1920] Setcheil-Gardner : Chlorophyce<ae 225 



those of S. arcta (up to 200/t or over at the tips), but we have seen 

 none approximating the maximum diameter (500/* at the tips) given 

 for the Atlantic-Arctic plants. The Tilden specimens (American 

 Algae, no. 374), issued as Cladophora arcta form b, and assigned to 

 C. Hystrix bj' Setchell and Gardner (1903, p. 226), prove on exam- 

 ination to have compound hooked branchlets and have been assigned, 

 consequently, to Spongomorpha coalita in this account. Specimens 

 from Karluk and from Uyak Bay, Alaska, assigned by Setchell and 

 Gardner to Cladophora arcta and its form conglutinata are now 

 referred here, after careful examination. The status of this species 

 on our coast, however, is subject to careful revision as soon as more 

 abundant material for study and comparison is available. 



Spongomorpha Hystrix might be compared with S. durkiscula, 

 so far as description goes, but the species are very different in aspect, 

 the former being closely matted together below, while the latter shows 

 so loose an intermingling of the filaments as to suggest the possibility 

 of its belonging rather to Cladophora than to Spongomorpha. The 

 segments also in iS^. durkiscula are usually shorter and those of the 

 main filaments are horizontall}' striate. 



3. Spongomorpha duriuscula (Rupr.) Collins 



Tufts 15-25 cm. high, erect, loose, main filaments firm, straight, 

 with thick, horizontally striate walls, 200-250/* diam. below, 300/* at 

 the tip; segments 0.5-1.5 diam. long, 2-3 diam. at the blunt tips; 

 branches similar, erect, scattered or in secund series of two or more ; 

 near the base of the tuft more slender, 150-200/x diam., with thinner 

 walls, not striate, with numerous short, patent ramuli, scattered or 



secund. 



Growing on rocks in the upper sublittoral and lower littoral belts. 



Alaska (Pribilof Islands to Karluk). 



Collins, Green Alg. N. A., 1909, p. 357. Cladophora alaskan^ 

 Collins, in Collins, Holden and Setchell, Phyc. Bor.-Amer. (Exsicc), 

 no. 917 (nomen nudum), in Setchell and Gardner, Alg. N.W. Amer., 

 1903, p. 228 (description). Conferva durkiscula Ruprecht, Tange, 

 1851, pp. 401-404. Conferva oartilaginea Ruprecht, Tange, 1851, 

 p. 404 (fide Yendo). Acrosiphonia duriuscula Yendo, Notes on algae 

 new to Japan, V, 1916, p. 246. 



The type locality of Conferva duriuscula Ruprecht is Unalaska, 

 where it was collected by Wosnessenski (no. 108) as the type specimen 



