1920] Seichell-Gardner : Chlorophyceae 273 



Delile, so far as descriptions and figures indicate, in branching, in 

 ruffling, and probably in thickness. It is a very much thinner plant 

 than U. nematoidea Bory, judging from the dimensions given by 

 Bornet (1892, p. 36 or 196). 



13. Ulva t/eniata (Setchell) S. and G. 



'^ Plate 23 



Frond elongated, up to 1 or 2 M. long, simple or split to the very 

 base into long, narrow segments, plane below and coarsely dentate, 

 densely crisped and iniffled on the margins above, with a plane, thicker 

 midrib; membrane up to 140jtt thick as to the "midrib" and down 

 to 40/i, thick on the margins ; cells of the ' ' midrib ' ' vertically elongated 

 in section up to two and one half times as high as broad, but becoming 

 nearly square towards the margins. 



On rocks in lowermost littoral or upper sublittoral belts. Central 

 California (Tomales Bay to Monterey). 



Setchell and Gardjier, Phyc. Cont. I, 1920, p. 286, pi. 28. Ulva 

 fasciata f. taeniata Setchell, in Collins, Holden and Setchell, Phyc. 

 Bor.-Amer. (Exsicc), no. 862; Collins, Green Alg. N. A., 1909, p. 216. 



Viva taeniata has been found thus far on the coasts of central 

 California only, while Z7. dactylifera has been found only on those 

 of southern California. The differences between the two species have 

 been enumerated under the latter species. From U. fasciata f . costata 

 Howe, it differs particularly in its basal portion. Ulva fasciata Delile 

 seems to be a species nearly if not absolutely plane, while U. taeniata 

 is always crisply ruffled. No. 862 of the Phycotheca Boreali-Americana 

 represents this species very well. 



21. Percursaria Bory 



Frond slender, filamentous at first, of a single series of cells, later 

 becoming two longitudinal rows of cells placed symmetrically side 

 by side throughout, or only in portions, of the filament; cells 

 rectangular, with thick walls and a single chromatophore. 



Bory, Diet, class, d'hist. nat., vol. 13, 1828a, p. 206. Tetranema 

 Areschoug, Phyc. Scand. Mar., Sect. II, 1850, p. 418 (not Tetranema 

 Bentham, 1843). Diplmiema Kjellman, Norra Ishaf. Algfl., 1885a, 

 p. 371 (not Diplanevia Don, 1838, nor Diplanema De Notaris, 1846). 



