L I C H E N canefcens.
Grey Tree Lichen.
C R Y P T O G A M I A Alg*.
Gen. Char. Male, fcattered warts.
Female, fmooth fhields or tubercles, in which the
feeds are imbedded.
Spec. Char. Cruflaceous, fpreading; rugged and
rather leafy at the edge; of a glaucous grey.
Shields central, deprefled, black, with a narrow
blackifh border.
Syn. Lichen canefcens. Dick/. Crypt, fafc. i. io.
t. i . f 5. With. v. 4. 9. Sibth. 324.
L. incanus. Relh. 424.
Lichenoides cinereum, mere cruftaceum, eleganter
expan fum. Rail Syn. 71.
L. cruftofum orbiculare incanum. Dill. Mufc. 135.
t. 18. ƒ. 17 A.
Mr. DICKSON firft, of all our late fyftcmatic authors, de-
fcribed this common fpecies, which though extremely frequent
on the barks of old trees, being rarely found in fructification,
had been generally overlooked for L. pallefcens.
It grows in a cruftaceous manner flat upon the bark, forming
patches, which often meet and run into each other. When
feparated with a knife it is found to be meally, pliable and
fomewhat leafy towards the edge, its inner fubltance very white,
the under fide fometimes of a delicate pale flefh-colour. The
upper fide is concentrically rugged, of a light glaucous grey, not
fhining, often fprinkled with white powdery fpots, which Dil-
lenius, perhaps rightly, confiders as the male pollen; but he
errs in believing it to be always produced on diltinCt plants
from the fliields. The latter are very rarely found, and pnly
on the oldeft plants, growing cluttered in the middles, part.
They are flat and deprefied, blackifh, with a narrow, rather
paler, margin.
Mr. D. Turner obferves that when growing on walls or
roofs it often decays in the centre, or is centrifugous.
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