270 University of California Publications in Botany [Vol. 8 



Agardh, Sp., vol. 1, part 2, 1822, p. 410. Ulva Luctuea var. rigida 

 Le Jolis, Alg. Mar. Cherb., 1863, p. 38; Collins, Green Alg. N. A., 

 1909, p. 215 (in part). Mar. Alg. Vancouver Is., 1913, p. 103 (in 

 part) ; Saunders, Alg. Harriman Exp., 1901, p. 410 (in part) ; 

 Setchell and Gardner, Alg. N.W. Amer., 1903, p. 209 (in part) ; Howe, 

 Phyc. Studies, V, 1911, p. 490. 



Viva rigida must needs be carefully studied and redescribed from 

 the type specimen before any exact knowledge is possible as to the 

 nature of the species. Agardh (1822, p. 410) describes it as from 

 3 or 4 up to about 9 inches long, split to the base into curved and crisp 

 laciniae. J. G. Agardh (1883, p. 168) describes it as having cells 

 vertically elongated in section to 2 to 3 times their width. He, how- 

 ever, refers as tj'^pical the figure of Viva Lactuca of Thuret and Bor- 

 net's Etudes Phycologiques (1878, pi. 2, e). Yendo (1916, p. 244) 

 says that J. G. Agardli has taken a broader view of the species than 

 did C. Agardh. Yendo refers to V. rigida, in the sense of its founder, 

 the Viva conglohata Kjellm. and its f. densa as well as the Viva fasci- 

 ata f. caespito'sa Setchell (Phyc. Bor.-Amer., no. 809). Yendo does 

 not, however, state definitely just the characters of the type of V. 

 rigida Ag. 



The Viva conglohata Kjellm. seems to us to agree well with the 

 V. fasciata f. caespitosa Setchell (Phyc. Bor.-Amer., no. 809, nom. 

 nud. ) , both as to habit and as to structure. The cells in each are only 

 slightly, if at all, elongated vertically in section. We are inclined to 

 refer both of these plants to Viva Lactuca as small forms. The Viva 

 conglohata f. densa, however, seems different in its structure. Judg- 

 ing by Kjellman's figure (1897a, pi. 3, f. 15), the cells are decideflly 

 vertically elongated in cross section, and this form probably, therefore, 

 belongs to V. rigida in. the sense of J. G. Agardli. 



We have, in the light of what has been written, considered the 

 Viva rigid^i to be a low plant, rigid, deeply divided, rather thick and 

 with cells vertically elongated in section. The membrane usually 

 shows a rather thick hyaline layer under each surface, and another 

 between the layers of cells. We have found that certain of our speci- 

 mens conform to these characters and are to be distinguished by them 

 from any other species of Viva. 



