434 University of California Publications in Botany [Vol.8 



25. Ectocarpus hemisphericus Saunders 



Fronds pulvinate, 2-4 mm. high, arising from a compact network 

 of creeping filaments rhizoidal in character, much attenuated and 

 crisped ; primary branches pseudodichotomous, divaricate, gradually 

 attenuated upward ; secondary branches numerous, short, clustered, 

 mostly long-piliferous; cells at the base of main filaments 22-26//. 

 diam., 1—3 times as long as the diameter, smaller above, slightly con- 

 stricted at the joints ; chromatophores numerous, small, discoid ; zoo- 

 sporangia cylindrical, 30-35/*. long, 20-25// diam., on 1-celled stalks, at 

 times on the same fronds with the gametangia (Saunders) ; game- 

 tangia fusiform to broadly ovoid, obtuse, 30-90//. long, 14-20// diam., 

 lateral on the upper parts of the fronds, short-pedicellate. 



Growing mostly on Pelvetia fastigiata, but also on other species of 

 algae. California (San Diego, Laguna and San Pedro). 



Saunders, Phyc. Mem., 1898, p. 151, pi. 17 ; Guernsey, Notes on 

 Mar. Alg., 1912, p. 198, fig. 108 ; Collins, Holden and Setchell, Phyc. 

 Bor.-Amer. (Exsicc), no. 528. 



Ectocarpus hemisphericus f. minor Saunders 



Very similar to the species, but forming less definite tufts and 

 with the erect filaments simple or but slightly branched, 1-2 mm. high, 

 16-21// diam., and with gametangia and zoosporangia mostly sessile. 



Growing on and near the receptacles of Hesperophycus Har- 

 veyanus. San Pedro, California. 



Saunders, Phyc. Mem., 1898, p. 151, pi. 18, figs. 1-3; Collins, 

 Holden and Setchell, Phyc. Bor.-Amer. (Exsicc), nos. 529 and 1794. 



Ectocarpus hemisphericus Saunders, in typical form, can readily 

 be recognized by its habit and its host, but in some forms and par- 

 ticularly in f. minor is less distinct in habit, at least. Thus far, both 

 the species and the form seem confined to the coast of southern 

 California. 



26. Ectocarpus Saundersii S. and G. 



Fronds forming small tufts, 2-5 mm. high, attached by a mass of 

 branched filaments creeping on the surface of the host ; branching 

 alternate ; main branches long and divergent, ultimate ramuli sparse, 

 short, acuminate; cells of the main filaments 25-40// diam., quadrate 

 below, shorter above, slightly constricted at the dissepiments ; chroma- 



