Abstract
Diatom assemblages were studied from the Toyokawa River, which is located in the central part of Akita Prefecture, northern part of Japan. A total of 78 taxa among 44 genera were recorded. The following 12 taxa were observed from all five stations: Melosira varians, Fragilaria capitellata, Fragilaria vaucheriae, Meridion circulare var. constrictum, Gomphoneis okunoi, Planothidium lanceolatum, Navicula gregaria, Navicula lanceolata, Nitzschia dissipata var. media, Nitzschia inconspicua, Nitzschia tubicola, Surirella angusta. Diatoma tenuis var. moniliformis was recorded in Japan for the first time.
