formed filaments than at the base of the plant, dotted from the
presence of minute granules: joints about twice as broad as
long, the terminal one somewhat dilated and hemispherical.
The branches towards the base of the plant are seated each
upon a connecting cell of an ovate or cordate form, resembling
those in the genus Rimdaria and the filaments of the Nosto-
chinecE. As to their true function we are unable to satisfy
ourselves, though we quite agree with Mr. Ralfs in considering
them totally distinct from sporangia. The plant
possesses other branches, formed, as Mr. Ralfs truly observes,
by a dislocation of the endochrome, each separated
portion becoming elongated, the lower portion towards the
apex of the plant, and the upper portion towards its base,
and each parallel and coherent with the other, and not usually
separating until another dislocation has taken place in the endochrome
of one of them, so that the filaments cohere mostly
in pairs throughout the plant, though sometimes four or more
filaments are coherent within one common sheath. He also
remarks that the apparent branch (which is really a portion
of the original filament) always extends beyond the filament
from which it appears to be given off.
The sheaths of both the British species of Desmonema have
commonly numerous minute papillary or clavate bodies upon
them (fig. 5). We are unable to satisfy ourselves whether
these bodies represent the anastomosing rootlets of Rhizonema
(see t. 2954) and the numerous delicate fibres intermixed with
the filaments of Caluthrisc fasciculata and other species, or are
altogether extraneous to the plant; we are inclined to the
latter opinion.
D. cirrhosum differs in having much denser sheaths to the
filaments, and in the secondary branches being most frequently
included (several together in one common sheath) as in Cceno-
coleus.
Found on mosses in a rapid mountain rivulet, Cader Idris,
August and September, by Mr. Ralfs; on moist rocks, Co.
Antrim, by Mr. Moore; on rocks at the head of the Swansea
valley, by Mr. Motley.—M. J. B. and G. H. K. T.
Fig. 1, plant natural size; fig. 2, slightly magnified; fig. 3,
portion from near the base (Mr. Thwaites’s drawing); fig. 4,
near apex; fig. 4 a, ditto still more magnified; fig. 5, portion
of the lower part covered with the minute clavate bodies.