vol.1] SetcheU-Gardner. — Algm of Northwestern America. 185 



The filaments of the Phormidium are rather slender, measuring 

 1.5-1.8 /* in diameter. 



Phormidium laminosum (Agardh) Gomont. 



On dripping rocks or in spring water. Orea, Alaska, Saunders 

 (1901, p. 398); San Juan Island, Wash., N.L.G., No. 485! 



Phormidium tenue (Meneghini) Gomont. 



In various situations, submerged and emergent, iu fresh 

 water. Walls of Amaknak Cave, Amaknak Island, Bay of 

 Unalaska, Alaska, W.A.8. and A.A.L., No. 3292!; Coupeville, 

 Wkidbey Island, Wash., N.L.G., No. 450!; Oak Harbor, 

 Whidbey Island. Wash., X.L.G., No. 574!; Seattle, Wash., 

 X.L.G.. Nos. 593!, 597! 



No. 3292 shows the form with the uncinate tip almost entirely. 



Phormidium inundatum Kuetzing. 



On a chipping water pipe or in watering troughs. Victoria, 

 B. C, W.L.G., No. 319! ; Seattle, Wash., N.L.G., No. 393! 



Phormidium Corium (Agardh) Gomont. 



Mixed with other alga?, particularly of the same family, either 

 submerged or exposed to the air. Cape Nome, Alaska, W.A.8. ! ; 

 Glacier Valley, Unalaska, Alaska, A.A.L., No. 5029c!; near 

 Iliuliuk, Unalaska, Alaska, IF.A.&. and A.A.L., No. 5045x! 



The specimens referred here are not altogether typical, but 

 seem to belong to this species rather than to any other described. 



Phormidium papyraceum (Agardh) Gomont. 



At the outlet of a lake. Orcas Island, Wash., N.L.G., 

 No. 613! 



Phormidium Retzii (Agardh) Gomont. 



Growing on a submerged log. Green Lake, Seattle, Wash., 

 N.L.G., No. 369! 



Mixed with the following. 



Phormidium ambiguum Gomont. 



Growing on a submerged log. Green Lake, Seattle, Wash., 

 N.L.G., No. 369! 



Mixed with the preceding. 



