Genus: Filamentous algae without branching, no rhizoids, covered with gelatinous sheath; cell body cylindrical or ellipsoidal, cells attached side by side or separated; a single chloroplast band-form, with a pyrenoid (Guide book to the "Photomicrographs of the Freshwater Algae", 1998). Species: Filament covered with a thick gelatinous coat; 2 or 4 cells closely contacted; cell body elongated ellipsoid or ovoid, 4-6 μm long, 7-9 μm wide; chloroplasts parietal, with a single pyrenoid (Photomicrographs of the Freshwater Algae, vol.4, 1985).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: Koyama river near railway bridge of Hachiko-sen (JR), Hiroki, Misato town, Saitama Pref., Japan, April 15, 2006 by Y. Tsukii