summer, or the necessary supply of moisture must ho applied by
moans of sjUnging. A cool shady Fern house is the proper place
in which to carry out this mode of culture. Tho fronds push out
from the basket on all sides, and have a very pleasing appearance.
This species may be readily iiicroasod by dividing tho rhizome.
There arc many delations from the typical form of this species
besides thoso which have been already briefly noticed; but they
aro chiefly of interest to tho horticultural enthusiast rather than to
the botanist; except, indeed, so far as the latter may regard them
as evidences of the mode and extent of variation to which common
species aro subject, and may hence learn to appreciate rightly the
differences which aro found to exist amongst less familiar exotic
species. I t is, therefore, chiefly for tho information of Fern cultivators,
most of whom tako an especial interest in thoso variations,
that they aro hero enumerated.
The tj’pical form of tho Common Poljipody has longish and comparatively
narrow fronds. That form of this typical series which
differs in the least degree, albeit constantly, from tbe normal state,
has tho ends of its lobes gradually tapering off to a narrow point,
instead of being equal in m d th nearly to tho end, and there more
or less blunt. Another modification has the points of the lobes
acute, but the margins are at the same time deeply notched, the
notches forming a series of coarse double serratures; in this state,
which has sometimes a tendency to furcation at the tips of the lobes,
the sori are not unusually decidedly oblong, a remarkable feature,
in which respect it somewhat deviates from the generic type.
Another slightly differing form has tho ends of some or all of the
lobes divided, with the parts spreading, so th a t tho lobes become
more or loss manifestly two-forked; or occasionally more than two
points are developed to each lobe, and we have thus an indication
of the manner in which are formed the tasselled apices which are
now found to be common among British Ferns, and even occur in
the present species.
The fronds, in some forms, moreover, acquire unusual breadth, so
as to assume a broad oblong or ovate-oblong outline; and this
departure from the typical outline is occasionally accompanied by
various degrees of marginal division in tho primary lobes, showing
a tendency towards the moro highly developed hipinnatifid varieties
represented by semilacerum and cambricum. Tho most simple condition
of this abbreviated and widened form, in which the apices
aro usually acute and tho margins finely serrated, is almost or quite
identical with the North American plant called P. virginianum, and
nearly so with tho Madeira plant called P. canariense in gardens;
it is when deeply cronato-lohato, that this type of variation, which
also sometimes varies with oblong sori, approaches the moro highly
developed or compound forms above alluded to.
We have thus indicated two different types of development among
the numerous variations of the Common Polypody. In one of these
tho narrow elongate outline of the normal form is moro or less
preserved ; and in the other, a tendency to develope breadth rather
than length, results in a frond of broad outlino comparatively short.
The constancy of the varieties, as tested hy cultivation, varies
considerably according to the mode of treatment, and depends much
upon whether they are kept confined or exposed; it is also influenced
by tbe circumstanoe of the plants being established or otherwise,
recently disturbed plants often running out or reverting to tbe
normal state, but again assuming tbe character of the variety as
they get established at the root. The only kinds, perhaps, that
are unvarying in their characters, under all circumstances, are
omnilacerum and cambricum.
Typal or oblong-fronded Series.
1. acutum (M.). This variety has the lobes without serratures,
and narrowed gradually to a longish taper point. In its most
marked condition it is not a common plant, hut is very elegant, the
fronds being rather broader than the oommbn form of the species.
Other less marked forms aro not so much tapered, and are, moreover,
shghtly serrulate, approaching towards the acute-lobod state
of the normal form. We have this variety from two localities in the
neighbourhood of Guildford, Surrey; and from ComweU, in Oxfordshire
; and Mr. Clapham reports it from Settle, Harrogate, and
Hehnsley, in Yorkshire. [Plate I I A.—Folio ed. t. I F .]
2. bifidum (Franc.) This has the lobes generally bifid or two