Desmidium grevillei

Contrary to Desmidium swartzii (desmid of the month of August 2003) cells of Desmidium grevillei *  in top view are not triangular (triradiate) but ellipsoid (so biradiate) in shape. As we have to do with a species in which the cells are united to form twisting filaments, series of cells are alternatingly faced in relatively broad frontal view and in relatively narrow lateral view (and transitional phases in between) resulting into a filament with a seemingly varying diameter.

In the Netherlands D. grevillei is a rare species, confined to acidic, oligotrophic moorland pools.

* Synonym: Desmidium cylindricum

Filament of Desmidium grevillei displaying both cells in frontal and in lateral view.

Dimensions of a single cell in frontal view (L x B): ca 25 x 50 µm

<< Image left:

Detail of filament showing an oval outline of cells in frontal view and a rectangular outline of cells in lateral view.

Image © Henk Schulp

Image on the right:

Overview of some three colonies of Desmidium grevillei showing torsion of the filaments. Note also gelatinous sheaths enclosing the filaments. 

Image © Wim van Egmond