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148
THE MARINE ALGÆ OF NEW ENGLAND.
In tide-pools and just below low-water mark.
Very common from New York northward; Europe.
With the exception of Ceramium rubrum, the present is probably the most common species of Florideæ
found on our coast. It not unfrequently attains a length of a foot and a half, and when washed from its
attachment and exposed to the sunlight assumes a bright orange color, which is attractive to many
collectors. The Solieria chordalis, said by Mr. Samuel Ashmead* to have been collected in Greenland by
the Hayes Arctic expedition, was probably a sterile plant of Cystoclonium purpurascens.
GIGARTINA, Lam.x.
(From γιγαρτον [gigarton], a grape-stone.)
Fronds fleshy, cartilaginous, compressed, composed of an internal layer of
longitudinal, slender, anastomosing filaments, which pass horizontally outwards
and divide dichotomously into short moniliform filaments, the whole set in a
gelatinous substance; antheridia in superficial spots; tetraspores cruciate, densely
aggregated, forming spots just below the surface; conceptacles external.
A genus of which nearly fifty species have been described, but some of which are of doubtful value.
They abound in the Pacific Ocean, several species being found in California, but we have only one
species.
G. MAMILLOSA, Ag.; Phyc. Brit., Pl. 199.
Fronds dark purple, three to six inches high, half an inch to two inches broad,
flattish, channelled, linear, decompound, dichotomous, fastigiate, upper segments
wedge-shaped, bifid; cystocarps borne in short papillæ given off from the surface and
margin of the frond.
On rocks at Low-water mark, in company with Chondrus crispus.
Common from Boston northward; Europe.
Bearing some resemblance to the common Irish moss, with which it usually grows, but distinguished by
the numerous papillæ which cover the surface of the fronds and bear the fruit. The present species may
occur in California, but most of the specimens of G. mamillosa from the west coast belong rather to G.
papillata, Ag.
CHONDRUS, Stack.
(From χονδρος [chondros], cartilage.)
Fronds and tetraspores as in Gigartina; cystocarps immersed in the frond.
A small genus as limited by modern writers, but formerly made to include a large number of forms. The
three genera Gigartina, Chondrus, and Iridæa are very nearly related. In the first-named genus the
cystocarps are borne in external conceptacles, and in the last two they are immersed.
C. CRISPUS (Linn.), Stack.; Phyc. Brit., Pl. 63.—Irish moss.
Fronds purple, three to six inches high, stipitate, flabelliform, dichotomous,
fastigiate, flat, the segments linear-cuneate; cystocarps immersed in the frond and
usually projecting on one side.
* Proceed. Acad. Nat. Sci. Philadelphia, Vol. XV, p. 93.