Genus: Filamentous algae without branching; a single plate-like chloroplast in each cell (Illustrations of The Japanese Fresh-water Algae, 1977). Species: Cell body 30-140 μm long, 8-13 μm wide; 4-8 pyrenoids in each cell; zygotes spherical, 13-25 μm diam. (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: No.2, Kashibaru marsh, Karatsu city, Saga Pref., Japan, November 22, 2006 by Y. Tsukii