Vol.. 1] Sefchell-Gardner. — Alga' of Northwestern America. 183 



Oscillatoria limosa Agardh. 



Floatiug on ditches of slightly brackish water. La Conner, 

 Skagit Connty, Wash., N.L.G., Nos. 333!, 334!; Whidbey 

 Island, Wash., N.L.G. , No. 615! 



The determinations given above are not absolntely satisfactory 

 to ns. 



Oscillatoria Bonnemaisonii Cronan. 



In salt . marshes . Whidbey Island, Wash ., N.L.G.. No . 2.')2 ! 



The filaments measnre only 12-15 /* which is small for this 

 species. Otherwise, the characters are in agreement with the 

 description . 



Oscillatoria nigro-viridis Thwaites. 



In salt marshes. Whidbey Island, Wash., A". //.(?., No. 615! ; 

 Seattle, Wash., Professor R. R. Foster, No. 601? 



Oscillatoria tenuis var. tergestina (Kuetzing) Rabenhorst. 



In pools of fresh or slightly brackish water. Whidl)ey Island, 

 Wash., N.L.G., Nos. 470!, 596!; Seattle, Wash., N.L.G., 

 No. 396! 



Oscillatoria tenuis var. '! 



Floating in slightly brackish water in a ditch. La Conner, 

 Skagit Connty, Wash., N.L.G., No. 333! 



Agrees well with 0. ten ids, except that it is hardly at all 

 torulose. 



Oscillatoria amphibia Agardh. 



In mud at bottoms of ponds. Whidbey Island, Wash., 

 N.L.G., Nos. 460a!, 470! 



Oscillatoria geminata Meneghini. 



On mud by the roadside. La Conner, Skagit County, Wash., 

 N.L.G., No. 331! 



The determination is not absolutely certain. 



Oscillatoria chlorina Kuetzing. 



In mud at the bottoms of shallow . ponds of fresh water. 

 Whidbey Island, Wash., N.L.G., No. 460!, and in Collins, 

 Holden and Setchell, P.B.-A., No. 901! 



