C la s s a n d O r d e r CRYPTOGAMIA ALGA:, Linn ^Na t . O r d . ALGAE, Jttss.
GEN ERIC c h a r a c t e r .
Frons cariilaginea, dichotoma, angustissima, tiiherculis terminalibus.
Frond cartilaginous, dichotomous, very narrow, with terminal tubercles.
s p e c i f i c c h a r a c t e r .
L i c h in a pygraasa; fronde plana, tuberculis globosis.
L. frond plane, the tubercles globose.
L i c h in a pygm^a, Agardh, Sp. Alg. p. 105.—Syst. p. 274.—Hook. FI. Scot,
p. 96- (var. a.)-~Grev. FL Fdin. p. 286.
G e l id u m pygmieum, Lyngb. Hydroph. Dan. p. 41. in part.
F u cu s pygmaeus, Lightf. FI. Scot. p. 964. t. 32.— With. Bot. Arr. ed. 6. v. 4.
p. 118.— Turn. Syn. Fuc. v. 2. p. 258.—Not. Fngl. Bot. t. 1332.— Turn.
Hist. Fuc. t. 204. f. a,-h, (var. a.)
Fucu s pumilus, Huds. FI. Angl. p. 584.—Fsper, Ic. Fuc. 2. p. 9. t. I I 6.
Fu cu s lichenoides. Good. ^ Woodiv. Linn. Trans, v. 3. p. 192.—Hull. FI. p. 324.
L i c h e n saxatilis maritimus muscosus minimus nigerrimus, Mich. Nov. PI.
Gen. p. io3.
H ab. Rocks in the sea below high-water mark, freq u en t; in Scotland most
plentiful in the north. In England very abundant on the south-west
cbast. Perennial; producing perfect fructification in autumn.
Plant growing in a crowded manner, often entirely covering the rocks,
of a very dark dull green colour when moist, quite black when
dry. Root an irregularly dilated disk, very evident where the fronds
are not densely crowded. Fronds cartilaginous, very numerous, forming
somewhat spreading tufts, which becoming more and more confluent,
press each other into a more erect position: they rarely exceed
h a lf an inch in length, are much compressed, or plane, repeatedly divided
in an irregularly dichotomous manner, not half a line broad, towards
the apex generally more or less palmated, the branches speading,
the summits obtuse. Fructification subglohose tubercles terminating
the fronds, or situated near the apex, often clustered together, of a dark
dingy yellowish colour towards their pore-like orifice: they are filled
with a fine gelatinous mass, which, when divided horizontally, exhibits
the oval seeds or sporules, lying among dense filaments, and arranged in
nearly continuous lines from the centre to the circumference. After the
escape of this mass, the tubercles begin to decay, and, by the enlargement
o f the orifice and gradual disappearance of its mai-gin, assume the
form of the sliields of some lichens.
vol., IV.