Eucocconeis Americana Guide
Credit: Marina Potapova
  1. Valves flat, elliptic-lanceolate
  2. Valves 7.8-13.4 µm wide
  3. Apices subrostrate
  4. Central area on raphe valve large, symmetric, transversely elliptic to rectangular
  5. Central area on rapheless valve large hexagonal

Valves are elliptic-lanceolate with flat faces and subrostrate apices. Valves are 7.8 to 13.4 µm in width. The central area on the raphe valve is large, symmetric and transversely elliptic to rectangular. The raphe is straight to slightly sigmoid with terminal fissures bent in opposite directions. The rapheless valve has a narrow sigmoid axial area and large hexagonal central area.