2721
COLLEMA microphyllum.
Small-lobed Collema.
CRYPTOGAMIA Lichenes.
Gen. Char. Apothecia scutelliform, (immersed, sessile,
or somewhat stalked,) formed entirely from
the thallus, and of a homogeneous substance
without and within, subcartilaginous when dry,
subgelatinous when wet; margin and disk of the
same, or sometimes (when dry) of different,
colours.—Acharius.
Spec. Char. Lobes of the thallus crowded, imbri-
crated, minute, pulpy, much divided ; ultimate
segments roundish, crenulate, somewhat convex.
Scutellae sessile, with a raised entire margin ; at
length flat.
Syn. Collema microphyllum. Ach. Lich. Univ. 630.
Syn. 310.
D i s c o v e r e d by the Rev. G. R. Leathes, on elm-
bark, near Bury St. Edmund’s, Suffolk, and communicated
thence by Mr. Dawson Turner to Acharius, who has commemorated
the species as occurring also in Sweden, France,
and Switzerland.
Thallus spreading irregularly, appearing, to the naked
eye, a rugged, dark, greyish brown crust, blacker with a
tinge of green when wet; but found, when magnified, to be
composed of closely imbricated lobes, of uncertain figure
and variously divided, with an uneven surface, as if powdered
or minutely granulated and cut at the edges into
small, rounded, crenulate, flattish or convex segments:
substance hard and opaque when dry; when wet subgelati