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L I C H E N perlatus.
Pearly Lichen.
C R Y P T O G AMI A Alga.
G en-. Char . Male, fcattered warts.
Female, fmooth fhields or tubercles, in which
the feeds are imbedded.
Spec. Char. Leafy, creeping, lobed• grey and
tmooth above; black and hairy below; bordered
with powdery tubercles. Shields on fhort foot-
ftalks, olive-coloured, concave, with a crenate
powdery indexed margin.
Syn. Lichen perlatus. Linn. Syjt. Nat. ed. 12. v. 2.
yi2. Hudf. FI, yjn. 343* With. Hot, ^4rr. *v. 3,
205. Relb. Cant. 434. Siblh. Ox. 330. Smith's
Tour, v. 1. 225. 260.
Lichenoides glaucum perlatum, fubtus nigrum et
cirrofum. D ill. Mufc. 147. t. 10. f 39.
ƒ- O IJN D on the trunks of trees, old park pales, &c. very
frequently, but it is one of the moft rare of all Lichens in
frudMcation. Our fpecimen in that ftate was gathered in
Cardiganfhire laft fummer, and is the only Britifh one we ever
law.
The fronds fpread into patches about as broad as the hand, not
very firmly attached in any part, and the margin is quite loofe
and generally ere£t. Their upper furface is of a greyifh
white, greenilh when very much moiftened, fmooth, though a
little pitted; fometimes indeed it becomes fprinkled with
mealy cracks and tubercles intermixed with fhort black hairs.
The under fide is very black, partly fmooth and Ihining, partly
clothed with fhort black rigid branched or forked hairs, which
fometimes project beyond the margin like a fringe ; at other
times .the margin is fmooth, and chefnut-coloured, beneath.
The more elevated parts of the frond, efpecially in the centre of
each patch, are bordered with roundifh grey mealy tubercles
compared by Dillenius to pearls, by which this fpecies is
eflentially diftinguifhed from L. faxatilis, glaucus, and fome
others near it. Shields a little elevated, cup-fhaped, concave
; their difk of a greenifh olive when wet, browner when
d ry ; their margin inflexed, grey, , powdery, crenate and
lobed. Dillenius errs in defcribing the hairs of the under
furface as not branched.