Gomphoneis

Cleve 1894      Category: Asymmetrical biraphid
TYPE SPECIES: Gomphoneis elegans Cleve

Geissleria

 

Gomphonema

Image Credit: Marina Potapova and Sarah Spaulding

CLASS: Bacillariophyceae
  ORDER: Cymbellales
    FAMILY: Gomphonemataceae

  1. Valves clavate, symmetric to the apical axis
  2. Pseudoseptae present
  3. Longitudinal lines may be present
  4. Striae multiseriate

Gomphoneis valves are clavate in both valve and girdle view. Valves are symmetrical to the apical axis. Two distinct groups are currently included within the genus Gomphoneis. One group contains species (including G. herculeana and G. eriense) with multiseriate striae crossed by longitudinal lines and with stigmata. The longitudinal lines are formed by either marginal lamellae or an axial plate, both internal structures that cover the internal expression of the striae. The second group contains species (including G. olivacea and G. quadripunctata) that possess multiseriate striae, but the areolae are indistinct in under the light microscope. This group lacks longitudinal lines and has a variable number of stigmata, from 0-4. Both groups possess septae and pseudoseptae. The foot pole contains an apical pore field, bisected by the terminal raphe ends.

Cells form mucilaginous stalks, joined together into large colonies. In the United States, Gomphoneis is especially diverse in lakes and rivers of midwestern and western states.

Cite This Page:
Spaulding, S., and Edlund, M. (2009). Gomphoneis. In Diatoms of the United States. Retrieved December 22, 2014, from http://westerndiatoms.colorado.edu/taxa/genus/Gomphoneis

Contributor: Sarah Spaulding | Mark Edlund - January 2009