Navicula Rostellata Guide
Credit: Marina Potapova
  1. Valves linear to linear-lanceolate with subrostrate apices
  2. Proximal raphe ends bent
  3. Central nodule expanded to primary side
  4. Central striae radiate, bent
  5. Areolae ~ 30 in 10 μm

Valves are linear to linear-lanceolate with subrostrate apices. The central area is often slightly asymmetrical. The raphe is straight, with external proximal raphe ends slightly dilated and bent towards primary side of the valve. The central nodule is asymmetrically expanded on the internal valve surface to the primary side. Striae are radiate and bent around the center, 12-14 in 10 µm, becoming parallel, then convergent at the apices.