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).
Images of collecting locality:
waterfield between Kita-Omachi station and Nogu river, Omachi city, Nagano Pref., Japan, June 4, 2007 by Y. Tsukii