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and is so thinly clothed with scales as to appear naked; whilst the
leafy portion or lamina is comparatively short, being sometimes not
more than an inch, rarely exceeding throe or four inches long; the
base is cordate, the apex obtuse, the margin more or less undulated
lobed or contracted, and laoiniately or crenately toothed. Tho
fronds aro more or loss but irregularly marginate, most so towards
the apex, whore, at the termination of the costa, there is frequently
formed by the epidermal development, an irregular pouch or
pocket, as in peraferum (77). Tho costa on the upper surface is
raised, and broken up into little irregular exourrent points, producing
a muricate, or almost echinate ridge; and on tho under side it
frequently becomes exourrent in the form of a horn. The fronds
are fertile in the upper portion, and the pouch is also fertile. This
was found in Ireland by Dr. AUehin, and is a permanent interesting
and unusual form.
79. nudicaule (Allchin). The fronds of this exceedingly rare form
arc variable, being narrowish, cordate at the base, simple or multifid
at the apex, short or elongate, some of them pocketed, some
marginate. The chief peculiarity of this variety, however, consists
in the almost total absence of scales, a condition very unusual in this
gonus, but here so strongly marked, that in the vernation of tho
plants, the convolutions of the fronds which are to he developed for
several years onwards are visible on tho crown. Tho plants resemble
rugosum (78) in their peculiar smooth appearance, but otherwise
are quite distinct. It was found by Dr. AUchin in Ireland.
80. sieiforme (WoU.). This is the most slightly marginate of the
varieties referred to the marginatum group, and is not always constant.
The fronds are narrowish, less than a foot in length, and about an
inch wide, subcordate at the base, lanoe-shaped, having somewhat
floxuous or lateraUy waved margins which are sUghtly crenate, and
ohsoletely, though continuously, marginate beneath ; the apex being
bluntish; they are also supra-soriferous, but the upper sori are very
smaU. It was fonnd in Guernsey by Hr. 0. Jackson.
81. scabrum (AVoU.). This is a very handsome variety, somewhat
intermediate between the marginatum and muricatum grojjps. The
whole plant is of vigorous growth, with fronds upwards of two feet in
length, and nearly two inches broad; the base cordate or truncate
and sublaoiniate, the apex attenuate ; the margin irregularly cre-
nate-lobato, somewhat undulated. They are suhmarginate beneath,
and suhmuricate towards the margin above, tho face of tho frond
being uneven, hollowed out hero and there into cavities, hounded
by raised lines and points, so as to become almost interruptedly
supralineate. The fronds are less affected in the lower half, being
there only slightly crenato ; they are abundantly fertUe, and somewhat
suprasoriferous. It was found in Ireland, in 1853, by Dr.
Allchin, and is a singular and rare as well as handsome variety.
82. himarginatum (AA'olL). This is one of the most curious
varieties yet known, and forms a very handsome plant. The fronds
are sometimes narrow, from about a quarter to half an inch wide,
and about six inches long oxoluding the scaly stipes ; others are three-
quarters of an inch wide, and from six to nine inches long. The
base of the fronds is truncate, often broken up into a few
separate lobes ; the apex is either simple or multifid ; the edges are
laoiniate-toothed or broken up into narrow shallow truncate lohes,
which are bifid or toothed ; and the surface both above and below
is marginate, the fronds thus becoming bimarginate. The excurrent
membrane forming tho margination, appears on the under side, as
in other marginate forms ; hut on the upper surface, the cuticle is
very irregularly broken up, the membranes hoing gathered and
puckered so as to form cavities and excrescences, while the
few lower separate lohes not unfrequently spread into small calyci-
form or trumpet-shaped bodies tapered to a stalk-like base. The
tip of the frond whether simple or divided, is generally somewhat
less obviously marginate, and sometimes a Kttle broader. The
autumnal fronds are broader and irregular on the margin. It
seems a somewhat tender variety, and does not perfect its spores
so freely as many other kinds. Tho original plant was fonnd near
Eothorham, in Yorkshire, by Air. H. HayKng, gardener to the Eev.
AV. Hudson, of St. Catherine’s, Eegent’s-park ; and this form is not
unfrequently multifid. Others having the same general characters
have been found by Air. J. E. Cobb, on a bridge near Brecon ; and
by Air. Hadwin at Ulverstone : the latter being a finely multifid-
lobate plant, apparently constant. Air. Elworthy has raised the
same form from spores.
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