CRYPTOGAMIA Alga.
Gen. Char. Male, scattered warts.
Female, smooth shields or tubercles, in which the
seeds are imbedded.
Spec. Char. Crust spreading, very thin, smooth, even,
pale glaucous. Shields sessile, flattish, black clothed
with grey powder; their margin black.
Syn. Lichen abietinus. Ach. Prod. 57. Stochh. Trans,
fo r 1795. 139. t. 5 . f 7.
Lecidea abietina. Ach. Meth. 54.
T h i s grows on the bark of different species of Fir, sometimes
on the dead wood. It has been found in the north by
Mr. Dickson and Rev. Mr. Harriman, and in Suffolk by the
Rev. Mr. Leathes. Our British specimens agree with those
sent by Dr. Acharius, who alone has described this species of
Lichen.
The crust is extremely thin and uniform, spreading indeterminately
over the wood and inseparable from it, of a very
pale greenish grey, smooth, or slightly powdery, in which
last case it is whiter. Shields scattered, sessile, black ; when
young minute, but perfectly formed, with a flat disk, which
in time rises somewhat in the centre. The disk is more or
less clothed with a fine grey mealiness, which easily rubs off,
and leaves the disk black. The border is elevated, uniform in
breadth, rounded, black, at length flexuose, and in some
measure crenate.