Phylum: Charophyta   Family: Desmidiaceae

Cosmarium botrytis G.G.A. Meneghini ex J. Ralfs 1848

First described and illustrated by Meneghini in Ralfs (1848: 99, pl. 16: fig. 1). This species has spawned many varieties but the nominate variety is the most widespread. It should be compared closely with Cosmarium ochthodes.
Cell dimensions: L: 60-90 µm; B: 48-68 µm.; Is: 15-20 µm; Th: 30-36 µm, L/B: 1.15-1.30.
Rather common in slightly acidic to slightly alkaline waters, found in the plankton and marginal vegetation of lochs, and from atmophytic habitats.

References: 
Kouwets, F.A.C. (in manuscript) European Flora of the Desmid Genus Cosmarium.
Ralfs, J. (1848) The British Desmidieae.
West, W. & West, G.S. (1912) A Monograph of the British Desmidiaceae, Volume 4.