Gomphonema Freesei Guide
Credit: Sylvia Lee, Mark Edlund
  1. Valves clavate-lanceolate
  2. Axial area broad
  3. Striae weakly radiate
  4. Stigmoid present
  5. Areolae coarse

Valves are clavate-lanceolate, with convex margins near headpole and evenly tapered to narrower, acutely rounded footpole. The axial area is broadly lanceolate, expanded to an apically elliptic central area. A single stigmoid is positioned near the proximal raphe ends. Striae are short and evenly spaced, subparallel in the central area, slightly radiate and subparallel to convergent at headpole. Striae are coarsely areolate. The apical pore field is large and evident.