Sellaphora Americana Guide
Credit: Loren Bahls
  1. Valves broadly linear
  2. Apices obtusely rounded
  3. Striae evenly spaced throughout
  4. Conopea wide
  5. Central area rounded

Sellaphora americana has large broadly linear valves with obtusely rounded apices. Wide conopea border the narrow axial area and rounded central area. Central striae and distal striae have about the same spacing.