Genus: Filaments without gelatinous sheath, consisting of up to 20 cells; without rhizoids; (Illustrations of the Japanese Freshwater Algae, 1977). Species: Colonies planktonic, forming short filaments; cells within a trasparent sheath, separated with each other; cell body cylindrical, both ends rounded, 5-9 μm long, 2.8-3 μm in diam.; cell wall thick; a single chloroplast plate-like, parietal; a pyrenoid present but not so conspicuous (Illustrations of the Japanese Freshwater Algae, 1977).

31 μm 63 μm 94 μm; x 640