LICHEN parasemus.
Common BIcick-shielded Lichen,
CRYPTOGAMIA Algae.
Gen. Char. Male, scattered warts.
Female, smooth shields or tubercles, in which the
seeds are imbedded.
Spec. Char. Crust thin, greyish, uninterrupted, some,
what granulated, black-edged. Shields sessile, flat,
opaque, black, with a black smooth b o rd er: at
length convex.
Syn. Lichen parasemus. Ach. Prod. 64. Relh. 4S3.
L. sanguinarius. Lightf. 803. Sil'th. 320. HoJJin.
Enum. 2 1. t. 5 .f . 3, 4.
Lichenoides leprosum, crusta cinereo-virescente, tu-
berculis nigerrimis. Dill. Muse. 126. t. 18. f . 8.
Rati Syn. 1 \.
Lecidea parasema. Ach. Meth. 35.
O n E of the most common of all Lichens on the smooth
bark of trees, closely intermixed with L. subfuscus and some
other thin-crusted species, from the patches of which it is
distinguishable by its greener grey colour, and a thin black
line which marks its edge. Hence Scopoli called it limitatus,
a name which perhaps ought to have been retained. We
nevertheless, to avoid controversy and confusion, adopt that
of Dr. Acharius, which expresses the vulgarity of the species.
Few indeed are more frequent or less attractive.
The crust is thin, and inseparable from the bark, slightly
rugged and cracked, pale greenish grey with an uneven (generally
black) edge. Shields numerous, irregularly crowded,
small, sessile, but not at all sunk into the crust, of a deep dull
black: when young flat or rather concave, with a smooth
black border: when old convex, rugged, without a border.
Being formed in winter, and lasting for a year or more, the
shields (by the stretching of the bark) are often separated
into oblong clusters. They are grey, not red, within.
Most authors have confounded this with sanguinarius, see our
v. 3 . p. 155, where it is alluded to as “ growing on smooth
young t r e e s . r