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).