Genus: Colonies spherical, with inner empty space; cells attached to each other by a protrusion of cell wall, arranged in a single layer; cell body mostly spherical with some conical or grobular bulges; chloroplasts cup-shaped with a pyrenoid; reproduction by asexual coenobium (Illustrations of The Japanese Fresh-water Algae, 1977). Species: Spherical colonies of 8, 16 or more cells within a gelatinous coat; cell body spherical 9-10 (-24) μm in diam., with 4-10 (-14) small truncate, wart-like processes; cells connected to adjacent ones by the basal stout processes (Photomicrographs of the Freshwater Algae, vol. 5, 1986).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: Chiba Port Park, Chiba City, Chiba Pref., Japan, January 27, 2008 by Y. Tsukii