Genus: Colony within a gelatinous bag; cells uniformly arranged at the peripheral matrix; cell body spherical or ellipsoidal with 2 pseudo-flagella; 2-4 cells form a small subset; a single chloroplast cup-shaped, with a pyrenoid (Guide book to the "Photomicrographs of the Freshwater Algae", 1998). Small colonies planktonic or large ones attached to other substrates (Illustrations of The Japanese Fresh-water Algae, 1977). Species:

31 μm 63 μm 94 μm; x 640

Images of collecting locality: Kawaguchi Natural Park, Sashima, Kawaguchi city, Saitama Pref., Japan, February 5, 2006 by Y. Tsukii