432 University of California Publications in Botany [Vol. 8 



23. Ectocarpus affinis S. and G. 



Plate 51, figs. 16, 17 



Fronds diminutive, 500-700/4 high, attached to the host by a few 

 branched, colorless, entwining, rhizoidal filaments; erect filaments 

 sparingly branched, gradually attenuated upward, piliferous; branches 

 alternate or opposite ; cells of the main filaments cylindrical, 24-30**. 

 diam. at the base, 9-11/*, at the apex, varying in length throughout the 

 filament, 0.75-3 times as long as the diameter; chromatophores small, 

 thin, angular plates in young cells, nearly regular disks in older cells ; 

 zoosporangia unknown ; gametangia lateral, mostly sessile, occasionally 

 on 1-celled pedicels, solitary, secund, or in whorls from a single cell. 

 blunt-conical to spheroidal, 28-31/*. long, 25-28/* broad, arranged 

 along the entire filament to the terminal hairs. 



Growing on CaUithamnion sp. Sitka, Alaska. 



Setchell and Gardner, Phyc. Cont. VI, 1922, p. 405, pi. 46. figs. 

 16, 17. 



Two collections from Sitka, Alaska, but both made on the same 

 day, show a small Ectocarpus growing on a species of CaUithamnion 

 which is so closely related to E. ovattis Kjellman (1877a, p. 35) that 

 perhaps it may seem necessary, at some time, to refer it to that 

 species. The plants are, however, less stout than those of Kjellman and 

 with more nearly spherical gametangia. For these reasons and because 

 of its geographic remoteness and the somewhat different climatic con- 

 ditions, we feel that it is desirable to describe the Alaskan plant as a 

 distinct, but closely related, species. 



24. Ectocarpus cylindricus Saunders 



Fronds diffuse, 1-2 mm. high ; creeping filaments superficial ; erect 

 filaments very sparingly branched above, several arising from the 

 same creeping filament, tapering slightly at the base and apex; cells 

 of the creeping filaments 16-20/x diam.; cells of the erect filaments 

 cylindrical, slightly constricted at the cross-walls, 2-3 times as long as 

 broad below and at the apex, 0.5-1 times in the middle of the filament ; 

 gametangia mostly on the middle and upper parts of the filaments, 

 usually alternate. 



Growing on Egregia Menziesii and Cystoseira osmundacea. Central 

 California (Pacific Grove). 



