IOWA ACADEMY OF SCIENCE 
53 
KEY TO THE SPECIES. 
Diameter of cells 3.3u-3.8u M. glauca 
Diameter of cells 6.5-9.5u M. elegans 
2. M. glauca. (Ehrenb.) Naeg. 
This alga is common floating in the quiet waters of ponds. 
Ames, 1884? C. E. Bessey. (As M. nova). 
Grinnell and Fayette. Bruce Fink. 
Eagle Grove, Hewitt’s Pond. ’04. R. E. Buchanan. 
3. M. elegans A. Br. 
A form agreeing with this species in all essential characteristics has 
been once collected. Cells 7u in diameter. 
Eagle Grove. Slough bottom. 1904. R. E. Buchanan. 
2. Coelosphaerium. 
h. C. kuetzingianum Naeg. 
A frequent alga in many permanent ponds, often floating in considerable 
quantities in the lakes. 
South Gar Lake. Dickinson Co. 1904. R. E. Buchanan. 
Eagle Grove. Hewitt’s Pond. 1904. R. E. Buchanan. 
Eagle Grove. Margin of Slough. 1904. R. E. Buchanan. 
Collections have been made several times since in similar locali- 
ties around Eagle Grove. 
3. Gomphosphaeria. 
5. G. aponina Kutz. 
Found once only. Should be common in stagnant water. 
Eagle Grove. Stagnant Pool. 1904. R. E. Buchanan. 
4. Microcystis. 
6. M. aeruginosa. 
Very abundant in the first locality. 
East Okoboji Lake. Oct. 1904. R. E. Buchanan. 
Ames. 1884. C. E. Bessey. 
5. Gloeocapsa. 
KEY TO THE SPECIES. 
Integuments colorless. Cells 2-4u in diameter G. arenaria 
Integuments yellow to brown G. magma 
7. G. arenaria. 
Forms thin aeruginous coating on damp stone, etc. 
Grinnell. 1905. Dr. Bruce Fink. 
Ames. Abundant on flower pots in greenhouse. 1904. R. E. Buchanan. 
8. G. magma. 
Fayette. On granitic boulders. Bruce Fink. 
6. Aphanocapsa. 
9. Grevillei? (Hass.) Rabenh. 
A form referred to this species has been found once in stagnant water. 
Ames. Pond, near R. R. 1905. R. E. Buchanan. 
7. Porphyridium. 
10. P. cruentum. (Ag.) Naeg. 
