RED SEAWEEDS 81 
stunted ; but under the shelter of rocks, in deep water, it grows in dense 
masses and is a dark purplish-red or reddish-green. Often it appears 
iridescent when seen through the water, with the sun shining on it. It 
is firm and leatheryin substance. It is an edible alga, and was formerly 
very generally used for culinary purposes. At Hingham, Massachusetts 
large quantities are gathered asan article of commerce. It isa beautiful 
and very common plant found from New York northward. (Plate XVII.) 
Genus Gigartina 
Of the species of this genus but one is found on the eastern 
coast; on the Pacific coast there are several, and they are large 
and conspicuous. 
G. mamillosa. Frond three to six inches high, one inch to two 
inches broad, flat, leathery, gelatinous ; forking near the base, then divid- 
ing and subdividing in the same plane; segments more or less wedge- 
shaped and with a tendency to roll inward; covered with numerous 
small nipple-like protuberances which contain the spores. These pro- 
jections distinguish this genus from Chondrus, which it otherwise resem- 
bles, and with which it grows. The color is dark purple. It is found 
from Boston northward. (Plate XVIII.) 
G.radula. Frond flat and thick; rising from a short stem and 
widening to several inches; sometimes tapering to the top, sometimes 
blunt or divided, sometimes cleft on the sides, but usually simple; cov- 
ered with wart-like projections; color ‘dark, livid red. It is found on 
the Pacific coast at all seasons, growing on rocks between tide-marks. 
Large specimens are one foot to three feet long and six to ten inches 
wide. (Plate XVIII.) 
G. spinosa (“thorny”). Frond thick, leathery ; surface rough and 
spiny; form variable, the divisions sometimes emanating from a broad, 
flattened base, or again branching from a main axis; all covered with 
the protruding processes peculiar to the genus; color dark red, brown, 
or purple. It is found on the California coast. -(Plate XVIII.) 
. microphylla (“ small-leaved”). Plant rises from short, flat stem, 
and rapidly expands into a flat, wide, thin frond which is simple or 
divided into two or three segments, each of which tapers into a long, 
pointed apex; thickly covered with long, slender spines, and on its 
edges bearing small, thin leaflets; color brownish-red. It is abundant 
on the California coast. (Plate XVIII.) 
Genus Phyllophora 
Leafweed. Fronds cylindrical; branched stalks which expand 
into rigid, membranaceous, simple or cleft, wedge-shaped lamine ; 
lamin bear leaflets on their edges or on their surface; spores in 
masses form projections on the surface, or are on stalks at the 
summit; color dark red. Found washed ashore from New York 
northward. 
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