v.»i.. i] SetcJiell-Gardner. — Algce of Northwestern America. 341 



439. under Ptilota plumosa); Vancouver Island, B. C, J. G. 

 Agardh (1876. p. 76); Port Renfrew, B. C, Butler and Polley, 

 No. 91; Brown Island, San Juan County, Wash., Tilden, No. 

 306!. under Ptilota plumosa; west coast of Whidbey Island, 

 Wash., X.L.G., No. 1! 



When typical, this species is not difficult to determine by the 

 fact that the opposite pinnules may differ in size and development, 

 bxit not otherwise, and are corticated to the very tip. In prac- 

 tice, however, it is, at times, somewhat uncertain as to whether 

 a given specimen belongs to this species or to the next. We 

 have taken it somewhat for granted that the plants from our ter- 

 ritory referred to Ptilota plumosa really belong to this species, 

 siuee we have beeu unable to find any of the former among 

 the specimens we have been able to examine. 



Ptilota pectinata (Gunner) Kjellman. 



On rocks in the lower literal and upper sublitoral zones. 

 St. Lawrence Island. Alaska. Kjellman (1889, p. 32); St. Paul 

 Island. Alaska, Toirnsend, No. 5783!, Greeley and Snodgrass, 

 Nos. 5804b!, 5809!; Agattu Island, Alaska, Toionsend, No. 

 5765! ; Shumagin Islands, Alaska, Saunders (1901, p. 439, under 

 Ptilota serrata) ; San Juan Island, Wash., N.L.G., No. 218! 



In this species, which is, at times, very difficult to make cer- 

 tain of. the opposite pinnules are different, one being pinnately 

 branched while the other remains simple and only serrate. 



Antith amnion floccosum f. Pacificum (Harvey) Setchell 



and C4ardner comb. uov. 



Most commonly on the stipes of Nereocystis, sometimes on 

 other alga? and on wood, in the upper sublitoral zone. Yakutat 

 Bay and Lowe Inlet, Alaska, and in Puget Sound, Saunders 

 (1901. p. 439. under Callitliamnion floccosum Pacificum); Esqui- 

 nialt. B. C Harvey (1862, p. 176, under Callitliamnion floccosum 

 var. Pacificum), X.L.G., No. 325!; Port Renfrew, B.C., Butler 

 ami Polley, No. 21!; west coast of Whidbey Island, Wash., 

 N.L.G., No. 620!: Orcas Island, Wash., Harvey (1862, p. 176, 

 under Callitliamnion floccosum var. Pacificum); Friday Harbor, 

 San Juan Island, Wash., Tilden, No. 309!, under Callitliamnion 



Bot.— 23 



