which are separate from each other. The pinnæ are narrow
and tapering, with a few of the lowest pinnules distinct, the
rest united at the base ; these pinnules are of an obtusely
oblong form, and serrated on the margin. The fructification
of this plant' is generally very copious, and is usually confined
to the lower half of the pinnules, where it is crowded.
This is one of the best species to study with the view of
understanding the fructification of Ferns, for here the indusium,
a very important organ, is seen to be remarkably prominent
in fronds which have about reached their full deve-
opment. In that state the indusium is as yet closed over
the clusters of spore-cases, and will be seen to consist of a
lead-coloured, tumid, kidney-shaped, conspicuous scale,
which, at the proper time, becomes elevated on one side to
allow the dispersion of the spores. This may readily be seen
by closely watching the progress of the fronds after they
have reached the stage just adverted to ; or if they are
gathered in that state for preservation in the herbarium they
are ahnost certain to burst, more or less, in the process of
drying, before they yield up their vitality. These covers are
at first little white scales.
The veins of this species are also readily seen, and each
pinnule wiU be found to have a flexnous midvein, with