Synedra

Ehrenberg 1830      Category: Araphid
TYPE SPECIES: Synedra ulna (Nitzsch) Ehrenberg

Surirella

 

Tabellaria

Image Credit: Sarah Spaulding

CLASS: Fragilariophyceae
  ORDER: Fragilariales
    FAMILY: Fragilariaceae

  1. Vales linear to lanceolate with rounded ends
  2. Striae parallel
  3. Apical porefield present at each pole

Currently, species in Synedra are considered to be primarily marine, typified by S. balthica, which is synonomous with Synedra gaillonii (Bory) Ehrenberg. The taxon shown here is S. gaillonii. Following recent changes in the literature, elongate, needle-like freshwater species on the Diatoms of the United States site are treated in Fragilaria and Ulnaria.

Araphid genera, including Synedra, Fragilaria, Ulnaria and others, have been subject to a longstanding debate concerning nomenclature (Williams 2011). Historically, Fragilaria and Synedra were distinguished based on their growth form. Synedra included taxa that produced stellate colonies that attached to subtrates by a mucilage pad. Those taxa are now largely included in Ulnaria, but many have yet to be transferred. Compare also with the genus Fragilaria, which also includes linear, elongate valves that form ribbon-like colonies.

Cite This Page:
Spaulding, S., and Edlund, M. (2015). Synedra. In Diatoms of the United States. Retrieved February 13, 2016, from http://westerndiatoms.colorado.edu/taxa/genus/Synedra

Contributor: Sarah Spaulding | Mark Edlund - November 2015

 

November 5th, 2015 - Change in genus circumscription

Previous to this update, the genus Synedra was presented on Diatoms of the US include a variety of freshwater species. For example, Synedra included taxa that produced stellate colonies that attached to subtrates by a mucilage pad. Following the establishment of Ulnaria (Kützing) Compère 2001, most freshwater species are in the process of being transferred to Ulnaria. S. Spaulding