vol.i] Setchell-Gardner. — Algce of Northwestern America. 329 



Pterosiphonia Woodii (Harvey) Falkenberg. 



Ou the stipes of Pleirrophycus and other kelps in the upper 

 sublitoral zone. Port Renfrew, B. C-, Butler and Policy, No. 

 1! : west coast of Whidbey Island, Wash., N.L.G., Nos. 12!, 38! 



More or less common on the shores of California. 



Pterosiphonia arctica (J. Agardh) Setchell and Gardner comb, 

 now Plate 19. 



On large alga? in the upper sublitoral zoue or floating. Near 

 Iliuliuk. Unalaska, Alaska, W.A.8. and A.A.L., No. 5002!; 

 Shumagin Islands, Alaska, Saunders (1901, p. 438, under Poly- 

 siphonia arctica) : west coast of Whidbey Island, Wash., X.L.G., 

 Nos. 59!, 226!, 227!, 413!, .511! 



We are uncertain as to the type of Polysiphonia arctica J. 

 Agardh, but we have been able to compare ours with a specimen 

 from Rosenvinge, through the kindness of F. S. Collins. This 

 specimen was old and battered and there was difficulty in obtain- 

 ing good tips. Ours seemed to be very close to it and conse- 

 quently we have placed it under this name. Our plants vary 

 much in coarseness, are plainly distichous near the tips, have con- 

 stantly six or seven pericentral cells, and have the tips mucronate 

 aud devoid of hairs. Our figures show the Alaskan specimens 

 which are coarser than those from Puget Sound. We have not 

 seen the plant of Saunders. Our plants are certainly good 

 species of Pterosiphonia as Falkenberg has described the genus. 



Lophosiphonia obscura (Agardh) Falkenberg. 



On sand covered rocks in the literal zone. San Juan 

 Island, Wash., Tilden, No. 317, under Polysiphonia In pim t afa - f. 

 psammicola. *U*-hMi*AU^ 



This species is quite common on the coast of California. It 

 answers well to the descriptions of this species and has been corn- 

 pared with European specimens by F. S. Collins. 



Lophosiphonia villum (J. Agardh) Setchell and Gardner comb. 

 nov. 



On Fucus, lower literal zone. St. Paul, Kadiak Island, 

 Alaska, W.A.H. and A.A.L., No. 5138! 



