They range in size between 50 and 250 microns. A micron is 1/1000 of a millimeter. Desmids are photosynthetic, and so it had been usual for taxonomists place them in the Kingdom Plantae.

How many cells does a desmid consist of?

Scenedesmus sp. are small forms usually comprised of four cells, but some species may have up to twelve cells. Typically, at least the end cells possess spines. Many species of the genera Cosmarium (left), Euastrum (middle), and Micrasterias (right) have rounded, compressed forms.

What do desmids look like?

Desmids show a wide variety of body shapes and many species are ornamented with all kinds of knobs and spines. There are circular, rotund, elongated, star-shaped and even moon-shaped species, like this Closterium. There are also desmids that form long filaments.