This taxon has a linear-lanceolate valve and it tapers into rounded ends. The axial area of this taxon is narrow and it widens toward the central area. The striae are radiate toward the center and convergent at the ends. They are also coarsely linear and sometimes form irregular longitudinal lines. The main characteristics of this taxon are a large central area and large terminal nodules (Patrick and Reimer 1966).
This taxon prefers fresh water and is mesotrophic. It is found in lakes, ponds, springs, streams, lagoons, and thermal springs. The pH it prefers is 4.0 to 6.5 (Patrick and Reimer 1966;Beaver 1981).