Diadesmis

Kützing 1844      Category: Symmetrical biraphid
TYPE SPECIES: Diadesmis confervacea Kützing

Denticula

 

Diatoma

Image Credit: Marina Potapova, Eugene Stoermer and Sarah Spaulding

CLASS: Bacillariophyceae
  ORDER: Naviculales
    FAMILY: Diadesmidaceae

  1. Areolae elongate
  2. Frustules small, usually less than 20 µm in length
  3. Cells form band-like colonies

Diadesmis is biraphid, although the raphe often becomes secondarily filled with silica. Frustules of Diadesmis are small, usually less than 30 µm in length. The striae are composed of areolae elongated in the transapical direction, a characteristic that may be difficult to discern in the LM. Frustules form band-like colonies, which may be linked by marginal spines. The raphe systems of many frustules are secondarily filled with silica, and a raphe may not be evident in valve view. In girdle view, however, a central nodule and helictoglossa may be seen - evidence of the presence of a raphe. Living cells contain single, slightly lobed plastid.

Diadesmis is considered an aerophilic taxon. It grows on mosses and on damp rocks, often in low conductivity, slightly acid waters.

Cite This Page:
Spaulding, S., and Edlund, M. (2008). Diadesmis. In Diatoms of the United States. Retrieved October 31, 2014, from http://westerndiatoms.colorado.edu/taxa/genus/Diadesmis

Contributor: Sarah Spaulding | Mark Edlund - December 2008