Genus: Flattened colonies of 4 cells embedded in gelatinous sheaths;
cells nearly sphearical, with two flagella of equal length, a stigma and two contractile vacuoles;
a single chloroplast cup-shaped, with a single or several pyrenoids;
asexual reproduction by autocolony formation, each cell divides into a daughter colony;
sexual reproduction isogamous (Photomicrographs of the Freshwater Algae, vol. 2, 1984).
Species: Colonies consisting of 4 cells, up to 20-50 μm in width; cell body pear-shaped, up to 10-22 μm long, 6-16 μm wide. (Photomicrographs of the Freshwater Algae, vol. 2, 1984).
Images of collecting locality:
Old Sugata river, Yasuzuka, Mibu town, Tochigi Pref., Japan, May 5, 2008 by Y. Tsukii