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Another distinct variety, called dentata, is generally
smaller, and almost always blunter in the form of its parts ;
this grows from six to eight inches high, and has ovate-lanceolate
pinnæ, with ovate, obtuse, pointless pinnules, which
are again divided on the margin into a series of short blunt
notches or teeth ; the venation is more simple, and the fructification
is more marginal, than in any of the preceding forms.
The most distinct of all the varieties, however, is one
which we have called Dickieana, after Dr. Dickie, its discoverer
; it has a more compact frond than any of the preceding,
grows from four to six inches in height, in outline
almost ovate, terminating in a point, the pinnæ ovate-lanceolate,
overlapping each other, the pinnules decurrent,' broad,
obtuse, with a few shallow, marginal notches ; the texture is
very delicate and herbaceous, and the fructification marginal.
It is of a deep green, and has often a degree of transi ucency
which makes it very interesting ; it is a constant variety
under cultivation.
The usual forms of this species occur abundantly in moist
mountainous districts, and also on walls, but generally in
moist rocky situations throughout the United Kingdom,
Ireland excepted, where it is comparatively rare. The same
species is very widely dispersed in various parts of the world.
The varieties are more rare, and we know of only one locality,
a sea-cave, near Aberdeen, in which Dickieana has been
found. Cystopteris fra g ilis may be said to have rather a
preference to limestone. Under cultivation it is one of the
most manageable of the smaller sorts, growing freely on
rock-work or in pots. Its fronds are produced very early in
spring, are often renewed during summer, and continue to
grow up in succession until the frost cuts them off. Being
so very delicate in texture, the ffrst frosts which have access
to them do this.
The names of Cyatliea fra g ilis, C. cynapifolia, C. anthris-
cifolia, C. dentata ; Cystea fragilis, C. angmtata, C. dentata ;
Polypodium fragile, P . cynapifolium, P . anthriscifolium, P.
dentaium, P . rlimticum ; Aspidium fragile , A. dentatum, and
A. rlmticum have been given by various authors to the different
forms of this variable species.
Cysto pt eris m o n ta n a , Link.—P\\& Mountain Bladder-
Pern. (Plate XIV. ffg. 2.)
This is the rarest of our native Perns, and hence is a
plant of great interest. I t is a small species, growing with
a slender creeping scaly stem, by the division of which it is
increased. The fronds, which grow up from this caudex, are
from four to six or eight inches high, triangular in outline.
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