larly roundish, separate or confluent, flattish at the edges,
which are irregularly sinuated or crenate, but with turgid
granulations on the surface; their hue a dark obscure green,
or almost black. Scutellae formed within the substance of
the lobes, mostly solitary, appearing at first a mere depressed
dot, which gradually expands into a disk of the
same hue as the thallus, or more or less tawny, at length
occupying nearly the whole width of the lobe, which forms
about it a thick, obtuse, orbicular margin, entire, or occasionally
a little crenulate, sometimes level with the surrounding
portion of the thallus, sometimes rather elevated
above it, the disk itself being flat or slightly concave. In
drying the thallus changes entirely its appearance, becoming
a thin black or bluish crust which scarcely rises at all above
the level of the soil, and in which the disks of the scutellm
form slightly concave, red, orbicular depressions. Moisture
however, as usual in this tribe, restores the original appearance,
even after the specimen has been kept dry many years.
The near affinity of this little Lichen to Collema cristatum,
(Lichen crispus of Engl. Bot. t. 834.) is obvious, and it may
possibly be but a variety; yet the scattered mode of growth,
and the less tenacious substance of the thallus, which almost
disappears in drying, seem to indicate a specific difference.
As in other instances among the Lichens, so in that of
this, at first view, mostcc natural and distinct” genus, we
are far from being satisfied as to the generic character. We
have adopted one from Acharius, without being able heartily
to subscribe to it. His microscopic investigations we have
not verified. Bernhardi has justly observed*, that the °e-
latinous and bibulous nature of the thallus is but comparative,
variable among the species of this genus, and partaken
in various degrees by Lichens of other genera; and we could
almost wish with that writer, that, with the exception of a
few obvious genera, such as Opegrapha, Gyrophora, Verru-
caria, Calicium, the Lichens were re-united as a single ffenus
—W .B . 6
* Lichenum gelatinosorum Illustratio, in Schrader’s Journal for 1799
pt. 1. p, 2.
2704 (Fig. 2)
COLLEMA ceranoides.
Horned Collema.
C R YPTOGAMIA Lichenes.
Gen. Char. Apothecia scutelliform, (immersed, sessile,
or somewhat stalked,) formed entirely of the
thallus, and of a homogeneous substance without
and within, subcartilaginous when dry, subgela-
tinous when w e t; margin and disk of the same,
or, sometimes (when dry) of different colours.
—Acharius.
Spec. Char. Lobes of the thallus imbricated, ascending,
pulpy, dilated upwards, proliferous, terminated
with crowded erect elongated granules
overtopping the flattish scutellae.
Syn. Collema palmatum a. Ach. Lich. Univ. 643 ?
Syn. 319 ?
D r a w n from fine specimens found by Mr. R. J . F.
Thomas at Boxgrove, near Chichester. The species is not
uncommon on the chalky soil of the Sussex Downs, but
does not generally produce its scutellae. Mr. Forster has
gathered it at Henham, Essex.
Thallus gelatinous, olive-brown, tinged but slightly in
general with green, in young plants often blackish, growing
in roundish pulvinate patches, sometimes half an inch thick;
lobes proliferously branched, flabelliform, or dilated upwards
from a narrow and sometimes almost cylindrical base,
terminated by numerous turgid, graniform,or elongated and
subcylindrical, erect, fastigiate, crowded laciniae, proceeding
chiefly from the edges, but some of them from the disk,
of the lobes, which in most instances they entirely conceal,
and forming the surface of the patch. Scutellas sessile on