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- 



