Genus: Flattened colonies of 16 or 8 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).