The English flora - SeaweedAfrica

282 ALGtE INARTICULATiE. [Haliseris.
Marine rocks at Appin, Argyleshire, Capt. Carm'whael. Miltown
Malbay, Ireland, Mr. Harvey. Slaty and sandstone rocks near high-water
mark in Berwick Bay, Dr.Johnston.—An inch to an inch and a half broad,
the specimens often imbricated, deep rich brown, opaque. This has, at
the first appearance, a close affinity with P. (Zonaria, Ag.) squamaria from
the Mediterranean, where the fronds are often equally orbicular, but
they are woolly beneath, the substance is thinner, less opaque, and the
concentric lines are very evident. P. deusta had hitherto been considered
a native only of the extreme northern regions. " Fronds gregarious, coriaceous,
opaque, of a brownish purple colour, and marked with concentric
strise or zones, about an inch in diameter, suborbicular, flat, and adhering
firmly throughout the whole lower surface, but separating without
much difficulty. Fructification unknown." Carm. " Thin slices,"
Mr. Harvey observes, of this plant, "placed under a high power of the
microscope, appear closely cellular, with irregular polygonal meshes or
cellules, for there is no regular reticulation, like that of others of the
Genus. This species is often papillose, and much resembles a Thelephora.
I believe it belongs to a distinct genus, of which I doubt not
there are many species often overlooked as crustaceous zoophytes."
3. P.pdrvula, Grev. (small Padina) ; frond resupinate suborbicular
membranaceous deeply lobed, lobes orbicular somewhat
imbricated, scarcely at all marked with concentric lines.
Grev. Crypt Fl. t. 360, Alg. Brit.p. 63.
Rocks in the sea, near Sidmouth, Dr. GrevUle. Rocks near lowwater
mark, Miltown Malbay, Ireland, rare, Mr. Harvey. . March.—
I have not seen English specimens of this plant. Mr. Harvey, who
communicated his Irish specimens to me, observes in a letter, " Since I
have become possessed of the Cryptogamic Flora, I find by Dr. Greville's
figures, that the reticulation on our plant is different ; yet they
quite accord in habit, resembling a Marchantia, creeping by its white
radicular fibres over a space of a foot or more in extent ; sometimes
very closely attached to the rock, at others comparatively loose. In
structure, both plants are true Dictyotece. The reticulation in my plant
is less regular than in Dr. Greville's, and the meshes are shorter than
they are broad. If distinct, I propose to call mine P. decumbent."
21. Hali'seris. Tozzetti. Haliseris.
Frond flat, linear, membranaceous, witb a midrib. Root a
mass of woolly filaments. Fructification; ovate seeds, forming
distinct sori or groupes (mostly arranged in longitudinal lines).
Grev. Alg. Brit. p. 63. t. 8.—Name, aM, *M, the sea, and