Desmid of the month
August 2022

Closterium turgidum

Cl. turgidum is a very large-sized Closterium species with slightly curved cells that gradually attenuate from the midregion to the poles. Main characteristic is the shape of the cell ends. On the ventral side of the cell just below the apex those ends are obliquely truncate, on the dorsal side slightly hollowed giving the impression of being somewhat recurved. Cell wall is finely striate, without girdle bands. In the Netherlands, Closterium turgidum is a rather rare species, predominantly known from mesotrophic fen hollows.

Closterium turgidum. Notice large, slightly curved cell with somewhat recurved ends.

Cell dimensions (L x B): ca 770 x 60 µm

Closterium turgidum, detail of cell end. Notice obliquely truncate apex.

Image © Alfred van Geest

Closterium turgidum, detail of midregion. Notice delicate striation of the wall.