LICHEN cyrtellus.
Tumid Brown-shielded Lichen.
CRYPTOGAMIA Algce.
G e n . C h a r . Male, scattered warts.
Female, smooth shields or tubercles, in which the
seeds are imbedded.
S p e c . C h a r . Crust very thin, continued, smoothish,
glaucous-white. Shields scattered, small, sessile,
brown, with a lighter border o f their own substance
; at length hemispherical, blackish, the border
disappearing.
Syn. Lecidea cyrtella. Ach. Meth. 67- Winch v. 2 . 38 ?
We presume this may have been overlooked in an early
state for L. sulfuscus. t. 2109, from which it differs in being
a Lecidea; and in a more advanced one for parasemus,
t. 1450, from which it is known by its far less black, less numerous,
and less convex shields, whose border when young
is almost white, not coal-black. We know not of any other
species with which it can be confounded. We have this
Lichen from Mr. Turner, Mr. G. Don and Mr. Borrer,
found in their several neighbourhoods, so that it appears to be
not very rare.
The crust is thin, but constant and continued ; rather glaucous
and mealy when young; subsequently smoother and of
a pure white. Shields small, scattered, sessile; their young
disk flat, narrow, light-brown, with a thick, smooth, still
lighter-coloured border of the same substance, which becomes
blackened, thinner, and at length nearly obliterated by age,
when the disk grows singularly convex, and brownish-black.
Some shields are lobed or compound, as in L. sulfuscus,
t. 2109, e.
BSiggSpï,,