Navicula Subconcentrica Guide
Credit: Loren Bahls
  1. Valves lanceolate
  2. Valve ends narrow, acutely rounded to subcapitate
  3. Proximal raphe ends straight
  4. Central nodule with flat, or concave sides

Navicula subconcentrica has lanceolate valves that are less than 11 ┬Ám wide. Valve ends are narrow and acutely rounded, to subcapitate. The proximal raphe ends are nearly straight and relatively close together. The central nodule is typically symmetric, with flat or slightly concave sides.