paler brown, tinged in different plants with yellow, green,
or grey, and often obscured by a greyish film. The tuber-
çles vary much in size, being occasionally as large as rape-
seed, but usually much smaller. They are completely immersed
at first, and sometimes even when full grown ;
the crust forming little protuberances above them ; more
usually they gradually emerge, and are sometimes polished
and of a full black, sometimes brownish or greyish, as if covered
with film. A small grey dot marks their apex. Their
nucleus when wet is dark grey and gelatinous, and fills
the shell : in drying, it shrinks much and becomes black.
The shell incloses it on all sides ; hence the plant is a P y -
renula of Acharius.
V. maxima of the Flore Française is this species with tubercles
of the largest size.—W . B.
2607. (Fig. 2.)
V E R R U C A R I A dermatodes.
Vellum-like Verrucaria.
CRYPTOGAMIA Lichenes.
Gen. Char. Tubercles of a different nature from the
thallus, simple, convex, not expanding, but furnished
with a central pore, and inclosing a somewhat
gelatinous nucleus.
Spec. Char. Crust determinate, between filmy and
tartareous, continuous, very smooth, cream-coloured,
swelling about the tubercles. Tubercles
hemispherical, black, immersed; at length exposed.
J _____
F O U N D on trees in Ireland; near Bantry by the late
Miss Hutchins, and near Killarney by the late Sir T. Gage,
Bart. It grows in patches of considerable extent, bounded
by a narrow black line. Miss Hutchins observed the living-
plant to be constantly suffused with a reddish tinge, probably
of an extraneous nature, of which some traces remain
on our long-dried specimens.
This Lichen, particularly in the state figured at b (which
we presume we are correct in regarding as the same species
as that at a), is very liable to be confounded, by a hasty
observer, with V. epidermidis as it usually grows on birch-
trees, and still more with a variety of similar hue which
sometimes spreads widely over the trunks of young ash-
trees in woods. In the real nature of the crust, however,
and the formation of the tubercles within it, the present
species much more resembles V. nitida, although not in the
structure of the tubercles, the shell of which does not, as in
that, inclose the base of the nucleus. From that Lichen
the colour, and the remarkable vellum-like appearance of
its thinner and polished crust, distinguish it at first sight.
The entire want of dots on the surface affords also,