Genus: Filament without branching; cell body very long, cylindrical in shape, with many ring-shaped chloroplasts; sexual reproduction by oocyte and sperm (Guide book to the "Photomicrographs of the Freshwater Algae", 1998). Species: Filamentous algae without branching; cell body cylindrical, very long, 300-500 μm long, 30-50 μm wide, with many nuclei (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640