62 I'liinrsity of California Fuhlications in Botany [Vol.8 



■4. Oscillatoria nigro-viridis Thwaites 



Plants forming extensive dark olive green layers; trichomes olive 

 green, of moderate length, nearly straight, fragile, torulose, T-ll/x 

 diani., sliglitly curved at the extremities; apex slightly tapering; end 

 cell wall very convex, sliglitly thickened; cells 3-5/* long, witli two 

 rows of granules at the cross walls. 



Growing in pools in salt marsh, Whidbey Island, Washington, 

 and on the shores of San Francisco Bay, California. 



Thwaites, in Harvey, Phyc. Brit., Synopsis, vol. 3, 1849, p. xxxix, 

 no. 375, pi. 251, fig. A ; Gomont, Monogr. des Oscill., 1892, p. 217, pi. 6, 

 fig. 20 (1893, p. 237, Kepr.) ; Setchell and Gardner, Alg. N.W. Amer., 

 1903, p. 183. 



This is another more or less puzzling species of the "Margariti- 

 ferae" section, but certain specimens both from Puget Sound and 

 from the San Francisco Bay region seem referable to it. There is 

 some departure from the descriptions in some specimens. In filaments 

 whose cells are actively dividing, the length of the cells may be as 

 short as one-sixth as long as broad, but are mostly one-third the 

 diameter. The filaments are mostly short arcuate in the California 

 specimens, and while some filaments show distinctly the transverse 

 rows of granules at the dissepiments, others seem nearlj^, if not quite, 

 to lack them. 



5. Oscillatoria Corallinae (Kuetz.) Gomont 



Trichomes aggregated into a thin, dark, olive green stratum or 

 intermixed with other small algae, aeruginous, densely intertwined, 

 flexuous, torulose, 6-10/a diam., apices long and moderately arcuate, 

 very slightly attenuate ; cells 2-3 times shorter than the diameter, 

 protoplast sometimes with sparsely scattered granules, not crowded 

 at the cross walls; apical cell subcapitate, with slightly thickened 

 convex terminal wall. 



Forming a thin stratum on rocks and on or among other small 

 algae. Lands End, San Francisco, California, Gardner, no. 1634; 

 Moss Beach, San Mateo County, California, Gardner, no. 2978 ; Pacific 

 Grove, Monterey County, California, Setchell, no. 5490&. 



Gomont, Essai Class Nost., 1890, p. 356 (in part), Monogr. des 

 Oscill, 1892, p. 218, pi. 6, fig. 21 ( 1893, p. 238, Kepr.). Leibleinia 

 Corallinae Kuetz., Sp. Alg., 1849a, p. 276. 



