Guide to Pinnularia divergentissima var. subrostrata
- Apices broadly capitate
- Fascia central, broad
- Central striae strongly radiate
- Distal striae strongly convergent
- Striae with abrupt change in direction
Valve ends are broadly capitate. Central area is a broad fascia reaching the valve margins. Striae are radiate near the valve center, becoming convergent about halfway to the apices. Striae with abrupt change in direction, forming an acute angle between radiate and convergent striae.