Gomphoneis Herculeana Guide
Credit: Pat Kociolek
  1. Valves lanceolate-clavate
  2. Longitudinal lines present

Valves are large and robust, strongly lanceolate-clavate with broadly rounded headpole and narrow, rounded footpole. The axial area is narrow and straight. The central area is relatively small, irregularly rounded and bears a single stigma. The longitudinal lines are positioned approximately one-half the way between the axial area and margin.