90 MARINE ALG 
tiful alga of a red-brown color. It is found washed ashore, or in deep 
tide-pools, south of Cape Cod. (Plate XXIX.) 
BR. larix. Frond cylindrical, robust, six to fourteen inches high; 
branches of unequal length standing out horizontally all around the main 
stem ; clusters of branchlets growing spirally around stem and branches. 
Found on the northern California coast. (Plate XXIX.) 
R. floccosa. Frond four to ten inches high; less robust than R. 
lariz ; stem and branches flat and divided in one plane ; branches alter- 
nate; ultimate branchlets somewhat incurved; color black. In fertile 
plants the terminal branchlets are gathered in a mass. Found on the 
California coast. (Plate X XIX.) 
Genus Chondria 
Plants of this genus are distinguished by having the ultimate 
Be sien attenuated at the base. 
C. dasyphylla. Frond four to eight inches high; general outline 
pyramidal; branches alternate on main stem; stem and branches cov- 
ered with short, club-shaped (blunt at top, attenuated at base) branch- 
lets; cystocarps, or spore-cases, adherent to branchlets or on short 
stalks; color light or dull brown. It grows in tufts, and is common 
from New York to Cape Cod. (Plate XXX.) 
C. tenuissima. This species is similar to C. dasyphylla, but is more 
sender) and the branchlets taper at both ends instead of being club- 
shaped. 
. striolata. A species similar to C. tenuissima. The branchlets 
bear secondary branchlets, and the cystocarps are on short stalks. It is 
plentiful in Long Island Sound. 
SUBORDER CERAMIEE 
Genus Callithamnion 
These are very beautiful and delicate plants, growing in small, 
soft, silky tufts, bright red in color, with darker dots along the 
much-branched filaments. There are many species, and they are 
common on the northern shores of both oceans; but the different 
species are not easy to distinguish with the naked eye, and so but 
a few of them are described below. The special characteristics by 
which the genus may be recognized are: fronds filamentous, of 
cobweb fineness, one inch to six inches long, much branched, 
and closely crowded at the top; brilliant red color. 
C. americanum. Frond three to six inches long, densely tufted ; 
filaments of extreme fineness; main branches alternate ; much branched ; 
main and secondary branches have pairs of branched ramuli along the 
