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Diatoms of the United States is now known as Diatoms of North America.
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Mann and Stickle in Round, Crawford and Mann 1990      Category: Symmetrical biraphid
TYPE SPECIES: Cavinula cocconeiformis Mann and Stickle in Round, Crawford and Mann




Image Credit: Eduardo Morales, Ditmar Metzeltin

CLASS: Bacillariophyceae
  ORDER: Naviculales
    FAMILY: Cavinulaceae

  1. Valves linear-lanceolate to nearly circular
  2. Striae uniseriate
  3. Striae radial
  4. Terminal raphe fissures absent

Species of Cavinula are characterized by uniseriate, radial striae composed of round to elongate areolae. Valves are linear-lanceolate to nearly circular in outline. Internally, the central sternum is thickened, a feature visible in SEM. Externally, the proximal raphe is expanded, while the internal proximal raphe ends are straight. The terminal raphe fissures are absent. 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.

Cite This Page:
Spaulding, S., Edlund, M., Morales, E., and Metzeltin, D. (2009). Cavinula. In Diatoms of the United States. Retrieved May 22, 2018, from

Contributor: Sarah Spaulding | Mark Edlund | Eduardo A. Morales | Ditmar Metzeltin - January 2009
Reviewer: Sam Rushforth - April 2010