Chaemapinnularia Guide
Credit: Marina Potapova and Sarah Spaulding
  1. Striae composed of chamber-like areolae
  2. Externally, areolae covered by vela

The valve margins of Chamaepinnularia are linear, nearly linear, or undulate. Cells are small, usually less than 25 µm in length and 4 µm in breadth. The striae are composed of simple, chamber-like areolae, with external openings covered by vela. Internally, the areola openings are divided with internal plates of silica. The raphe system may be simple or complex in structure, as in Pinnularia or Navicula. Externally, the distal raphe fissures are hooked, and terminate internally with a small helictoglossa. The external proximal raphe ends are inconspicuous. Internally, the proximal ends are unilaterally hooked.

Cells grow singly, rather than in colonies. Many of the species are aerophilic and grow in splash-zones of streams, moist mosses and lichen habitats. The genus includes a number of smaller species formerly part of Navicula, including N. soehrensis Krasske.