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: A linear short filament, straight or slightly curved, covered with a mucilagenous sheath having a radiating strands (only visible when stained); planktonic; cell body cylidrica, straight or slightly curved, both ends rounded, 8-10 μm long, 3-3.5 μm wide; a single chloroplast parietal, plate-like, extending at both ends, without pyrenoids; 1 or several granules present within vacuoles located at both ends of the cell (Photomicrographs of the Freshwater Algae, vol. 13 (1994).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: No.2, Maimeno-ike (pond), Norikura highland, Azumi, Matsumoto city, Nagano Pref., Japan, November 4, 2007 by Y. Tsukii