Coelastrum microporum Nägeli var. microporum: Colonies of 8, 16, 32 or 64 cells, spherical or ovoid in shape, covered by a delicate gelatinous sheath; cells connected to adjacent ones by the basal part of the cell; intercellular spaces triangular and smaller than cell diam.; cells 3-20 μm diam. (Photomicrographs of the Freshwater Algae, 1996).