M/
S P I LO M A decolorans,,
Staining Spiloma.
CRYPTOGAMIA Algae.
Gen. Char. Receptacles shapeless, without a border^
powdery, in an uninterrupted crust..
Spec. Char. Crust spreading widely, very th in , for
the most p a rt membranous, greyish white ; yellowish
green w hen rubbed. Receptacles m inute,
flat, confluent, purplish grey.
Syn. Spiloma decolorans. Turn, and Borr. Licit.
Brit. v. 1. 39.
C o m m u n ic a t e d upon the rugged bark of an old oak,
by Mr. W. Borrer. It is said to be common in that situation,
as well as on boarded buildings, and on pales.
The crust is very thin, widely extended without interruption,
even, rarely rugged or cracked, membranous, scarcely
at all tartareous ; externally of a dirty white, or grey ; green
within ; which latter hue, with a tinge of yellow, it permanently
assumes on being rubbed with any hard body. The
fructification when young appears in the form of irregular,
minute, whitish, flat, powdery warts, which soon become confluent,
covering the whole plant, and giving it a faint purplish
hue as they advance in age.
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