Desmid of the month
December 2006

Closterium setaceum

As indicated already by its name, Closterium setaceum is marked by extended, setalike cell ends. In this feature it resembles related species like Cl. kuetzingii and Cl. rostratum. However as compared to those species, the colourless extensions in Cl. setaceum are relatively longer, i.e. longer than the green, inflated midregion of the cell. Zygospores of Cl. setaceum are very characteristic, i.e., about cruciform with deeply concave sides and truncate angles. In the Netherlands, Cl. setaceum is a rare species of acidic, oligotrophic bogs and moorland pools. Zygospores have been encountered only incidentally.

<< Image on the left:

Cell of Closterium setaceum characterized by very long, colourless, beak-like cell ends and a green, fusiform midregion.

Cell dimensions (L x B): 370 x 10 µm

Zygospore of Closterium setaceum (entangled in detritus). The empty gametangial cells are still firmly attached to the truncate angles of the cruciate spore.