Guide to Pinnularia kwacksii
- Axial area wide
- Valves linear
- Longitudinal line present
- Striae slightly radiate in center
Valves are linear, with broadly rounded apices. The axial area is broad, about 1/2 the width of the vale. Striae are slightly radiate in the center, slightly convergent at the apices, and a longitude line crosses the striae.