This variety has been reported as Fragilaria construens var. capitata(Stoermer and Yang 1969). Based on preliminary observations and genus description of Williams and Round (1987), it may be more appropriate in the genus Staurosira. However, further investigation is necessary before the transfer can be made.
The valves of this variety are linear to lanceolate in shape with protracted, capitate ends. Often the middle portion of the valve is constricted (Stoermer and Yang 1969). The ornamentation is similar to that of the nominate variety (Stoermer and Yang 1969).