Genus: Colonies of a fixed number of cells, flat, circular in shape; cell body polygonal in shape,
with horn-like projections; cell wall garanulated, wrinkled or notched;
chloroplasts plate-like or reticular; asexual reproduction by zoospore; sexual reproduction by isogametes
(Illustrations of The Japanese Fresh-water Algae, 1977).
Species: (Photomicrographs of the Freshwater Algae, vol. 5, 1986).