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 30-48 μm long, 10(-15) μm wide , (Süßwasserflora von Mitteleuropa 3, Xanthophyceae 1, 1978).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: Kokai-gawa (Kokai river), Higashitai, Mashiko town, Tochigi Pref., Japan, April 5, 2008 by Y. Tsukii