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Guide to Navicula gregaria

Donkin 1861

Navicula Gregaria Guide
Credit: Marina Potapova
  1. Valves lanceolate with protracted apices
  2. Central area asymmetric
  3. External proximal raphe ends bent toward primary side
  4. Striae slightly radiate around the center
  5. Areolae clearly visible under LM

Valves are lanceolate with protracted apices, 4.1-7.0 µm wide. The central area is asymmetric and elliptic. The external proximal raphe ends are sharply bent toward primary side of the valve. Striae are slightly radiate around the center, numbering 14-18 in 10 µm and are convergent at the apices. The areolae are clearly visible under LM, numbering 25-32 in 10 μm.