Genus: Unicellular; variable in shape; a constriction at the center of the cell body;
mostly longer than wide; flattened; each semicell hemispherical, spherical, ellipsoidal,
rectangular, pyramidal or kidney-shaped; no apical indentation
(Illustrations of The Japanese Fresh-water Algae, 1977).
Images of collecting locality:
No. 2, Ohdo-ike park, Chuo-ku, Chiba City, Chiba Pref., Japan, December 24, 2007 by Y. Tsukii