Plankton Algae of the Upper Des Moines River, Iowa

Sedgewick-Rafter quantitative strip counts and proportional counts of Hyrax-mounted diatom slides were made on weekly grab samples taken at one station near Boone, and every other week at four other downstream stations during 1968 and January 1969. Eleven cyanophycean taxa, six green flagellate taxa, three taxa of other pigmented flagellates, and 42 taxa of other green algae were encountered. A total of 185 diatom taxa in 33 genera were identified, 75 of which are new to Des Moines River records. Biddulphia and Thalassiosira are diatom genera new to published records in Iowa