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Diatoms of the United States is now known as Diatoms of North America.
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(Krammer) Krammer 1997      Category: Asymmetrical biraphid
TYPE SPECIES: Cymbella subaequalis (Krammer) Krammer




Image Credit: Ditmar Metzelin

CLASS: Bacillariophyceae
  ORDER: Cymbellales
    FAMILY: Cymbellaceae

  1. Valves slightly asymmetric to apical axis
  2. Valves symmetric to transapical axis
  3. Terminal raphe fissures deflected dorsally
  4. Valves lack stigmata and apical pore fields

Cymbopleura frustules are characteristically large and relatively broad in valve outline. The frustules of Cymbopleura are asymmetric to the apical axis, typically with a convex ventral margin and an even broader convex dorsal margin. The striae are composed of rounded areolae. The proximal raphe ends are expanded, while the terminal raphe fissures are hooked and dorsally deflected. Species within Cymbopleura lack apical porefields, therefore they do not produce mucilaginous stalks. Stigmata are absent. Cells grow as single individuals.

Species within Cymbopleura grow in benthic and epipelic habitats and include C. amphicephala, C. ehrenbergii, C. subcapitata, C. inaequalis, Cymbella lata, and the Cymbella heteropleura group.

Cite This Page:
Spaulding, S., Edlund, M., and Metzeltin, D. (2008). Cymbopleura. In Diatoms of the United States. Retrieved May 22, 2018, from

Contributor: Sarah Spaulding | Mark Edlund | Ditmar Metzeltin - December 2008
Reviewer: Sam Rushforth - May 2010