Gomphonema Pygmaeum Guide
Credit: Pat Kociolek
  1. Valves small, narrow
  2. Striae shortened on either side of central area
  3. Striae may be curved at central area
  4. Stigma near proximal raphe ends

Valves are small and narrow. Striae are shortened on either side of the central area, and striae may be curved near the central area. Single, distinct stigma present, positioned near the proximal raphe ends.