Cymbella C.A. Agardh


Frustules biraphid, asymmetrical to the apical axis, symmetrical to the transapical axis. Dorsiventrality slight (with some species approaching naviculoid symmetry) or pronounced. Raphe centrally located or eccentric. Stigmata lacking or on the ventral side of the central area. Distal raphe ends straight or deflected dorsally. Cells benthic, free or in mucilage, or growing at the ends of mucilaginous stalks. Apical pore fields at both poles or lacking.

The broad sense of Cymbella embraced here (and in recent treatments of the genus, e.g. Krammer 1982; Krammer and Lange-Bertalot 1986; Round et al. 1990), is probably not a natural group of taxa. It contains everything that is not referred to Encyonema or Reimeria. A natural group within Cymbella contains those species with ventrally-placed stigmata, dorsally deflected external distal raphe ends and apical pore fields.

Light Microscope Image(s)

Each image is accompanied by the genus and species, California Academy of Sciences slide number (ie. CAS 612010), location of the specimen on the slide, and dimension in microns.