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.