200 University of California Publications. [botany 



Althongh acknowledgment has been made of the very great 

 assistance given us by Mr. F. S. Collins, yet it should be empha- 

 sized again that he has made the determinations in the genera 

 Chsetomorpha, Cladophora, Enteromorpha, Monostroma, and 

 Urospora, and also scattering determinations in some other 

 genera. He has, beside this, kindly looked over our manuscript 

 and has made corrections and suggestions of great value. In the 

 discussion of the species of Cladophora, a field in which he has 

 gained great proficiency, he has added some notes which will go 

 a long way toward straightening out the confusion hitherto 

 existing. Through him, also, Dr. T. E. Hazen has examined 

 the greater part of our Ulothricacea? and Chsetophoraceae, and 

 aided us with determinations and critical notes. 



Family ZYGNEMACE^. 



Zygnema chalybeospermum Hansgirg. 



In waterfalls in a creek. Port Renfrew, B.C., Tilden, No. 392 ! 



Miss Tilden says that the specimens do not agree with this 

 species, but that the smooth median membrane of the zygote and 

 the apparently scalariform conjugation bring it nearer to this 

 than to any other. In our copy of the American Algae, little is to 

 be determined on account of the poor condition of the specimen 

 distributed. 



Spirogyra longata (Vaucher) Kuetzing. 



Abundant in ditches of fresh, or even of slightly brackish 

 water. Near LaConner, Wash., F.L.G., No. 340!; Seattle, 

 Wash., N.L.G., Nos. 664!, 665! 



Good fruiting material was gathered in May, and both lateral 

 and scalariform conjugation was observed. 



Spirogyra porticalis (Mueller) Cleve. 



In running water. Popof Island, Alaska, Saunders (1901, 

 p. 409). 



Spirogyra catenseformis (Hassall) Kuetzing. 



In a pond of slightly brackish water. Swan town, Whidbey 

 Islaud, Wash., N.L.G., No. 417! 



