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words—jnofy, and stichos, signifying many, and order ; and it
is applied to these plants in allusion to the numerous regular
lines of sori, which are seen distributed over the fronds.
P olystichum ac u le a t um , Roth.—Tho Common Prickly
Pern.
This is a species almost evergreen in a sheltered situation,
and one of those which are well suited by boldness of character
for the decoration of rocky scenery. It is a stout
plant, having the fronds a couple of feet long, and springing
from a stout tufted stem or crown, whence they grow up
in a circle, about the month of April, and take a somewhat
erect position. Their form is lanceolate, in the most perfect
state of the species broadly lanceolate, but in a variety
presently to be referred to, very narrowly lanceolate. The
texture is harsh and rigid, the upper surface dark green and
shining, and the short stipes densely enveloped in rust-
coloured membranous pointed scales. The fronds are bipinnate,
with alternate pinnæ, these pinnæ being again more
or less perfectly divided into a series of pinnules, which are
either decurrent, that is, insensibly merging in the substance
of the rachis which supports them, or else, are tapered to
a wedge-shaped base, and attached to the rachis by the
cnneate point. The general form of these pinnules is somewhat
crescent-shaped, for they have, as is universal in the
British forms at least of this genus, the upper base extended
into a small auricle, or enlarged lobe, and the lower base as
it were abscised; while the apex is tapered off to an acute
point, and the margin is serrated, with spiny teeth.
The veins are alternately branched, and do not join
together or anastomose, but extend free to the margin; and
the fructification, which is generally abundant, and often
crowded, is ranged in a line on each side the midrib of the
pinnules, and also on the larger pinnules on each side the
midvein of the basal lobes or auricles. The indusium is
circular, and attached by a little depression or stalk in its
centre.
A variety called lobatum, and considered a distinct species
by some botanists, differs chiefly in the narrow outline of
the frond, the pinnules of which are much more decidedly
decurrent; indeed, every possible variation in the consolidation
of the pinnules is to be met with, between the ordinary
bipinnate form of Polystichum aculeatum, and a simply
pinnate form of the species, which, from its resemblance to
P . Lonchitis, has been called lonchitidioides. This latter
form, however, owing its origin to the peculiar circumstances
of growth only, cannot properly be recognized as a variety.
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