Euccoconeis Flexella Guide
Credit: Marina Potapova
  1. Frustules large, 18-40 μm long
  2. Frustules strongly bent
  3. Striae 22-24 in 10 μm

Frustules are large and strongly bent. Valves are elliptical-lanceolate with slightly drawn-out ends and deep mantles. The raphe valve has lanceolate-rhomboid central area. The rapheless valve has a large rectangular or hexagonal central area. The striae are strongly radiate on raphe valve and slightly radiate on rapheless valve, 22-24 in 10 μm.