Fern.
Finally, the unrolling of the frond does not present the appearance of
three little balls, seeing that each pinnæ unfolds separately. The
Limestone Polypody occurs chiefly in the North of England.
_Polypodium alpestre._ The Alpine Polypody. This is a most remarkable
species, in that it bears a singular resemblance to the Lady Fern. By
some authorities it is positively regarded as a Mountain form of the Lady
Fern. The reason for linking the species with the Polypodies is found in
the rounded sori, which have no indusia. The Alpine Polypody has a short
tufted root-stock, and from this arise the fronds, which may be a foot or
even more in height. The stipes is very short when compared with the
leafy portion, and it is covered with brown scales. The general outline
of the fronds is broadly lanceolate, and they are twice divided. The
pinnæ are arranged in alternation on either side of the rachis, and these
are divided into pinnules with blunt points. The pinnules have toothed
edges. The sori are chiefly situated near to the inside border of the
pinnules. Those who consider that the Alpine Polypody is a form of the
Lady Fern call the species _Pseudathyrium alpestre_.
The Alpine Polypody seems to be exclusively confined, as far as the
United Kingdom is concerned, to the highlands of Scotland. It is
sometimes to be found at an altitude of four thousand feet above
sea-level. In spite of its restricted locality the Alpine Polypody is an
easy subject for the garden, if it can be provided with a well-drained
situation.
CHAPTER IX
THE ROYAL FERN
Under the name of the Flowering Fern it is probable that most people are
familiar with the subject we are now about to consider. The title has
without a doubt arisen from the fact that the species bears its sori in
masses at the termination of the fronds, quite apart from the leafy
portion. The Royal Fern is the sole British representative of the family
Osmundaceæ.
_Osmunda regalis._ There is great diversity of opinion upon the
derivation of the name Osmunda. The name is thought to be of Saxon
origin, and possibly was given to the Fern in honour of a personage who
bore the name of Osmund. Osmunda was one of the titles of the great god
Thor. In other quarters the name is said to be compounded of the two
words os, “a house,” and _mund_, “peace.” Finally, a pretty story
associates the name Osmunda with a certain Osmund, a ferryman, who, to
hide his daughter from marauding Danes, placed her amongst the great
clumps of the Royal Fern which grew so plentifully by the riverside. The
specific name _regalis_ is simply Latin for “royal,” and is an apt
reference to the noble proportions of this Fern.
[Illustration: Osmunda regalis. The Royal Fern.]
The Royal Fern has a sturdy tufted root-stock which in an old example may
well be one or two feet in height. From the crown of the root-stock arise
the fronds, which are of a yellow-green colour when they are young. The
stipes is about the same length as the leafy portion, and the fronds
themselves often rise to a great height. Cases are on record where, the
plant being in a very damp situation, the fronds have been as much as
twelve feet in height. Average specimens would range from three to six
feet. The fronds are twice pinnate, the pinnules being oblong with uncut
edges. Some of the fronds are barren and never bear any sori.
In the case of the fertile fronds only the upper portion produces the
clusters of spore cases. Here the leafy portion of the pinnules is very
much contracted, so that little or no green is visible. The sori are
quite naked, no indusia being present at any time. A notable feature of
the sporangia is that they split up into two valves when about to burst,
and are not provided with the elastic ring (_annulus_) which assists in
the rupture of the capsules in the case of most ferns. That the pinnules
which bear the sori are exactly comparable to the leafy portion is often
very plain. Here and there on a plant it is possible to find fertile
examples which have developed partly in a barren, and partly in a fertile
manner.
The Royal Fern is essentially a plant of the marshland. It never grows
happily in dry or elevated situations. It is perhaps to be found at its
best growing by the side of some river or stream. The Royal Fern has been
found in many parts of the United Kingdom, though the plant suffers much
from the depredations of trippers. Most fern-lovers know of places where
this handsome species grows in abundance, but they wisely keep such
knowledge to themselves. In the garden the Royal Fern grows well, but it
must not suffer from lack of water, or it will prove but a poor subject.
The fronds of the Royal Fern die down at the coming of the frost, and the
young growth does not put in an appearance until the late spring.
CHAPTER X
FOUR CURIOUS FERNS
The three species which must now be described would hardly be recognized
as Ferns at all by most people. It has been indicated in an earlier
chapter that there is really some doubt as to their true position, but
for the sake of convenience they are here included amongst the Ferns. All
the British species of the family Ophioglosseæ are somewhat inconspicuous
plants, owing to their habit of growing mixed up with a lot of herbage.
_Ophioglossum vulgatum._ The generic name is formed of two Greek
words—_ophios_, “a snake,” and _glossa_, “a tongue”; a reference to the
fact that the barren leaf was thought to bear a resemblance to a snake’s
tongue, though it must be confessed that the likeness is not very
apparent. The word “vulgatum” is, of course, Latin for “Common.” The
Common Adder’s Tongue.
In this species the frond is very definitely divided into two parts, a
leafy portion and a spike. These are borne on a stalk about six inches in
length which arises from a fleshy root-stock. The roots of the Common
Adder’s Tongue are quite coarse and entirely unlike the wiry roots of the
majority of ferns. The leafy or barren portion of this curious frond is
not divided in any way and is roughly egg-shaped. The fertile portion is
in the form of a stalked spike, the spore cases being arranged on either
side in double rows. The capsules are rounded in form and have no elastic
ring, but open transversely when the contents are ripe. Attention should
be called to the beautiful veining of the barren leaf of the Common
Adder’s Tongue, which forms a perfect network through the green tissue.
[Illustration: Ophioglossum vulgatum. The Adder’s Tongue.]
The Common Adder’s Tongue is really very abundant in many parts of
England. It should be looked for in damp meadows, and will probably be
difficult to find without a close search. It is not so abundant in
Scotland and Ireland. The only way to secure the plant safely for
cultivation is to cut up a piece of turf, and remove the whole thing into
a position where the soil is moist and rich. The Common Adder’s Tongue is
not very often cultivated, as from the gardener’s point of view its
decorative value is small. The new frond of the Common Adder’s Tongue is
fully developed by June, and it disappears early in the autumn.
_Ophioglossum lusitanicum._ Here the specific name is taken from
Lusitania, the old designation of Portugal—a reference to the fact that
the species is abundant in that country, as indeed it is in other parts
of Southern Europe. The Little Adder’s Tongue.
This plant is really a miniature addition of the former species. There is
no doubt, however, that it is to be regarded as a distinct type, although
at one time it was thought to be merely a variety of _O. vulgatum_.
As far as the United Kingdom is concerned the Little Adder’s Tongue has
only been discovered in one or two localities. Some years ago it was
stated to have been found in Cornwall, and it certainly used to occur in
Guernsey.
_Botrychium lunaria._ The generic name in this case comes from a Greek
word which means “a cluster,” this being a reference to the packed sori
of the fertile pinnæ. The specific name comes from the Latin _luna_, “the
moon,”—an allusion to the curiously-shaped pinnæ on the barren part of
the frond. The Moonwort.
[Illustration: Botrychium lunaria. The Moonwort.]
This is an interesting species which is easily distinguished from the
Adder’s Tongue. The plant has a fleshy root-stock from which arises a
frond divided into two parts, a leafy portion and a fertile branch. The
whole frond is about six or eight inches in height, and the stipes is
usually more than half the entire measurement. The leafy branch is
pinnate, and its divisions are curious crescent-shaped processes which
may be toothed round the edges. These are usually rather crowded together
on the stem. The fertile portion of the frond is very upright, and bears
about the same number of branches to be counted on the leafy portion.
These branches are again divided into sections which bear the clusters of
spore cases. These are of a reddish-brown colour and burst open when the
contents are mature, in the same manner as that to be seen in the Adder’s
Tongue. In the Moonwort, as in the previous species, it is possible to
find the next year’s frond concealed at the apex of the root-stock.
The Moonwort grows in drier situations than that which suits the Adder’s
Tongue. It is abundant in many parts of England, and is a very common
plant in localities in Yorkshire. The species also occurs in other parts
of the United Kingdom, though on account of its habit of growing mixed up
with grass, the Moonwort is often overlooked.
The following is the only indigenous species related to the Gold and
Silver Ferns of our greenhouses:—
_Gymnogramma leptophylla._ The generic name is derived from two Greek
words—_gymnos_, “naked,” and _gramme_, “a line”; an allusion to the
unprotected sporangia. The specific name means “slender leaf.” The Annual
Maidenhair.
This is a pretty little species with barren and fertile fronds of a
bright green colour. In some respects the fronds resemble those of the
true Maidenhair. The Annual Maidenhair only occurs in Jersey, as far as
the United Kingdom is concerned.
CHAPTER XI
THE CLUB MOSSES
As we have seen, the living species of the Club Mosses are comparatively
insignificant plants. None the less, most of them are attractive each in
its own way, and it is interesting to be able to identify the different
kinds. First of all we may consider the five species of Lycopodium.
_Lycopodium clavatum._ Here the generic name is derived from two Greek
words—_lukos_, “a wall,” and _pous_, “a foot.” One of the popular names
of the plant is Wolf’s Claw; possibly an allusion to the curious
branching-stem, although it must be confessed that the plant is not very
claw-like. The specific name is derived from the Latin _clava_, “a club”;
this having reference to the cones, or club, which bears the sporangia.
The Stag’s Horn Moss, or the Common Club Moss.
[Illustration: Lycopodium Clavatum. The Common Club Moss.]
This species has wiry stems of considerable length, sometimes measuring
as much as six or eight feet. These run along close to the soil, to which
they are attached at intervals by strong roots. The stems which branch in
all directions are covered with small narrow leaves, each of which ends
in a curious little bristle. This gives to the whole plant a singular
grey appearance. These hair-like points to the leaves may be regarded as
a distinct feature of the Common Club Moss. In the autumn the fruiting
spikes of the Common Club Moss are borne on the ends of erect stalks. The
cones are generally about an inch in length, and at times as many as two
or three of them may be allotted to each stalk. If closely examined it
will be found that the fruiting spikes are composed of a number of
leaf-like bracts, each one of which bears the case filled with spores.
After the dispersal of the spores the cones fall off, but the plant as a
whole remains green throughout the winter.
The Common Club Moss is often very abundant upon the moors of the North
of England, and also in Scotland and in Wales. On account of its creeping
habit of growth the plant is often overlooked, and few people realize
that this Club Moss is really very common. Sometimes single plants cover
huge areas of ground, and many of the trailing stems are several feet in
length. The spores of this, in common with those of other Lycopodiums,
are inflammable; and in the old days these were used in the manufacture
of fireworks.
_Lycopodium selago._ In this case the specific name of _selago_ was that
formerly given to all the Club Mosses. The Fir Club Moss.
This is a very pretty little plant, which, on account of its upright
habit of growth, attracts a good deal of attention. The stems vary from
about three to six inches in height, and these rise upwards from a main
stem which sometimes, but not always, trails along the ground for a short
distance. The branches are very thickly covered with leaves which overlap
one another, and are very stiff. Indeed, the whole plant is covered with
the foliage, which, being narrow and pointed, is almost bristle-like in
appearance. The colour of the foliage is bright green. The spore capsules
are present in the axils of the uppermost leaves of the branches, and
these are kidney-shaped. The Fir Club Moss is also very commonly
propagated by means of special little buds which appear at the tops of
the branches. When these are developed they fall to the ground, and give
rise to fresh plants.
The Fir Club Moss is probably almost as common as the Common Club Moss.
It should, however, be looked for on elevated moors and the slopes of
mountains.
[Illustration: Lycopodium selago. The Fir Club Moss.]
_Lycopodium inundatum._ Here the specific name has reference to the fact
that this Club Moss grows in situations which are often under water. The
Marsh Club Moss.
This is a peculiarly interesting species, in that it is the only British
Club Moss to be found in lowland districts. The stems of the plants are
prostrate, and these are so closely fixed to the soil with strong roots
that it is almost impossible to remove a specimen without taking away the
soil as well. The fertile branches rise in a very direct manner to the
height of two or three inches, and these, like the main stems, are
thickly covered with narrow leaves, which have sharp points. The
fructification is produced in the autumn, the capsules being borne
between leaf-like scales at the upper part of the shoot. A singular thing
about the Marsh Club Moss is that one end of the creeping stem is always
decaying, and an individual plant is rarely more than a few inches in
length. In the winter only the growing tip of the plant remains, and from
this the whole of the new development arises.
The Marsh Club Moss is comparatively rare in the North of England, though
in the South and West it is often to be found. As a rule it occurs in
large isolated patches, and one may hunt for some distance around before
finding any more specimens. It likes a thoroughly wet situation, and on
this account is soon stamped out when any schemes of land drainage are
undertaken.
_Lycopodium alpinum._ In this case the specific name is simply a
reference to the fact that this Club Moss grows in mountainous districts.
The Alpine Club Moss.
This species has long creeping stems which are rather bare of leaves.
From these, however, spring the upright branches which are thickly
covered with foliage; every one of the leaves terminates in a point. The
Alpine Club Moss is an evergreen plant, and it is of a very bright green
colour. The branches which bear the fertile spikes are somewhat taller
than the barren ones, and these are often twice forked. The cone bears a
number of thin scales, and between each of these and the stem is to be
found the kidney-shaped capsules.
The Alpine Club Moss is often to be found in great abundance in elevated
districts in Scotland and Ireland. It seems to be most happy in elevated
situations.
_Lycopodium annotinum._ In this case the specific name is from the Latin
term signifying “a year old.” This is an allusion to the fact that the
yearly additions to the plant are very evident. The Interrupted Club
Moss.
This species at first sight is sometimes taken for the Common Club Moss.
It is, however, readily distinguished when its branches are examined;
these are increased annually by an addition which is very plainly to be
observed. It is seen that at these periods the leaves are smaller and
much less inclined to spread than in the normal forms. At times the
branches divide, and at the tip of some of the upright shoots occur the
fertile cones. Each one of these is about an inch long, and it is covered
with bracts upon which the spore capsules are borne. The Interrupted Club
Moss is a fine species, and is of a pale green colour.
This is probably the rarest of our native Club Mosses. In some parts of
Scotland it is said to be abundant, but the plant is always a local one.
It has been found in the North of England, though it is decidedly
uncommon.
In the United Kingdom there is only one native species of Selaginella.
_Selaginella spinosa._ In this case the generic name is derived from the
name Selago; actually the name means “a little Club Moss.” The specific
name has reference to the tiny spines on the margins of the leaves. The
Lesser Alpine Club Moss.
This plant is, of course, very distinct from the Lycopodium, in that it
produces two kinds of spores. The Lesser Alpine Club Moss is a small
plant with both prostrate and upright stems. The leaves are very tiny,
and owing to their semi-transparent nature the whole plant is of a pale
green colour. Some of the upright stems are barren, but a certain
proportion bear the spore capsules in the axils of the small leaves. In
the upper part of the cone occur the capsules containing the microspores,
whilst in the lower portion are to be found the sporangia, each of which
produces three or four megaspores.
The Lesser Alpine Club Moss is probably more common than is generally
supposed, especially in the North of England. It grows in damp situations
and is often very much mixed up with other herbage, so that it is easily
overlooked. It is now necessary to describe the two or three curious
little plants which are closely related to the Ferns and Club Mosses.
_Isoëtes lacustris._ In this case the generic name originates in two
Greek words—_isos_, “equal,” and _etos_, “a year.” This has reference to
the fact that the plant keeps its leaves all through the year and does
not alter in appearance. The specific name _lacustris_ is derived from
the Latin word _lacus_, a lake, and is an allusion to the fact that the
plant grows in such a situation. The Quillwort.
This is an interesting little plant which is entirely aquatic in its
habits. The Quillwort has a tuberous root-stock, and from this arise a
large number of dark green leaves, somewhat resembling quills in shape.
These are about three or four inches in length, and when the plant is
growing in quantity in some pool, it is often taken for a kind of grass.
At the base of the leaves, partly protected by the sheathing, are to be
found the spore capsules. These cases are of two kinds, those on the
outermost rows of leaves containing the large spores, and those on the
inner leaves being responsible for the small spores.
[Illustration: Isoëtes lacustris. The Quillwort.]
The Quillwort is often abundant in mountain lakes in Scotland and the
North of England. Owing to its habit of growth, however, the plant is
usually unnoticed by the majority of people.
Another species of Quillwort—_Isoëtes Hystrix_—occurs in the Channel
Islands, but it has not been found elsewhere in the United Kingdom.
_Pilularia globulifera._ In this case the generic name is formed from the
Latin word _pilula_, “a little pill,” this being a reference to the
curious pill-like spore capsules which the plant produces. The specific
name of _globulifera_ is made up from two Latin words—_globus_, “a ball,”
and _fero_, “I carry.” This is another allusion to the rounded sporangia.
The Pillwort.
This is a curious little plant with a very slender creeping root-stock.
From this are sent down small tufts of roots into the damp soil in which
the plant grows. From the upper part of the stem arise the leaves, which
are bristle-shaped, two or three inches in length, and of an intensely
bright green colour. It is interesting to note that in their young state
these leaves uncoil very much in the same manner to be noticed in the
Ferns. The spore cases are situated at the point where the leaf arises
from the root-stock. Externally these are densely covered with brown
hairs, and they are just about the size of a small pea. The sporangia are
four-celled, and when the time for the dispersal of the spores arrive,
the cases split open. The spores are of two kinds, and both sorts are
present in the same sporangia. The large spores are confined to the lower
portion of the case, the small ones to the upper part.
The Pillwort is common in some parts of England, though less so in
Scotland and Ireland. It always grows in very damp situations, though it
is rarely found submerged, save when this happens as the result of
flooding. The Pillwort so often grows mixed up with grass, which in some
ways it resembles, that the plant is frequently overlooked.
[Illustration: Azolla caroliniana.]
_Azolla caroliniana._ Here the generic name is derived from two Greek
words—_azo_, “to dry,” and _ollo_, “to kill”—an allusion to the fact that
dryness is fatal to the well-being of the plant. The specific name has
reference to the fact that the plant is very abundant in Carolina, though
as a matter of fact it occurs in other parts of the world. It should be
pointed out that the Azolla is not a native of the United Kingdom, but it
has become well established in some parts of the South of England.
During the summer time the Azolla, which is a floating plant, increases
with great rapidity, sometimes completely covering the surface of a lake.
At first the fronds, which are exquisitely beautiful, are of a
silver-green colour; towards the autumn they assume a bright crimson
tint. Underneath the fronds are produced a large quantity of roots which
hang down into the water. Two kinds of spores are produced. The
microspores are packed away in cases which are provided with curious
barbed contrivances. The megaspores bear hooks, and in this way the two
processes become attached. The Azolla is a pretty plant to grow in an
aquarium, though where it has been able to make itself at home it will
sometimes increase so vigorously that all other vegetation is killed.
CHAPTER XII
THE HORSETAILS
It is now necessary to consider a very striking order of plants. Unlike
the Club Mosses, it is probable that most people are familiar with one or
more species of Horsetail; some of these plants are not only common, but
they are also very striking in appearance. In all there are eight species
of _Equisetum_ which are natives of the United Kingdom, and most of these
are fairly easy to identify if a few leading features are borne in mind.
_Equisetum arvense._ The generic name in this case is composed of two
Latin words—_equus_, “a horse,” and _seta_, “a bristle.” Thus we see that
the popular name of the plant is an almost exact translation of the
scientific one. The specific name is derived from the Latin adjective
_arvus_, “a field,” and has, of course, reference to the fact that the
plant grows in pastures. The Field Horsetail.
[Illustration: Barren stem of Equisetum arvense.]
This species is by far the commonest of all the Horsetails, and is very
frequently to be found on embankments in fields and by the sides of
roads. The plant, which dies down in the winter, starts its growth quite
early in the year with the development of the fertile stems. These rise
straight up from the branching root-stock, and are generally about five
or six inches in height. The stem, which is of a very pale colour, is of
rather a succulent nature; it is hollow in the centre and in a certain
way reminds one of bamboo. At intervals there are certain sheaths which
are divided into a number of teeth with very sharp points. The cone-like
fructification is about an inch in length and bears a number of peltate
scales to which the spore capsules are attached. The spores are ready for
dispersal in the month of May. Just about this time the barren stems put
in an appearance. These rise to the height of two feet, or even more, and
have many whorls of spreading branches which in their turn may again be
branched. It is these branches which carry on the real vegetative work of
the plant. For the real leaves we must examine the sheaths, which with
their wedge-shaped teeth are to be found at the stem joints. The teeth
are the only free portions of the leaves of the Horsetails. It is
interesting to note that in each whorl the branches are equal to the
number of leaves and are alternate to them. The stem of the barren
branches of the Field Horsetail is slightly marked with furrows, which
vary in number. The branches are usually only four-furrowed, and have
sheaths with the same number of teeth.
The whole of the barren portion of the Field Horsetail is very rough to
the touch. This is due to the fact that the plant is covered with tiny
flinty particles. That the measure has a protective value is very
evident, for cattle have hardly ever been known to eat the plant.
_Equisetum maximum._ In this case the specific name, of course, means
great, and has reference to the fact that the species is the largest of
all the kinds. In some old books this species is given as _E. Telmateia_
and _E. fluvialis_. The Great Horsetail.
[Illustration: Fertile cones of Equisetum maximum.]
This is by far the most striking of all our native Horsetails. As a rule
the plant grows in a damp situation, and it then assumes handsome
proportions. The fertile stems appear on the scene about April, and these
do not as a rule exceed a foot in height. They are very succulent, and
have loose sheaths which have about thirty or forty teeth. The sheaths
are green at the lower, and brown at the upper part, being distinctly
marked with lines. The fertile cones are three or four inches long and
possess a very large number of scales. The barren stems are remarkable
for their erect growth, and in a fine specimen these may be four or five
feet in height. The stem bears numerous whorls of branches, and these
branches may show yet further divisions. As a rule each whorl has thirty
or forty branches apiece. On the upper part of the stem the whorls are
very close together, but they are more widely separated at the lower
portion. The main stems, which taper towards the apex, are marked with
lines, and at intervals are enclosed in sheaths; these have long teeth
and fit the stem very closely. The branches are rough to the touch, and
have sheaths which end in four or five teeth; each tooth in this case is
prolonged into a bristle which has two toothed ribs. This is a feature by
means of which it is always possible to distinguish the Great Horsetail
from any other species. Now and again stems have been found which, whilst
bearing fertile cones, at the same time branch in the manner to be
observed in the case of the barren stems.
The Great Horsetail is widely distributed and is sometimes very abundant,
though it is not so common as some of the other species of _Equisetum_.
_Equisetum pratense._ In this case the specific name is a Latin word
which means “growing in a meadow.” In some books this plant is known as
_E. umbrosum_. The Shade or Blunt-topped Horsetail.
This species has three kinds of stems. The first of these is about six
inches in height, and is provided with large loose sheaths. This bears
the cone of fructification, which is ripened about the month of April.
The second type of stem produces both branches and a fertile cone, though
this latter is very much smaller than in the case of the first type of
stem. Finally, there is the barren stem, which may be about eighteen
inches in height; this is very rough, and has about twenty
strongly-marked ridges. The sheaths, which are not so large as those of
the fertile stem, fit somewhat closely. The stem branches freely, and it
is to be noted that these branches have three or four ridges; as well,
they bear sheaths which end in the same number of teeth. A distinctive
feature of the Shade Horsetail is that the topmost whorls of branches
spread upwards in such a way that they reach the summit of the stem;
there is no long tapering point such as is to be seen in the case of the
Field Horsetail, for instance. The result of this habit of growth is that
the plant has a curious flat-topped appearance; it is on this account
that the species has received one of its popular names.
The Shade Horsetail grows in damp meadows and very shady woods, though it
is not common in all districts.
_Equisetum sylvaticum._ In this case the specific name is taken from the
Latin _silva_, “a wood,” and is a reference to the habitat of the plant.
The Wood Horsetail.
This is one of the most beautiful of our Horsetails. The plant has two
kinds of stems, both of which are ultimately branched. The fertile stems
put in an appearance first of all in the early spring; at this time these
bear only a cone and are without branches. With the dispersal of the
spores the cone shrivels up, and then the stems starts to send out green
branches. These branches give off whorls of smaller branches from their
joints. In a general way the stems of the barren shoots are not so
succulent as those which bear the cone; the barren stems, too, are
somewhat taller and branch more freely than the fertile ones. In both
barren and fertile stems are to be noticed the whorls of small drooping
branches which give a characteristic appearance to the Wood Horsetail,
and by means of which it may always be identified. The sheaths which
enclose the stem evidence three or four teeth, whilst the terminal
branches (which are three-ribbed) bear at each joint a sheath ending in
three long pointed teeth. The stems of the Wood Horsetail are marked by
about a dozen ridges.
The Wood Horsetail is often abundant in damp shady woods.
_Equisetum palustre._ The specific name _palustre_ means “belonging to
the marshes.” The Marsh Horsetail.
This plant has a very thick rhizome from which arise the erect stems. The
barren and the fertile stems closely resemble each other, being about a
foot or more in height, with very rough surfaces on which it is possible
to count from six to twelve very prominent ridges. The stems are enclosed
at intervals in loose sheaths, which have the same number of teeth as the
ridges on the stem. It should be noted that the branches from the various
whorls show a marked tendency to turn upwards. On certain of the stems
the fertile cone appears and the spores are ripened about June, after
which the process withers. The plant as a whole remains green until late
in the autumn. Sometimes in the case of large plants, cones have been
known to occur on the tips of the branches of the Marsh Horsetail.
The Marsh Horsetail is a very common species, often growing in the
greatest profusion by the sides of pools.
_Equisetum limosum._ In this case the specific name is a Latin word which
means “full of mud”; this being an allusion to the fact that the plant
favours swampy situations. The Smooth Naked Horsetail. The plant is also
called the Water Horsetail.
A distinctive feature of this plant is that it has almost completely
smooth stems, though a close examination will indicate the presence of a
number of slight ridges. The barren and the fertile stems are very
similar, and in a favourable situation they will grow to the height of
two or three feet. A curious feature of this plant is the irregular way
in which the branches appear. Sometimes the stems are quite bare; on
other occasions they are partly branched; in any case the branches are
short. The sheaths with many teeth are closely pressed to the stem. The
fertile stem is, of course, distinguished by the cone which it bears at
the summit. It is said that cattle are not averse to eating the Smooth
Naked Horsetail, and certainly the stems are not unpleasant to the touch.
The Smooth Naked Horsetail is a common plant, specially by the sides of
streams and pools. It sometimes grows right in the water.
_Equisetum variegatum._ Here the specific name means variegated, and has
reference to the fact that the sheaths enclosing the stem are pale green
below and blackish in colour above. The Variegated Rough Horsetail.
As a rule this plant grows by the seashore, where, by means of its
fibrous roots, it may play a useful part in helping to bind the shifting
sand. The Variegated Horsetail is not exclusively maritime, however, for
it sometimes grows by the sides of rivers and ponds. The barren and
fertile stems closely resemble one another, and they are very nearly
prostrate in habit. As a rule they are about a foot in height, and the
stems have from four to ten ridges. The upper part of the stem is usually
unbranched, but whorls of branches occur towards the base. The sheaths,
which, as already stated, are green below and black above, fit very
closely to the stem. The black teeth have white margins, and terminate in
bristle-like points. The cones are borne at the summit of the fertile
stems, and are comparatively small.
The Variegated Rough Horsetail occurs chiefly, though not exclusively, in
the North of England.
[Illustration: Equisetum hyemale. The Dutch Rush.]
_Equisetum hyemale._—In this case the specific name is a Latin adjective
which means “pertaining to winter,” an allusion to the fact that the
plant is to be found all through this season. The Rough Horsetail or
Dutch Rush.
This is quite the most distinct of all the Horsetails. There are none of
the whorled branches which are so familiar in the other species, and it
is only now and again that even a single branch is produced from the base
of one of the sheaths. There is a strong resemblance between the barren
and the fertile stems. These are both tall and very erect, usually
running up to the height of two or three feet. The stem is very rough to
the touch, and is marked with from fourteen to twenty ridges. The edges
of these ridges are thickly covered with flinty particles. The sheaths of
the Dutch Rush clasp the stem of the plant very closely. The fertile cone
is small, and is placed at the top of the stem.
The Rough Horsetail is not a very common species, but is abundant on the
Continent, especially in Holland and Germany, where it is largely
employed for the fixing of the soil of embankments. The Rough Horsetail
is very useful for polishing wood.
CHAPTER XIII
FERN COLLECTING AND PRESERVING
Perhaps none of our native plants have suffered more from those vandals
who root up every pretty thing they see than the Ferns. To the average
tripper there seems to be something irresistible in the green fronds, and
up comes the root, or enough of it to destroy the plant, and the prize is
carried home. Even if the fern is so fortunate as to be planted at all,
it is probably dealt with in such a way that its chances of living are
very remote. County Councils may pass by-laws, but one is afraid that
these will have little effect until there is amongst the people as a
whole a more wide-spread regard for natural beauty. It is to be feared
that one cannot entirely acquit the scientific student of helping in the
destruction of Ferns. A rare find is a terrible temptation to the
enthusiast, but if the plant is a solitary one it is a golden rule to
leave it alone. Often enough a single frond will give us any quantity of
ripe spores from which fresh plants may be raised. In any case the
gathering of the leaf is a certain proof that one has found the
particular species. If it is possible to re-visit the spot at a later
date it is not unlikely that the specimen may have propagated itself in
some way. Of course, where there are a number of specimens there can be
no harm in taking one for cultivation. The same applies to common Ferns,
or varieties of these; and if by propagation the stock is increased the
number of beautiful plants in the country is made the larger. So that
there is a form of collecting which is perfectly legitimate, and, indeed,
to be commended.
For those who start out on a Fern collecting expedition, one of the long
narrow trowels will be found to be extremely useful. A proper vasculum
is, of course, of service, but this is sometimes apt to get in the way,
and it will not accommodate very large Ferns. Mr. C. T. Druery, who has
done an enormous amount of Fern collecting at home and abroad, declares
that he contents himself with some old newspapers and a ball of string.
In this way bundles of the plants are easily made, and in most cases
these can be readily carried about. Great care is necessary when removing
the Ferns to do as little damage as possible to the roots. If it is
desired that the plant should settle into its new home as quickly as
possible, it is an excellent plan to take away with it a certain amount
of soil. Of course, considerations of weight have to be taken into
account, but the more mould round the roots the better. Never grasp a
Fern plant from above and try to pull it away, as this will be almost
sure to result in damage. Rock Ferns are often exceedingly difficult to
remove, owing to the manner in which the roots of these plants spread to
great distances in the crevices. Yet without a large amount of their
roots these Ferns can never be satisfactorily established. In such cases
a chisel and a mallet will often come in highly useful, as in many
instances if the rock is chipped away the Fern can be readily taken from
its position. As the specimens are secured it is most important to take
steps to protect them from withering. First of all, wrap a portion of
damp newspaper round the roots, and then tie up with dry paper. When on a
holiday the Ferns may be kept alive and in good condition for a week or
so, if they are placed in some shady corner with their roots protected in
the manner described. An occasional sprinkling of water will help to
prevent any withering. Of course, for packing it is often necessary to
cut off some of the largest fronds; and there is not much lost by so
doing, for these often become very much damaged, and will probably die
when the plant is established in its new quarters. The question is often
asked at what time of the year may Ferns be removed. Nearly all our
native species will suffer transplanting at almost any season if the
business is carried out on the lines indicated. Of course, most specimens
are probably taken up in the summer when the handsome foliage attracts
the eye. In some ways this is the least satisfactory time on account of
the hot dry weather, but by protecting the roots there is no reason why
the specimens should flag to a harmful extent. Of course, newly acquired
Ferns will pay for extra attention in the way of watering until they have
secured a proper roothold.
A very interesting way of studying Ferns is that of collecting the fronds
of the species which the hunter may come across. This is a pursuit to
which no sort of objection can be taken, for, of course, the plant itself
is not in any way disturbed, and is not in the least likely to suffer
from having one or two of its fronds removed. In a general way the fronds
are best collected during the summer and autumn, when they will, of
course, be well developed. It is much more difficult to secure perfect
fronds than may be generally supposed, and even with the common species a
number of plants may have to be examined ere specimens without blemish of
some kind or another can be obtained. Seeing that the position and shape
of the sori play such an important part in classification, the fronds
should be secured when the patches of spore cases are developed. On the
other hand, these should not be quite ripe, or they will be likely to
burst in the process of drying, and the real character of the sori will
not be very apparent. When they are gathered the fronds should be placed
at once in a vasculum, or a long tin box, and must be kept there until
the time for pressing arrives. Naturally it is a good plan to treat the
fronds as soon as possible, though in a closed tin box they will keep for
some days without withering.
If properly dried and pressed, it is possible to preserve the Fern fronds
with a great deal of their natural colour. Botanical drying paper should
be employed, and, of course, if desired an orthodox press may be used;
but this is not really necessary. The cheapest plan is to secure two
boards of wood of a size to cover the sheets of drying paper, which are
placed between the boards. If the paper is about twelve by eighteen
inches this will accommodate moderate examples of most of the fronds. Of
course, special arrangements will have to be made for extremely large
leaves. It is not a bad plan to have two straps with buckles so as to
keep the boards together, and prevent them from moving when the Fern
fronds are in position. In the first place, two or three thicknesses of
the paper should be spread on one of the boards. Now take the same number
of sheets, and start to place these over the frond. Starting at the tip
of the leaf the divisions should be carefully spread out in such a way
that the frond as a whole is well displayed. To keep the frond in
position it may be useful to put a book on the paper as it is spread out.
A number of fronds may be accommodated between the two boards in this
way, but it is important to have two or three pieces of the drying paper
between each specimen. When all the fronds have been spread out in the
manner indicated the uppermost board is put on the top of the layers of
paper, and by means of the straps the pieces of wood are drawn together.
A very small amount of pressure should be employed in the first instance,
and a few light books on the topmost board will be all-sufficient.
After about twenty-four hours the fronds may be examined. They are still
comparatively supple, and any misplaced pinnæ may be re-arranged without
any difficulty. In any case, fresh pieces of drying paper must now be
used, and on to these the fronds are placed. It will be found that as a
whole they assume a flat position, and are very easily handled. A little
stiff brush, or the end of a hairpin, will be found very useful at this
stage to help in the working out of any refractory pinnæ. The pressing is
carried out in the same manner as before, only if it is decided to make
this the final stage of the process, the weights should be heavier. In
the case of very complicated fronds the process of examining may be
repeated three, or even more times, with intervals of twenty-four hours.
After two or three days it will be found that the fronds are quite dry,
and they should have retained almost all of their natural colour.
The fronds may be moved into a portfolio formed of sheets of stoutish
paper. They may be held in place by fastening a few strips of gummed
paper over the stipes and rachis. The name, locality, and date of
gathering should be added to each specimen. Of course, in all cases it is
a good plan to have two fronds, one showing the upper and the other the
under side. Where there are both barren and fertile fronds, an example of
each should naturally be included. Thus, a highly interesting collection
of fern fronds may be gathered together with a small amount of trouble.
One is often asked by those who wish to study British Ferns, where the
most interesting specimens are to be found. The answer to the question is
that it is always a wise plan to keep your eyes open wherever you go.
Many of our smaller ferns are readily overlooked even by the keenest
observers. The writer can call to mind an occasion when he sent away to a
London nursery to buy an example of the Wall Rue Spleenwort. At the time
he was living in a town, and without a long tramp into the country there
seemed to be no hope of securing a specimen. A few days after the arrival
of the purchased plant any quantity of the little Fern, in rather a
dwarfed form, it is true, was found growing in the crevices of a wall
adjoining a public road. The upper part of the wall being covered with
ivy, the Spleenwort found a position beneath the protecting shade, where
it attracted no attention from the passers-by. Of course, certain species
of Fern are extremely local, largely owing to the fact that they require
special conditions of soil, etc. It is therefore quite useless to look
for such in an average district. Many species flourish only in rock
crevices or on old walls. Others are to be found, as a rule, in rather
elevated positions, and we cannot hope to find them save in a mountainous
country. Finally, there are a great many Ferns which can adapt themselves
to a variety of conditions. The actual circumstances of their
surroundings will make them vary more or less from the type, and this
must always be borne in mind when specimens are being examined. In
another way identification is sometimes rather difficult, owing to the
fact that immature Ferns are often very misleading in their appearance.
Quite likely they may resemble another species altogether. It is
therefore only when a mature frond bearing sporangia is discovered that
it is possible in some cases to speak with certainty. Many British Ferns
evidence a marked tendency to “sport,” and this is a fact which the
beginner should always bear in mind. As a rule, however, even in the case
of extreme varieties, a careful examination of the specimen will enable
it to be identified.
CHAPTER XIV
THE CULTURE OF FERNS
It goes without saying that Ferns of all kinds are interesting plants to
grow in the garden and house. A few suggestions as to the culture of the
various species described has been appended in each case, but one or two
general remarks may not be out of place. First of all, it is desired to
correct the popular impression that Ferns are happiest in very wet
situations; true, these plants like plenty of moisture, but only one or
two of the British species are ever found actually growing with their
roots in water. On this account, great care should be taken to provide
well-drained positions. The best kind of rockery should not be solid
earth all through, and the plants will grow much better if there is a
core of heaped stones covered with a deep layer of soil. Of course, shade
is very desirable, and hardly any Ferns, even those kinds which grow on
walls, are seen at their best in very sunny positions. Happily in most
gardens it is possible to find a border with a northern aspect on which
it is not easy to grow flowering plants with much success; in such a
position Ferns will find a home that will suit them admirably.
Of course it is only the hardiest Ferns which can be expected to grow
well in the town garden. Many of the common, and strong-growing species,
however, do very well anywhere, the only attention which they require
being an occasional watering in dry summers. This will often save the
foliage from drying up, a happening which makes the plants rather
unsightly. Where the outside conditions are not very favourable,
practically all the British species may be grown with ease under glass.
In such conditions many kinds which do not flourish very freely in the
open garden, grow into handsome specimens. A case in point is the Sea
Spleenwort, which is an exceedingly difficult subject to establish out of
doors, yet it grows well as a pot plant. Whatever the species, it is well
to imitate the natural conditions as much as possible in the way of soil.
For instance, the Limestone Polypody is not happy unless there is a
certain amount of lime present in the soil. Ferns with upright
root-stocks do well in ordinary pots, but those which produce creeping
rhizomes are best accommodated in pans or baskets. One wonders why even
some of the common British Ferns are not more generally cultivated in
rooms. Small plants of the Lady Fern, for instance, make charming
specimens, and in the comparatively dense shade of the apartment the
fronds are unusually delicate in their form and colouring. In all forms
of room culture the great enemy is the dust which settles so freely on
the fronds, and the only way in which to combat this is through the
agency of frequent syringings.
Fern cases were very much in vogue some years ago, and this is really a
very delightful way of cultivating the plants. Of course, the old Wardian
cases can often be picked up at second-hand shops, but one of the
simplest devices is formed with the aid of a cloche similar to those
commonly used in French gardening. It is only necessary to have a zinc,
or a galvanized tray on which to stand the glass in an inverted position.
Some means or other should be devised for the drawing off of the
superfluous water from the tray, and the simplest of all is to arrange a
hole which can be stopped with a cork. Broken crocks should be strewn
upon the tray, and on to this is heaped peaty soil mixed with sand. A few
small rocks of some soft stone may be added, and in between these the
Ferns are planted. Of course, the Filmy Ferns (_Hymenophyllum_) and the
Bristle Ferns are good subjects, but many other species may be grown with
great success in this way. The two chief dangers are a very rank growth,
by means of which the stronger subjects overwhelm the less vigorous
plants, and too much moisture. Where the dampness is excessive the fronds
take on an unhealthy appearance, and mould may appear. The case should at
such times be opened for a few hours each day to admit the drying air.
The case may be kept in a light position, and when once under way it will
rarely need any additional water.
A very interesting practice is the raising of young Ferns from spores.
This is really a very simple undertaking, and almost always meets with
success if the precaution is taken to sterilize the soil used by baking
it in an oven. Afterwards it is, of course, necessary to moisten the
mould, and the spores are then scattered on the surface. Keep closely
covered with a bell glass and, in a few weeks, more or less, the baby
Ferns will start to put in an appearance.
Those who take up the cultivation of British Ferns will certainly become
interested in the immense range of varieties which some species have
produced. Not a few of these are extremely beautiful, and are well worth
growing on this account, quite apart from their peculiarity.
INDEX
A
_Acrosticheæ_, 10
Adder’s Tongue, 11
_Adiantum capillus-veneris_, 9, 41
Algae, 1
Alpine Club Moss, 105
Alpine Polypody, 92
Alpine Woodsia, 61
Alternate-leaved Spleenwort, 69
Alternation of generation, 2
Annual Maidenhair, 10, 100
Annulus, 8, 14
Antheridia, 17
Archegonia, 17
_Aspidieæ_, 10, 46
_Aspidium aculeatum_, 59
_angulare_, 60
_filix-mas_, 46
_lonchitis_, 57
_Asplenieæ_, 10, 66
_Asplenium adiantum-nigrum_, 10, 73
_bulbiferum_, 3
_ceterach_, 77
_filix-fæmina_, 66
_germanicum_, 69
_lanceolatum_, 74
_marinum_, 75
_ruta-muraria_, 10, 70
_septentrionale_, 68
_trichomanes_, 78
_viride_, 80
_Athyrium filix-fæmina_, 10, 66
_Azolla_, 7, 12, 110
B
Beech Fern, 10, 89
_Bennittiteæ_, 25
Black Maidenhair Spleenwort, 10, 73
Bladder Ferns, 10
_Blechnum boreale_, 84
_spicant_, 84
Blunt-topped Horsetail, 116
_Botrychium lunaria_, 11, 98
Bracken Fern, 3, 9, 29, 38
Bristle Fern, 8, 33, 131
Brittle Bladder Fern, 63
Buck’s Horn Plantain, 69
C
_Calamites_, 28
_Calamus_, 28
Caudex, 4
_Ceterach officinarum_, 77
Classification of Ferns, 7 _et seq._
Club Mosses, 6, 12, 26, 101
Classification of, 32
Economic importance of, 32
Life histories of, 30 _et seq._
Number of species of, 30
Coal deposits, 25, 31
Common Adder’s Tongue, 96
Common Club Moss, 12, 19, 101
Common Polypody, 26
Common Rue, 71
Conifers, 27
Crested Buckler Fern, 53
_Cryptogamme crispus_, 9, 44
Cryptogams, 2
_Cyatheaceæ_, 11
Cycads, 25
_Cystopteris_, 10
_alpina_, 65
_fragilis_, 63
_montana_, 64
_regia_, 65
D
_Davallia bullata_, 9
_Davalliaceæ_, 9
Druery, Mr. C. T., 91, 123
Dutch Rush, 32, 120
E
Elaters, 21
Elba, 62
Embryo, 18
Endosperm, 27
English Maidenhair (_see_ Maidenhair Spleenwort)
Equisetites, 28
_Equisetum_, 112 _et seq._
_arvense_, 114
_fluvialis_, 116
_hyemale_, 32, 120
_limosum_, 118
_maximum_, 114
_palustre_, 118
_pratense_, 116
_sylvaticum_, 117
_telmateia_, 114
_umbrosum_, 116
_variegatum_, 119
F
Female organs (_see_ Archegonia)
Fern cases, 130
Ferns, classification of, 7 _et seq._
Collecting and preserving, 122 _et seq._
Comparative sizes of, 29
Cultivation of, 129 _et seq._
Economic importance of, 31
General characteristics of, 4 _et seq._
Grown from spores, 131
Habitats of, 29, 128
In greenhouses, 130
Life histories of, 13 _et seq._
Ferns, number of genera and species, 28
Reproduction of, 13 _et seq._
Sometimes difficult to identify, 128
Where to find, 127
Fertilization of Ferns, 17 _et seq._
Field Horsetail, 112
_Filices_, 8
Filmy Ferns, 2, 8, 33, 131
Fir Club Moss, 19, 103
Flowering Fern (_see_ Royal Fern)
Flowering Plants, probable origin of, 26
Forked Spleenwort, 68
Fossil botany, 23 _et seq._
Fronds, 4 _et seq._
G
_Gleicheniaceæ_, 11
Gold and Silver Ferns, 10
_Grammitideæ_, 10
Great Horsetail, 114
Green Spleenwort, 80
_Gymmogramma leptophylla_, 10, 100
Gymnosperm, 27
_Gymnospermæ_, 27
H
Hard Fern, 84
Hard Prickly Shield Fern, 59
Hartstongue, 82
Hay-scented Buckler Fern, 55
Holly Fern, 57
Horsetails, 6, 27, 31, 112
Life histories of, 21
_Hymenophyllaceæ_, 8, 33
_Hymenophyllum_, 131
_tunbridgensis_, 8, 35
_unilaterale_, 36
_Wilsoni_, 8, 37
I
Indusium, 8, 14
Interrupted Club Moss, 106
_Isoëtaceæ_, 12
_Isoëtes_, 7
_hystrix_, 108
_Isoëtes lacustris_, 12, 107
L
Lady Fern, 10, 66, 130
Lanceolate Spleenwort, 74
_Lastria æmula_, 55
_cristatum_, 53
_fæniscii_, 55
_filix-mas_, 46
_montana_, 50
_recurva_, 55
_rigidum_, 56
_Lepidodendraceæ_, 12
Lesser Alpine Club Moss, 106
Life histories of Club Mosses, 18 _et seq._
of Ferns, 3, 13 _et seq._
of Horsetails, 21
Little Adder’s Tongue, 98
Limestone Polypody, 130
_Lomaria spicant_, 84
_Lycopodiceæ_, 12
_Lycopodium_, 12, 19
_alpinum_, 105
_annotinum_, 106
_clavatum_, 12, 19, 101
_inundatum_, 19, 30, 104
_selago_, 19, 103
Lycopodium Powder, 32
M
Maiden Hair, 9, 38, 41
Maidenhair Spleenwort, 78
Male Fern, 2, 10, 13, 46
Male organs (_see_ Antheridia)
Malic acid, 18
_Marattiaceæ_, 11
Marsh Buckler Fern, 49
Marsh Club Moss, 104
Marsh Horsetail, 118
_Marsiliaceæ_, 12
Megasporangium, 20
Megaspores, 20
Microsporangium, 20
Microspores, 20
Moonwort, 11, 98
Mosses, 1
Mother cells, 15
Mountain Bladder Fern, 64
Mountain Buckler Fern, 50
Mountain Polypody (_see_ Beech Fern)
N
_Nephrodium æmulum_, 55
_cristatum_, 52
_dilatatum_, 54
_filix-mas_, 10, 13, 46
_montana_, 50
_oreopteris_, 50
_propinqua_, 49
_pseudo-mas_, 49
_rigidum_, 56
_spinulosum_, 53
_thelypteris_, 49
_uliginosa_, 54
O
Oak Fern, 10, 90
Oblong Woodsia, 62
One-sided Filmy Fern, 37
_Ophioglosseæ_, 11, 96
_Ophioglossum lusitanicum_, 98
_vulgatum_, 11, 96
_Osmunda regalis_, 11, 93
_Osmundaceæ_, 11, 93,
Ovum, 18
P
Parsley Fern, 9, 44
Pepperworts, 12
Phanerogams, 22
_Philotaceæ_, 12
Pillwort, 2, 7, 12, 109
_Pilularia globulifera_, 12, 109
Pinnæ, 5
Pinnules, 5
Placenta, 14
_Plantago coronopus_, 69
Pollen grains, 27
_Polypodiaceæ_, 9, 10, 86
Polypodies, 86
_Polypodium alpestre_, 92
_calcareum_, 91
_dryopteris_, 10, 90
_phegopteris_, 10, 89
_vulgare_, 10, 86
_Polystichum aculeatum_, 59
_angulare_, 60
_lonchitis_, 57
Prickly Buckler Fern, 54
Prothallus, 17
_Pseudathryrium alpestre_, 92
_Pterideæ_, 38
Pteridosperms, 24
_Pteris aquilina_, 9, 38
Q
Quillwort, 7, 107
R
Rachis, 4
Reproduction, vegetative, 3
Reproduction of Ferns, 13 _et seq._
_Rhizocarpeæ_, 12
Rhizome, 4
Ribbon Ferns, 38
Rigid Buckler Fern, 56
Roots, 5
Rough Horsetail, 120
Royal Fern, 11, 93
Rue-leaved Spleen wort, 71
_Ruta graveolens_, 71
S
_Salvinia_, 12
_Salviniaceæ_, 12
Scaly Spleen wort, 29, 77
_Schizœaceæ_, 11
_Scolopendrium rhizophyllum_, 3
_vulgare_, 81
Sea Spleenwort, 130
Seed, 27
_Selaginella grandis_, 30
_spinosa_, 12, 30, 106
_Selaginellaceæ_, 12, 26
Selaginellas, 30
Life histories of, 29
Sex organs, 17
Shade Horsetail, 116
_Sigillariaceæ_, 12
Smooth Naked Horsetail, 118
Soft Prickly Shield Fern, 60
Sori, 7, 14
Spermatozoids, 17
Spleenworts, 10, 66 _et seq._
Sporangia, 6, 14
Spore cases (_see_ Sporangia)
Spores, 5, 15 _et seq._
Stag’s Horn Moss, 101
Stipes, 5
T
Three-branched Polypody (_see_ Oak Fern)
Tree Ferns, 4, 11
Triangular Buckler Fern, 55
_Trichomanes_, 30
_radicans_, 8, 33
Tunbridge Filmy Fern, 35
V
Variegated Rough Horsetail, 119
Vascular Cryptogams, 1 _et seq._
Economic importance of, 31
Vegetative reproduction, 3
W
Walking Fern, 3
Wall Rue, 10, 70
Wardian cases, 130
Water Club Mosses, 7
Water Fern, 7, 110
Water Horsetail, 118
Wolf’s Claw, 101
Wood Horsetail, 117
Woods, Mr. Joseph, 61
_Woodsia hyperborea_, 61
_ilvensis_, 62
_Woodsias_, 10
_Printed by_ Morrison & Gibb Limited, _Edinburgh_
Transcriber’s Notes
--Retained publisher information from the printed copy (the electronic
edition is in the public domain in the country of publication).
--Corrected some palpable typos, notably changing several misspellings of
‘filix-fæmina’.
--In the text versions only, text in italics is delimited by
_underscores_.
*** End of this LibraryBlog Digital Book "How to Know the Ferns" ***
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