LICH EN fluviatilis.
River Gelatinous Lichen.
CRYPTOGAM1A Alga;.
G en. Char. Male, scattered warts.
Female, smooth shields or tubercles, in which the
seeds are imbedded.
Spec. Char. Gelatinous, thick, imbricated, greenish-
black ; its segments obovate or linear, convex, proliferous,
channelled beneath. Shields globose, concave,
brown.
Syn. Lichen fluviatilis. Huds. 536. With. v. 4. 77.
Hull. 301.
Lichenoides gelatinosum, foliis angustioribus tuni-
formibus. Dill. Muse. 142. t. 19. f . 2 8 .
L. gelatinosum opuntioides. Dill, in Raii Syn. 72.
Parmelia? fluviatilis. Ach. Meth. 2 4 9 .
M a l h a m -c o v e in Yorkshire afforded this rare plant to
Dr. Richardson, the friend of Dillenius, and from the same
romantic and celebrated spot our specimens were obligingly
communicated by Samuel Hailstone, Esq. It grows on calcareous
stones in the rivulet which issues from the base of
the-surrounding rocks. Dillenius relates that he had himself
gathered the same in the alpine torrents of Snowdon.
The fronds are of a very dull dark olive, almost black,
tufted and crowded, gelatinous, but thick and not membranous.
Segments more or less imbricated, oblong, or more
frequently obovate, occasionally notched; convex above;
channelled underneath. They grow in a proliferous manner,
and are sometimes granulated. Shields lateral, small, globular,
externally like the frond in colour, with a paler smooth border,
and concave reddish-brawn disk.