/ M
LICHEN ealvus.
B a ld Lichen.
CRYPTOGAMIA Alge.
Gen. Char. Male, fcattered warts. Female, fmooth
fhields or tubercles, in which the feeds are imbedded.
S pec. Char. Cruft grayifh-white, pitted, very hard.
Tubercles hemifpherical, fmooth, fcattered, of a
tawny red, without any border.
S yn . Lichen ealvus. Dickf. Crypt, fa ß . i. 18. /. 6.
ƒ. 4. Achar. Prod. 72. With. v. 4. 14. Hull. 288.
L. rupeftris. Achar. Prod. 43 ?
D i s c o v e r e d by Mr. Dickfon on calcareous rocks in
the highlands of Scotland, nor have we feen it on any other
kind of ftone. Mr. Griffith has favoured us with Welch fpeci-
mens.
The cruft is hard, and infeparable from the ftone, conforming
to all its inequalities, but not otherwife rugged, except
that it abounds with little round depreffions, left by the tubercles
when they fall off. Its colour is a pale grayiffi or
browniffi white; its furface fmooth, not at all mealy or granulated.
Sometimes it is overrun by L. niger or fome other
minute black fpecies. The tubercles are quite.feffile, hemifpherical,
hard, of a dull orange-colour more or lefs deep,
quite deftitute of any border, their furface generally quite
fmooth even and rather poliffied, but fometimes a little rugged
or uneven. Their internal part is a white core half im-
merfed in the cruft.
Mr. Turner, on the authority of Hoffmann’s fynonym,
(Verrucaria rufefcens, PI. Lich. t. 17■ f . 1 ,) has fuggefted the
probability that the L. rupejlris of Acharius, Scopoli, &c. is
the fame with this. If fo, we cannot but prefer ealvus as the
moil expreffive name. _2\P ^r f. *80/. YZMZy/hxA -ZemAhrzs