Diatoms of North AmericaDiatoms of North America
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Guide to Cavinula

D.G.Mann and Stickle in Round, Crawford and D.G.Mann 1990

Cavinula Guide
Credit: Eduardo Morales, Ditmar Metzeltin
  1. Valves linear-lanceolate to nearly circular
  2. Striae uniseriate
  3. Striae radial
  4. Terminal raphe fissures absent

Valves are characterized by uniseriate, radial striae composed of round to elongate areolae. Valves are linear-lanceolate to nearly circular in outline. Externally, the proximal raphe ends are expanded, while the internal proximal raphe ends are straight. Terminal raphe fissures are absent. Internally, the central sternum is thickened. One or two chloroplasts are present in living cells, which are H-shaped in girdle view.

This genus is known from oligotrophic lakes and moist subaerial habitats across the United States. It includes the former Navicula cocconeiformis Gregory and its allies.