Gomphonema Olivaceoides Hutchinsoniana Guide2
  1. Valve clavate
  2. Headpole subrostrate to subcapitate
  3. Footpole capitate
  4. Four isolated stigmoids bordering central area

Valves are clavate, with a subrostrate to subcapitate headpole. The footpole is capitate. The central area is bordered by four isolated stigmoids.