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: Filaments 5-6 μm wide, up to 14 times longer than the width; chloroplasts 2 or 3 in number, elongated plate-like (Süßwasserflora von Mitteleuropa 3, Xanthophyceae 1, 1978).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: Gunma-no-suigo-koen (park), Itakura town, Gunma Pref., Japan, February 18, 2006 by Y. Tsukii