1925] SeicJieU-Gardner: Melanophyceae 435 



tophores numerous, discoid ; zoosporangia on short stalks or inter- 

 calary, globose, about 30fi diam. ; gametangia cylindrical to ovoid, 

 obtuse or acuminate, lateral, borne on longer or shorter pedicels, 

 70-150;u, long, 25-50/A broad. 



Growing on Fucus, in the middle of the littoral belt. Pacific 

 Grove, California. 



Setchell and Gardner, Phyc. Cont. VI, 1922, p. 411. Ectocarpus 

 paradoxus var. pacificus Saunders, Phyc. Mem., 1898, p. 152, pi. 18, 

 figs. 4—7; Collins, Holden and Setchell, Phyc. Bor.-Amer. (Exsicc), 

 no. 530. 



According to Saunders, his plant, the var. pacificus, differs from 

 the type of E. paradoxus Mont., in lacking any manifestation of 

 opposite branching as well as in having the gametangia longer and 

 more pointed. In these respects and also because it is a shorter plant, 

 it seems to us to be sufficiently distinct to be separated specifically 

 from the type, and to be different from any other species known to us. 



27. Ectocarpus acuminatus Saunders 



Fronds diminutive, attached by a network of delicate rhizoidal 

 filaments ; erect filaments uniform in size throughout, 1-2 mm. long ; 

 cells cylindrical, not constricted, 12-14/a diam., quadrate below, 2-5 

 times as long above ; chromatophores irregular or elliptical disks, more 

 abundant in the central part of the filament than elsewhere ; zoo- 

 sporangia unknown ; gametangia sessile on the creeping filaments or 

 on the base of the erect filaments or terminal on short filaments arising 

 directlj' from the creeping filaments, very long-acuminate, sometimes 

 tipped with a short hair, often more or less curved, 90-300/^ long, 

 20-30/t broad. 



Growing within the conceptacles of Cystoseira osmundacea and 

 Halidrys dioica. Central California (Pacific Grove) to southern 

 California (San Pedro). 



Saunders, Phyc. Mem., 1898, p. 149, pi. 14, figs. 1-5; Collins, 

 Holden and Setchell, Phyc. Bor.-Amer. (Exsicc), nos. 524 and 2142. 



The shape of the gametangia would seem to ally this very incon- 

 spicuous species most closely with E. siliciUosus, but the chromato- 

 phores are described by Saunders as elliptical. We have only dried 

 material for examination and cannot, therefore, add anything to the 

 description by Saunders. It is a very curious and seemingly distinct 

 species. Its habitat, wathin the conceptacles of members of the 

 Fucaceae, seems to have reduced it almost to the state of parasitism, 

 at least one-half of the plant being unable to function in food making. 



