Genus: Filamentous algae without branching; a single plate-like chloroplast in each cell (Illustrations of The Japanese Fresh-water Algae, 1977). Species: vegetative cells 40-180 μm long, 20-34 μm diam., 4-10 pyrenoids (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: near Lake Aoki, Omachi city, Nagano Pref., Japan, May 8, 2006 by Y. Tsukii