Pinnularia Nodosa Guide
Credit: Loren Bahls
  1. Valve margins triundulate
  2. Apices subcapitate
  3. Valve surface mottled

Pinnularia nodosa has linear valves, with triundulate margins. The apices are broad and subcapitate. The surface of the valve is mottled. The valve width ranges from 7.6 to 9.1 ┬Ám.