Meridion Lineare Guide
Credit: Loren Bahls
  1. Valves irregular in shape
  2. Forms ribbon-like colonies
  3. Costae perpendicular to apical axis
  4. Striae 16-18 in 10 µm

Valves are isopolar, but slightly irregular in shape. Valves are linear-lanceolate, to oval in smaller specimens. Frustules typically attach to one another in long ribbon-like colonies. Transapical costae are mostly perpendicular to the apical axis and number 4-6 in 10 µm. Striae are distinct and number 16-18 in 10 µm.