1920] Setchell-Gardner : Chlorophyceae 217 



five forms of this species as abounding on the Atlantic coast of North 

 America. 



We are placing under C. gracilis two sets of plants differing con- 

 siderably from one another, mainly in details of measurements, as 

 apparently closely allied to the Atlantic coast forms, but they do not 

 seem to be identical with any of them. No. 3954 Gardner, from Sitka, 

 Alaska, has the main filaments up to lOO/t in diameter. No. 3870a 

 Gardner, from Neah Bay, "Washington, has slightly smaller dimensions 

 than no. 3954. The ultimate ramuli in both of the above mentioned 

 collections, while being more or less secund, are not so much so as is 

 usually recorded for the species. No. 3870a is fruiting abundantly 

 at the tips of the ramuli, the segments becoming decidedly ventricose 

 or even spherical in reproduction. These two collections are placed 

 here provisionall}' awaiting further investigation into the status of 

 the species. 



n. Cladophora flexuosa (Griff.) Harv. 



Plants 10-20 cm. high, light green ; main filaments 80-120jU, diam., 

 regularly flexuous, with flexuous alternate branches, 40-80;ti diam., 

 which in turn have alternate or secund, curved and sometimes 

 refracted ramuli ; segments from 6 diam. long below to 2 in the ramuli. 



Growing in rock pools in the lower littoral belt. Annettee Island, 

 Alaska, to San Diego, California. 



Harvey, Phyc. Brit., 1851, p. 353 ; Collins, Green Alg. N. A., 1909, 

 p. 339; Setchell and Gardner, Alg. N.W. Amer., 1903, p. 224; Col- 

 lins, Holden and Setchell, Phyc. Bor.-Amer. (Exsicc), no. 2239. 

 Conferva flexuosa Griffiths, in Wyatt, Alg. Danm., no. 227. 



The status of the name Cladophora flexuosa is equivocal. The 

 plant usually referred here does not seem to be at all certainly the 

 Conferva flexuosa Dillwyn (1802, pi. 10) nor that of Mueller in the 

 Flora Danica (1782, p. 5, pi. 882), but more probably that of Mrs. 

 Griffiths {in Wyatt 's, Alg. Danm., no. 227), later adopted by Harvey 

 (1851, pi. 353) and referred to Cladophora. Our west coast plants 

 have been referred here chiefly on the authority of Collins. 



12. Cladophora Rudolphiana (Ag.) Kuetz. 



Plants loose, soft, yellowish green, gelatinous, up to a meter in 

 length ; main filaments 40-80/^ diam. ; branches alternate or opposite, 

 patent, flexuous, ramuli secund, tapering, about 20/i, diam.; segments 

 much longer than broad, up to 20 diam. below. 



