Cosmarium cosmarioides. Notice broadly cylindrical cell outline and shallow, open sinus.

Cell dimensions (L x B): 115 x 50 µm



Desmid of the month
October 2022

Cosmarium cosmarioides *

C. cosmarioides is a large-sized, smooth-walled Cosmarium species readily to be recognized by its broadly cylindrical cell outline and a shallow, open sinus. Chloroplasts are in the form of longitudinal, parietal bands with numerous papillate lobules protruding against the inner side of the cell wall. In the Netherlands, Cosmarium cosmarioides is mainly found in mesotrophic quaking fen hollows, elsewhere rare.

* Cosmarium cosmarioides (De Bary) Růžička is better known under the name of Cosmarium debaryi Archer

Image © Alfred van Geest

C. cosmarioides. Notice parietal chloroplast bands with small lobules protruding against the cell wall.

Cell of C. cosmarioides showing chloroplast lobules in top view.