Gomphonema Mexicanum Guide
Credit: Pat Kociolek
  1. Valves elliptical-clavate
  2. Headpole slightly produced, broadly rostrate
  3. Axial area straight
  4. Stigma offset

Valves are elliptical-clavate. The headpole is slightly produced and broadly rostrate, while the footpole is rounded. The stigma opening on the inside is quite offset from the external opening. Striae are punctate, parallel to radiate and strongly radiate at the footpole. Septa and pseudosepta are present at the poles.