shrinking much and rather darker when dry, varying much
in quantity, and often wanting in some parts and clustered
in others, but not particularly, in our specimens, towards
the edges of the lobes. Scutellse numerous on the two
specimens on which we have seen them, affixed by the
centre only, and almost stalked, about the size of cabbage-
seed ; their disk red, at least when the plant has been
dried; their margin entire, or very minutely crenulate,
indexed in an early stage, afterward narrow and almost
level with the flat or somewhat convex disk.
The substance of the thallus of this species is about as
thick as that of C. crispum, whilst its lobes are larger and
less divided, and its scutellse considerably resemble those of
C. granulation, t. 1757, and C. Jiaccidum, t. 1653 : but the
thallus is much less thin and membranous than in the
latter, the lobes less entire, and the granules not so numerous
nor so minute: the lobes are less concave than in
C. granulatum, and the granules are confined to the upper
surface, and the tufted cottony radicles are wanting. Judging
from the specimen sent by Acharius to the Linnean
Society, C. thysanceum of that author is scarcely more than
a variety of C. dermatinum. Whether C. prasinum of Hoffmann,
and Lichen pulcher of Leers, cited with doubt
by Acharius, are the same or not, we have no means of
knowing.
Dillenius records his Lichenoides, no. 22, as foundfirst on
rocks near Wetzlar, and subsequently at Marston near
Oxford. It can scarcely be doubted that his figure and
description belong to the Collema before us - and it may be
conjectured that they were made from the German plant,
and that the specimens preserved in his herbarium, which
are C. granulatum, were gathered at Marston, and erroneously
regarded as the same species. Wulfen (in Jacq.
Coll. v. 3. 132.) refers to this figure of Dillenius, as a
representation of his own Lichen submarginalis; but the
situation that he ascribes to his Lichen, on clayey soil
among Riccia glauca, Phascum piliferum, See., and his
remark that, in drying, “ imbibitum velut a terra disparet,”
can scarcely apply to the present species, and rather countenance
the opinion of Bernhardi, that the plant was probably
a Tremella. Lichen rupestris of Withering was
intended for the Marston plant; and the account of it is a
compilation from Jacquin and Dillenius.—W.B.