vol.i] SetcJiell-Gardner. — Algce of Northwestern America. 267 



a species of the very cold and rough waters. On the Island of 

 Amaknak, it grows in great abundance and was found in all 

 stages of growth. The earliest fronds are ovate and with short 

 stipes. Later they become broadly reniform and begin to roll 

 in at the edges on both sides of the stipe, looking very much like 

 a young Agarum Turneri in this stage. The scrolls thus formed 

 become more pronounced, perforations appear, and the central 

 portion of the frond begins to erode and wear away, until finally 

 there are left the much enlarged and thickened, perforated 

 scrolls which wear away on one edge (the inner) and continue to 

 unroll on the other. As they continue to grow, the basal portion 

 of each scroll becomes a sort of stipe and the young plant is 

 plainly dichotomous. As the plant grows on and branches in the 

 irregular manner described by Rosenthal (1890, p. 140, f . 33, 3-4) , 

 this basal dichotomy becomes inconspicuous, and does not seem 

 to have attracted attention before. Its peculiar origin is similar 

 to the process which takes place in Eisenia and in Hedophyllum 

 subsessile as mentioned above. 



Arthrothamnus bifidus (Gmelin) Ruprecht. 



Aleutian Islands, Alaska, Areschoug (1884, p. 14). 



We know nothing of the occurrence of this species of the 

 Ochotsk Sea and of Bering Island within our territory, farther 

 than the reference quoted above. 



Dictyoneuron Californicum Ruprecht. 



Port Renfrew, B. C, Tilden, No. 519! 



Apparently only just reaching the coast of Vancouver Island, 

 certainly not abundant in Pnget Sound. This is one of the com- 

 mon species at various localities on the central Californian coast. 



Lessonia litoralis Farlow and Setchell. 



Port Renfrew, B. C, Tilden, No. 342!, Butler and Polley, 

 No. 50. 



This species was first found on the coast of Oregon by E. 

 Hall, mentioned by Farlow (1875, p. 355), and doubtfully 

 referred to L. fuscescens. Later, the same author referred it to 

 L. nigrescens (1S76, p. 708), but on collecting good material at 

 Monterey, California, he recognized it as new, but only gave it 



