224 University of California Piiblioations in Botany [Vol. 8 



theca Boreali-Americana referred to f. pulvinata. This plant also is 

 referred by us to S. spinescen^. While specimens of what we retain 

 under S. arcta have also been referred to these varieties, they differ 

 in habit from that described for either variety and we consequently 

 refer them to S. arcta without attempting any varietal distinction. 



It has been customary to refer under Spmigomorpha arcta, at least 

 in the broader sense in which we are, at present, compelled to use 

 the name. Conferva cohaerens of Ruprecht (1851, p. 402). Ruprecht, 

 himself, says that it is probably only a subspecies of C. arcta. The 

 type specimens of C. cohaerens came from the North Pacific Ocean, 

 probably from ' ' Awatschabai ' ' in the Sea of Ochotsk. Ruprecht states 

 that his Conferva cohaerens is to be only slightly distinguished from 

 the British C. arcta (of Mrs. Griffiths) by having the thicker varie- 

 gated lateral branchlets which are abruptly attenuated to a point 

 of %oo line (about 11. 3/^) in diameter (main filaments 75-80ja). 

 C. cohaerens also differs particularly from C. saxatilis Rupr. in its 

 intertwined filaments and its lower, more slender and shorter branch- 

 lets. The type specimen of C. cohaerens in the Herbarium of the 

 Imperial Academy of St. Petersburg has the appearance and habit 

 of Spongomorpha arcta, but it is very desirable that it be carefully 

 examined microscopically before being finally referred, 



2. Spong-omorpha Hystrix Stroemf. 



Plants rich green, in rather dense tufts, filaments straight, very 

 erect, except those at the base of the tuft, which are somewhat more 

 open; about 100-300/x, diam. at the base, 200-500/i, diam. at the tip 

 ultimate segments blunt or clavate, not attenuate ; segments up to 4 

 diam. long at the tip, 0.5-1.5 diam. long below; rhizoidal branches 

 fairly common in the older parts, 40-70/x diam., segments 3-10 diam. 

 long. 



Forming a dense mass on rocks in the littoral belt. From Agattu 

 Island to Sitka, Alaska. 



Stroemfelt, Om Algvegt. vid Island Kuster, 1887, p. 54; Collins, 

 Green Alg. N. A., 1909, p. 358 ; not Setchell and Gardner, Alg. N.W. 

 Amer., 1903, p. 226. 



Spongomorpha Hystrix seems to be a high northern species of the 

 arcta group, differing primarily from 8 pong on/nor pha arcta in the 

 greater diameter of the filaments. The specimens referred by us in 

 our final disposition of the species, have much larger filaments than 



