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1925] Setchell-Gardner: Melanophyceae 413
by never having the gametangium prolonged into a hair, from E.
ac at us by having blunt or piliferous branches, and from all the species
of Ectocarpus having band-shaped chromatophores by the shape and
dimensions of its gametangia.
Key to the Forms
1. Gametangia seldom over 100^ long 2
1. Gametangia usually over 100/u long, even up to 400m long f. parvus (p. 413)
2. Fronds frequently branched above, branches long... f. typicus (p. 414)
2. Fronds sparsely branched above, branches short 3
3. Gametangia frequent above, seldom terminal f. variabilis (p. 414)
3. Gametangia occasional above, frequently terminal f. pygmaeus (p. 415)
Ectocarpus confervoides f. parvus (Saunders) S. and G.
Fronds gregarious, forming tufted or extended masses, 1-2 cm.
high, more or less alternately branched ; erect filaments 21-30/x broad,
slightly constricted at the joints, much attenuated at the tips or end-
ing in hairs ; cells 1—3 times as long as broad below, shorter above
chromatophores irregularly band-shaped ; zoosporangia ovoid or ellips-
oid, 35-55/a long, 20-27/a broad, usually sessile, sometimes on the same
filament with the gametangia; gametangia narowly lanceolate-conical,
gradually long-attenuate above, 120-400/i. long, 20-27^ broad, borne
on a longer or shorter pedicel, occasionally seriate and intercalary
(as in PylaieUa).
On sand-covered rocks (type!), logs, or on the larger Melano-
phyceae. Central California (near San Francisco) and southern
California (San Pedro and the type locality, San Diego).
Setchell and Gardner, Phyc. Cont. VI. 1922, p. 414. Ectocarpus
siliculosus parvus Saunders, Phyc. Mem. 1898, p. 153, pi. 22, figs. 1-9.
The f. parvus, as defined above, presents certain resemblances to
both Ectocarpus siliculosus and E. confervoides. Its slender elongated
gametangia resemble those of E. siliculosus and much might be said
in favor of the opinion of Saunders in making it a "variety" of that
species. On the other hand, very few, or none, of the typical game-
tangia end in a hair and we have therefore preferred rather to place
it with E. confervoides. There are often found in this form, as well
as in forms of E. siliculosus, very curious elongated intercalary game-
tangia which seem to be seriate, in that they open laterally in sections,
as do those of PylaieUa. Such gametangia are very puzzling, but
may possibly be regarded as indicating hybridization between Pylai-
eUa and Ectocarpus or a mutation of some sort. Speculation, how-
ever, can scarcely explain such anomalies. The majority of the game-
;