268 University of California Publications in Botany [Vol. 8 



7, Ulva expansa (Setchell) S. and G. 



Frond ample, pale green, orbicular or broadly elongated, margin 

 deeply ruffled; frond 60-70/a thick in the middle, 38-45ju on the 

 margins; cells, in section, vertically elongated in the middle of the 

 frond (up to 28-30ja long, 10-12ja wide), nearly square in the margins. 



Growing on rocks in the lower littoral belt. Washington (Puget 

 Sound) to Mexico (La Paz). 



Setchell and Gardner, Phyc. Cont. I, 1920, p. 284. Ulva fasciata 

 f. expansa Setchell, in Collins, Holden and Setchell, Phyc. Bor.-Amer. 

 (Exsicc), no. LXXVII; Collins, Green Alg. N. A., 1909, p. 216. 



We find along the coast of central California a broad species of 

 Ulva, often also long, something like Ulva latissima in appearance, yet 

 of a more vivid green color, thicker in the center of the frond and 

 with distinct, broad, ruffled margins. The cells of the thicker center 

 of the frond are distinctly palisade-like in section, while on the 

 thinner margins they are nearly square. A younger specimen of this 

 plant was distributed by one of us as Ulv€^ fasciata f. expmisa (Phyc. 

 Bor.-Amer., no. LXXVII), but it has seemed, on further study, to 

 belong neither to Ulva fasciata Delile nor to the Ulva fasciata f. 

 tacmata also distributed by one of us (Phyc. Bor.-Amer., no. 809), 

 but described later in this account as Ulva taeniata. We have there- 

 fore described it (Setchell and Gardner, 1920, p. 284) as an indepen- 

 dent species under the name of Ulva expansa. 



Ulva expansa, so far as we have observed it, remains attached only 

 for a short time. It soon becomes free and floats or drifts, increasing 

 in size, becoming at times at least 3 meters long and varying in width 

 from 18 cm. to 75 cm. In form and structure it differs from Ulva 

 latissima and from all the other species of Ulva of our coasts. It comes 

 nearest to Ulva fenestrata as we have described that species, but is 

 little, if at all, perforate. Plants of what appears to be the same 

 species have been found in the Puget Sound region and Howe (1911, 

 p. 490) is inclined to credit here some from La Paz, Mexico. 



8. Ulva lobata (Kuetz.) S. and G. 



Frond dark green, of moderate size (up to about 30 or more cm. 

 long and 10-15 cm, broad), more or less deeply lobed or divided, 

 attenuate to a cuneate, crisped, often more or less twisted base, 



