il
represented in Plate XYII. The general form is ovate, a
little elongated ; that of its pinnæ (the secondary pinnæ)
narrow lanceolate. These latter are placed rather closely
together, and are again divided into a series of pinnules.
Two forms will be met with, one apparently equally common
with the other : in one the pinnules are undivided, and attached
to the rachis by their base without the intervention
of any stalk, and these bear a line of spore-cases along each
margin ; in the other the pinnules are larger, more elongated,
and deeply pinnatifid or sinuate, the margins of these lobes
bearing the lines of spore-cases. The apices of the primary
and secondary pinnæ, and of the pinnatifid pinnules, become
less and less divided, until at last the extreme points form
an entire lobe, more or less elongated.
In its venation there is some variety, dependent on the
differences of structure and development which we have
already pointed out. We shall he most intelligible by explaining
the form represented in Plate X Y II., which shows
the least divided form of the plant. Each pinnnle, as is
there shown, has a distinct midvein, producing alternate
lateral venules, which become twice forked, and extend to
the margin, where they meet a longitudinal marginal vein
which forms the receptacle. The indusium consists of a
bleached, membranous, fringed expansion of the upper skin
or epidermis of the fronds, which reflexes so as to cover the
spore-cases, but there is here another membrane which lies
beneath the spore-cases, and is no doubt a similar expansion
of the skin of the under surface.
It has been already remarked that there are two forms of
this plant commonly met with. These are so very dissimilar
that we have elsewhere* proposed to distinguish them as
varieties, applying to the pinnatifid form the name vera, and
to the more entire form that of integerrima.
This, which is the most abundant of our indigenous
species, is also widely distributed in other parts of the world,
and hears a variety of names, from having been supposed to
be distinct by those who have met with it from such widely
separated localities.
Being so common, and in an ordinary state unconth-
looking, it is not a plant for cultivation to any extent. In
warm, damp wilderness-scenery, however, where it would
attain great luxuriance, and the situation is such as would
enable it to develope the arching character already mentioned,
it might very properly be introduced.
fl
* Handbook of Britisb Ferns : p. 134.