PLANTS OF IOWA 85 



1026a. G. acuminatum, Ehrb. 



NAVICULACE^E FAMILY. 



Navicula. 



1027. N. nobilis, Kutz. 

 1027a. N. peregrina, Kuetz. 

 1027&. N. viridis, Kutz. 



Stauroneis. 



1028. S. phoenecentcran, Ehrb. 

 Pleurosigma. 



1029. P. attenuatum. 



COCCONEMACEiE FAMILY. 



Amphora. 



1030. A. oralis, Kuta. 

 Ponds. 



CYMBELLE^ FAMILY. 



Cymbella. 



1031. C. ehrenbergii. 



HETEROKONTAE. 



TRIBONEMACE.E FAMILY. 



Tribonema. 



1032. T. bombycinum, (Agardh.) Derb. & Sol. 



Very common in stagnant water, and even slow flowing 

 water and springs. 



1033. T. bombycinum tenue, Hazen. 

 Slough; in pond amid Lemna. 



1034. T. utriculosum, (Kutz.) Hazen. 

 In rain barrels and in ponds. 



BOTRYDIACE^E FAMILY. 



Botrydium, Wallr. 



1035. B. granulatum, (L.) Grev. 



Occurs abundantly on mud jusl drying up. such M that 



