Closterium karnakense
image © Alfred van Geest

Closterium karnakense. Notice gracefully curved cell only for a small part filled in by chloroplasts.
Cell dimensions (L x B): 270 x 21 µm

Closterium karnakense
image © Alfred van Geest

Cl. karnakense detail of cell end. Notice narrowly rounded apex.



 


Desmid of the Month
January 2026

Closterium karnakense


Closterium karnakense may be compared with Cl. dianae (desmid of August 2025). Both species are characterized by evenly curved, graceful cells. However, whereas cell apices in Cl. dianae are obliquely truncate with a distinct end-pore, those in Cl. karnakense are more rounded and destitute of such a pore. Most important feature in Cl. karnakense however is the relative small size of the chloroplast filling in only about half the cell. Moreover, whereas Cl. dianae is characteristic of mesotrophic freshwaters, Cl. karnakense is met with in eutrophic, usually a bit saline habitats. In the Netherlands, it is only known from a few sites.

Closterium karnakense
image © Ronald Luts (after Flemish material).

Another cell of Cl. karnakense with somewhat larger chloroplasts (but still taking up little space).


Closterium karnakense
Image © Roland Luts (after Flemish material)

Bloom of Cl. karnakense demonstrating the constant appearance of the chloroplast.