CRYPTOGAMIA Alga.
G e n . C h a r . Ma le,Sc attered warts. Female, fmooth
ftfields or tubercles, in which the feeds are imbedded.
S pec. Char. Cruft white, teflellated as if fomewhat
imbricated. Shields uniform, round, convex,
blackifh, clothed with fine grey mealinefs, and
bordered with white.
Syn. Lichen epipolius. Achar. Prod. 58.
O b s e r v e d by Mr. Turner growing on calcareous ftones
in feveral old buildings in Norfolk and Suffolk. This fpecimen
came from the church of Market Dereham. We know of no
other botanift who has found this Lichen in Britain, nor has
it been noticed by any writer except Dr. Acharius. Although
fine fpecimens of it are not always to be found, and therefore
it may be overlooked, it is a perfectly diftin& fpecies.
The cruft, when not impeded, fpreads circularly, and is of
a fine tartareous texture though thin, pure white within,
externally when moift faintly tinged with grey; it is finely
cracked or teflellated, and towards the margin a little lobed,
but fcarcely imbricated or rugofe. Shields numerous, feflile,
final!, uniform, exa&ly round, convex, clothed with a filvery-
grey mealinefs, which is with difficulty rubbed off, and leaves
the fliield almoft black. When young each fhield has a narrow
white border.