1919] Setchell-Gardner : Myxophyceae 65 



This species approaches 0. hrevis Kuetz. but is somewhat smaller, 

 with proportionally longer cells and a different arrangement of gran- 

 ules. It never has the occasional swollen cells so fairly characteristic 

 of 0. hrevis. It is present in seemingly typical form in salt marsh 

 pools about San Francisco Bay. The plant from Whidbey Island, 

 referred here with some doubt (cf. Setchell and Gardner, 1903, p. 184), 

 on further examination seems to be referable rather to 0. hrevis var. 

 neapolitaiia. 



D. Oscillatoria acuminata Gomont 

 Plate 1, fig. 11 



Trichomes entwined in a dense thin layer of a verdigris color, 

 delicate, straight, slightly constricted at the partitions, 3-6//, diam. ; 

 a few apical cells attenuated to a sharp point, not uncinate ; length 

 of cells 5-8/A ; protoplast finely granular, with the granules frequently 

 crowded at the dissepiments. 



Floating in warm salt water. Oakland, California. 



Gomont, Monogr. des Oscill., 1892, p. 227, pi. 7, fig. 12 (1893, 

 p. 247, Repr.) ; Collins, Holden and Setchell, Phj'c. Bor.-Amer. 

 (Exsicc), no. 1303. 



The type specimen of Oscillatoria acuminata was collected at the 

 Euganean springs, but has since been reported from other waters in 

 several widely separated localities. Our specimens from warm or 

 almost hot pools of brackish waters agree too nearly with the descrip- 

 tion and figures of Gomont to allow of separation. The plants dis- 

 tributed under no. 1303 of the Phycotheca Boreali-Americana, which 

 are from the vicinity of hot salt waters, have shorter cells than the 

 type. 



10. Oscillatoria brevis Kuetz. 



Filaments fonning dense olive green layers or intermixed with 

 other species of algae, of blue-green color, comparatively short and 

 straight, rather fragile, 4-6. S/x diam., not constricted at the dissepi- 

 ments, briefly and subacutely attenuate, uncinate or slightly twisted; 

 cells very short, 1.5-3/i, long, with an occasional refringent torulose 

 cell interspersed; protoplasm with small granules evenly dispersed 

 throughout the cell. 



Growing among other algae in salt mai*sh pools. San Francisco 

 Bay, California. 



