Fistulifera Iconic
  1. Frustules very lightly silicified
  2. Striae not visible with light microscopy
  3. Central sternum distinct

The frustules of Fistulifera are very lightly silicified. Valves range in shape from linear to elliptical. Cells are small (usually < 8 µm) and possess numerous thin girdle bands, up to fourteen or more. Striae are not visible with light microscopy. The central sternum is distinct and may remain in a sample after the thin frustule has been destroyed in standard preparation.

Fistulifera includes the former Navicula pelliculosa (Bréb.) Hilse and N. saprophila Lange-Bert. These species grow in a wide range of freshwaters and they may be often overlooked because of their small size and light silicification. Fistulifera can reach high abundance in eutrophic and polluted waters.