Genus: Filament without branching; cell body cylindrical; each cell wall consists of two parts with "H" structure overlapping at the midregion; chloroplasts many, disc-shaped, without pyrenoids (Guide book to the "Photomicrographs of the Freshwater Algae", 1998). Species: Filament 10-12-(-15) μm wide (Süßwasserflora von Mitteleuropa 3, Xanthophyceae 1, 1978). Filament 8-12 μm wide; many chloroplasts in each cell (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: Kanayama chosei-chi (water reservoir), Kiyose city, Tokyo, Japan, April 20, 2008 by Y. Tsukii