creeping stem, which often forms densely matted tufts.
They are quite smooth, and of a bright light green colour,
supported by stipes which are usually about twice as long as
the leafy part, and are slender, brittle, and dark-coloured.
The outline is almost pentagonal, the frond being divided
into three branches, each of which is of a triangular form.
One peculiarity about this species, which is in a slight degree
shared by its near ally, P . caloareum, is the deflexion of the
rachis at the point where the lateral branches of the frond
take their rise, but this feature is greatly more obvious in
P. Pryopteris. The fronds are divided thus :—each branch
is pinnate at the base, and pinnatifid towards its point ; the
pinnæ are also pinnate at their base, then pinnatifid, becoming
acute and nearly entire at the point ; the pinnules and
ultimate lobes are oblong and obtuse. The pair of pinnules
at the base of each pinna, close to the principal rachis, are
placed so that when the pinnæ are exactly opposite they
stand in the form of a cross ; the two towards the apex of
the branch being smaller than the opposite pair, and more
nearly parallel with the rachis.
The pinnules or lobes have a rather tortuous midvein,
from which the venules branch out alternately, being, in
those of moderate size, simple, with a sorus near their ex