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128
THE MARINE ALGÆ OF NEW ENGLAND.
Fronds globosely tufted, One to three inches high, filaments very delicate, slightly
corticated at base, main branches many times divided, secondary branches long and
flexuous, pinnate with numerous pinnately compound branchlets; antheridia sessile
in tufts at the nodes of the branchlets; tetraspores tripartite, sessile on the upper
side of branchlets; favellæ binate on the upper branches.
Var. UNILATERALE, Harv.
Fronds small and very delicate, branches and branchlets often secund.
Var. FASTIGIATUM, Harv.
Branches fastigiate, the lesser ones densely ramulose at the tips.
Var. WALTERSII, Harv.
Upper branches distichously compound-pinnate, branchlets patent.
On Zostera and different algæ.
Common in Long Island Sound; Gloucester, Mass.
The forms which have been referred on our coast to C. byssoideum and C. corymbosum are hopelessly
confused. Although as described by algologists the two species are sufficiently distinct, in practice it is
difficult to say where one begins and the other ends. According to the books, the ramification of the
upper branches is dichotomous in C. corymbosum, whereas it is always alternately pinnate in C.
byssoideum. In some of the forms of the last-named species, however, the tips are corymbose and the
cells of the axis are short and zigzag to such a degree that the tips at least appear to be dichotomous. Of
the two species in question, C. corymbosum is the less delicate and gelatinous, and is not so decidedly
rose colored as C. byssoideum, but, as far as our present information goes, although in its typical form
C. byssoideum is not only common—apparently more common than in Europe—but also easily
recognizable, its extreme forms are not sufficiently well known. The Kützingian method would be to
split the species up into four or five new species. According to Crouan and Bornet, this species has
seirospores.
C. CORYMBOSUM, (Engl. Bot.) Lyngb. (C. corymbosum, Phyc. Brit., Pl. 272; Études
Phycol., Pls. 32-35.—Pœcilothammion corymbosum, Næg.)
Fronds tufted, two to three inches high; filaments very delicate, cortications
wanting except at base, main branches several times pinnately or irregularly
divided, secondary branches pinnate with dichotomously-multifid, fastigiate
branches which end in hyaline hairs; tetraspores tripartite sessile at the nodes of the
branchlets, occupying the place of an ultimate branchlet; antheridia in tufts, sessile
on the upper internodes; favellæ binate on the upper part of the branches.
Var. SECUNDATUM, Harv.
Lesser branches frequently secund, ultimate branchlets irregular, scarcely
corymbose.
On Zostera.
Halifax, Boston Bay, New London, Providence, Harvey. The var. secundatum,
Massachusetts Bay, Greenport, Harvey.