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Guide to Cymbella mexicana

(Ehrenb.) Cleve 1894

Cymbella Mexicana Guide
Credit: Briana Johnson
  1. Valves large, robust
  2. Single, large stigma present
  3. Striae 6-8 in 10 µm in central valve
  4. Areolae adjacent to axial area elongated

Valves are moderately to strongly dorsi-ventral, with rounded apices. A single, large stigma present between the proximal raphe ends, at the central nodule. The striae are coarse and strongly radiate in the center of the valve, becoming parallel near the apices. Typically, three or more striae at the center of the valve are shorter than the others. The areolae are rectangular to circular in shape, with the areolae adjacent to the raphe elongated and triangular in shape. The terminal fissures are dorsally deflected at ~90º.