Species: Colonies without perforations, 12-74 μm in diam.; all cells with a deep incision,
cell wall smooth ; marginal cells with two triangular processes extending outward, triangular
(colonies with small number of cells) or trapezoid (large colonies) at base, 5-18 μm in diam.,
4-18 μm long; inner cells five to seven angled, 4-16 μm in diam.,
4-14 μm long (Photomicrographs of the Freshwater Algae, vol. 5, 1986).