Family (Scenedesmaceae): Colonies of a fixed number of cells (4, 8, 16, 32, or more) arranged 2- or 3-dimensionally; cells spherical, ellipsoidal, polygonal, etc. in shape; chloroplasts 1 or several, plate-like in shape, with 1 pyrenoid; reproduction only by asexual autospores. 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:

50 μm 100 μm 150 μm; x 400 : 31 μm 63 μm 94 μm; x 640

Coelastrum sphericum Nägeli var. sphericum: Colonies of 8, 16, or 32 cells, spherical or ovoid in shape; cells ovoid or cone-shaped, covered with a delicate gelatinous sheath; cells connected to one another by short gelatinous processes; inter cellular space small triangular; cells 6-25 μm diam. (Photomicrographs of the Freshwater Algae, 1996).