RED SEAWEEDS 89 
and dividing rapidly, forming a densely tufted mass, which collapses 
when taken from the water; color purple-brown; when mounted, silky 
in appearance; filaments banded; siphons six in number. It forms 
purple tufts on woodwork and on eel-grass from Cape Cod southward. 
BP. Woodii. Fronds four to six inches high; branches flat, long, 
wide-spreading, emanating from the edges in one plane; younger 
branches show articulations; ultimate branchlets inclined to curve in- 
see 7 le light brown. Found on the California coast. (Plate 
Genus Laurencia ‘ 
L. pinnatifida. Frond flat, thick, leathery; main stem with oppo- 
site, or alternate, branches of about the same size and character as 
itself ; all pinnatifid, or cut on the edges into branchlets, some of which 
are again divided; color bright purple, often unevenly faded. It is 
found on the Pacific coast. (Plate XXVIII.) 
Genus Dasya 
Chenille-weed. 
D. elegans. Fronds from six inches to three yards long; main stem 
and branches cylindrical, and all densely clothed with a fine, hair-like 
fringe, which gives the plant the appearance of chenille; cystocarps on 
stalks along the branches; color pink or lake-red. Out of water it 
seems like a mass of purple jelly. It is found at or just below low-water 
mark from Cape Cod southward, and is very plentiful in New York Bay. 
(Plate XXVIII.) 
D. plumosa. A species found on the California coast. The fringe 
covering the stems consists of minute leaflets instead of hairs, as in 
D. elegans. (Plate XXVIII.) 
GEenus Bostrychia 
B. rivularis. Fronds one inch high; color dark purple; branches 
fine and irregularly bent. It grows where the water is not very salt, and 
is found in patches on submerged logs near New York. Common from 
Charleston, South Carolina, southward. (Plate XXIX.) 
Genus Rhodomela 
R. subfusca.. Frond six to eighteen inches long; main stem cylin- 
drical, and branching widely on all sides; branches longest at base and 
_ gradually shortening to the top of the stem; branches naked below, but 
at the ends profusely branched, forming tufts of branchlets. It is a 
perennial plant, and changes in aspect with the season. When mature 
it is stiff and coarse, and when dry it is quite black. Common from New 
York northward. . 
R. Rochei. This species resembles in form R. subfusca, but is much 
finer and more delicate. Inspring it is a soft, fine, feathery, and beau- 
