Decussata Guide
Credit: Pat Kociolek
  1. Valves linear to linear-lanceolate
  2. Striae punctate
  3. Striae decussate

Decussata valves are linear to linear-lanceolate, with slightly rostrate ends. The striae are punctate, comprised of distinct, round areolae. The striae are decussate, meaning they appear to be organized into rows - a transapical row and two oblique rows.

Decussata includes two species, including the former Navicula placenta. Decussata placenta grows in low nutrient, slightly acidic seeps in Iowa. It is also known from moss and aerophilic habitats.