This Lichen has been mistaken for L . tuberculosa, 1.1733;
but the warts of the thallus of that species are very prominent,
even, and not powdery, and the substratum is of the
same colour, not black: the scutellae also are more conspicuous,
and of a glaucous hue. In the black substratum and
in the dispersion of the warts, L . aspersa resembles Lecidea
atro-alba, t. 2336, and L ■ verruculosa, t. 2317, but, besides
the generic characters, it differs from both in the colour of
the warts and in the powdery soredia. The scutellae are
most like those of some imperfect states of L. atra, t. 949,
but the structure of the thallus is very dissimilar.—W. B.
