Stephanodiscus

Ehrenberg 1845      Category: Centric
TYPE SPECIES: Stephanodiscus niagarae Ehrenberg

Stephanocyclus

 

Surirella

CLASS: Coscinodiscophyceae
  ORDER: Thalassiosirales
    FAMILY: Stephanodiscaceae

  1. Striae radial and organized into fasicles
  2. Spines marginal
  3. Valve face flat or concentrically undulate
  4. Marginal spines may be subtended by marginal fultoportulae

The valve face of Stephanodiscus species is flat or concentrically undulate.The striae are radial and organized into bundles, or fasicles. Fasicles are separated from one another by costae. Spines are present on the valve margin and a marginal fultoportula may be positioned below the spines. Internally, the areolae are covered by domed cribra.

Stephanodiscus is a diverse and widespread planktonic genus of freshwaters, primarily lentic (lake) habitats. Many species are variable in morphology (polymorphic) in response to the concentration of dissolved silica in the surrounding waters. Rapid speciation within the genus has been demonstrated based on sediment records in Yellowstone Lake, Wyoming.

Cite This Page:
Spaulding, S., and Edlund, M. (2008). Stephanodiscus. In Diatoms of the United States. Retrieved September 02, 2014, from http://westerndiatoms.colorado.edu/taxa/genus/Stephanodiscus

Contributor: Sarah Spaulding | Mark Edlund - December 2008