Navicula Flatheadensis Guide
Credit: Loren Bahls
  1. Valves lanceolate, 10.3-13.5 ┬Ám wide
  2. Valve apices weakly protracted
  3. Proximal raphe ends distant
  4. Central nodule with one or both sides convex
  5. Terminal striae weakly convergent

Valves are lanceolate and wider than 10 microns. Valve apices are relatively wide, weakly protracted, and rounded. The proximal raphe ends are distant. The central nodule is typically asymmetric, with one flat side and one convex side. Striae become parallel and then weakly convergent at the valve apices.