Gomphonema Truncatum Guide
Credit: Pat Kociolek
  1. Valves clavate
  2. Headpole capitate
  3. Central area “bow-tie” shaped

Valves clavate, with a tumid center. A constriction at the headpole forms a distinct capitate apex. The central area is “bow-tie” shaped. A single stigma is present. Striae are radiate, indistinctly punctate and become parallel toward the headpole and strongly radiate at the footpole. A distinct apical pore field is present at the footpole.