Geissleria

Lange-Bertalot et Metzeltin 1996      Category: Symmetrical biraphid
TYPE SPECIES: Geissleria moseri Metzeltin Witkowski et Lange-Bertalot in Lange-Bertalot et Metzeltin

Frustulia

 

Gomphoneis

Image Credit: Marina Potapova

CLASS: Bacillariophyceae
  ORDER: Naviculales
    FAMILY:

  1. Annulae present at poles
  2. Isolated punctum present or absent in the central area
  3. Valve elliptical or linear-elliptical with rounded or rostrate ends

Geissleria valves are elliptical to linear-elliptical, becoming obtuse, broadly rounded or rostrate at the ends. The striae are comprised of fine lineolate areolae; aerolae 50-80 in 10 µm. Distinctive annulae are present at the poles. The annulae are comprised of one to four transapical striae that interrupt the typical striae. The raphe is straight and filiform, with straight proximal ends. Terminal raphe ends are deflected. An isolated punctum may be present or absent in the central area.

Geissleria includes species that were formerly included in the ‘Annulatae’ section of Navicula, including Navicula paludosa (Hustedt) andN. similis Krasske. Geissleria species are broadly distributed over a range of oliogotrophic to eutrophic waters, but are locally rare in abundance. Species level ecological preferences may be more specific.

Cite This Page:
Spaulding, S., and Edlund, M. (2009). Geissleria. In Diatoms of the United States. Retrieved August 01, 2014, from http://westerndiatoms.colorado.edu/taxa/genus/Geissleria

Contributor: Sarah Spaulding | Mark Edlund - January 2009