226 University of California Publications in Botany [Vol. 8 



shows. The type specimen is of exactly the same habit and appearance 

 as the specimens distributed under no. 917 of Collins, Holden and 

 Setchell's Phycotheca Boreali-Americana, which are topotypes, prob- 

 ably collected at the very same spot whence Wosnessenski obtained 

 the type. 



Spongomorpha durinscula is a coarse, lax species whose filaments 

 are so slightly bound together that the plant seems much less like a 

 Spongomorpha than either of the preceding species. There are some 

 slender rhizoidal branches, however, and the main filaments increase 

 in diameter towards their summits. The walls of the segments of 

 the main filaments and longer branches are thick and horizonally 

 striate as Ruprecht has stated. It seems to be a very distinct species 

 of the Upper Boreal Zone. 



Yendo (1916, p. 246) has placed this species under Acrosiphonia 

 and, after examining the types, has united with it Conferva cartila- 

 ginea Ruprecht (1851, p. 404) whose type locality is also Unalaska. 

 He also refers here Tilden's no. 373 (Amer. Alg.) under Cladophora 

 arcta. The two ("a" and "b") specimens in our copy are, however, 

 clearly Spongomorpha coalita, both as to habit and as to the possession 

 of compound hooked branchlets. Yendo states that Kjellman (1889, 

 p. 55) included plants of this species under his Cladophora difusa 

 from Bering Island, Siberia. 



4. Spongomorpha saxatilis (Rupr.) Collins 



Plants dense but not much matted together; filaments 80-120jtt 

 diam., about the same diameter throughout, segments below 1-3 diam. 

 long, above 3-6 diam., terminal segments sometimes 10-12 diam. ; 

 branching di- trichotomous, with occasional lateral branches, divisions 

 erect, somewhat acute or tapering, but usually with rounded tip ; older 

 parts with descending rhizoidal filaments, about half the diameter of 

 the filaments from which they spring, and with longer segments some- 

 times 10-12 diam. long. 



On rocks in the lower littoral belt. Alaska to San Francisco, Cali- 

 fornia. 



Collins, Green Alg. N. A., 1909, p. 360, Mar. Alg. Vancouver 

 Island, 1913, p. 104. Conferva saxatilis Ruprecht, Tange, 1851, p. 403. 

 Cladophora saxatilis (Rupr.) De-Toni, Syll. Alg., vol. 1, sect. I, 1889, 

 p. 311 ; Setchell and Gardner, Alg. N.W. Amer., 1903, p. 223 ; Collins, 

 Holden and Setchell, Phyc. Bor.-Amer. (Exsicc), no. 921. Clado- 

 phora arcta Tilden, Amer. Alg. (Exsicc), no. 279 (not of Kuetzing). 



