Vol. 1] ^eicheU-Gardner. — Alga' of Xorfjitrpsfev)! America. ^41 



439, under Pfilota plMmosa); Vancouver Island, B. C, J. G. 

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

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

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

 Wash., K.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, 

 but 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 PfUoia pJuiiiosd really ])elong to this species, 

 since we have been unal)le to find any of the former among 

 the specimens we have been able to examine. 



Ptilota pectinata (Gunner) Kjellman. 



On rocks in the lower litorai and upper sublitoral zones. 

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

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

 Nos. 58041)!, 5809!; Agattu Island, Alaska, Toirnsend, No. 

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

 Ptilota serrata)- San Juan Island, Wash., X.L.G., No. 218! 



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

 tain of, the opposite pinnules are dififerent, one being pinnately 

 branched while the other remains simple and only serrate. 



Antithamnion floccosum f. Pacificum (Harvey) Setchell 

 and Gardner com)), nov. 



Most commonly on the stipes of Nereocystis, sometimes on 

 other algff" and on wood, in the upper sublitoral zone. Yakutat 

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

 (1901, p. 439, under CallitJiannrion ftorrosinn Pacificinn) ; Esqui- 

 malt, B. C, Harvey (1862, p. 176, under Callithanniion floccosum 

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

 and PolU'ii^ Xo. 21!; west coast of Whidbey Island, Wash., 

 X.L.G., No. 620!; Orcas Island, Wash., liarreg (1862, p. 176. 

 under Gallitlaintnion floccosum var. I'aciflcun/) ; Friday Harbor, 

 San Juan Island, Wash., Tihlen, No. 309!. under CallifJiau/nion 

 BoT.— 2:i 



