Phylum: Charophyta   Family: Desmidiaceae

Cosmarium meneghinii L.A. de Brébisson ex J. Ralfs 1848

First described by Brébisson and illustrated by Jenner in Ralfs (1848: 96, pl. 15: 6). The size parameters have moved considerably since Brébisson first described it. It is currently regarded as a species complex.
Cell dimensions: L: 14-21 µm; B: 11-18 µm; Is: 3.5-5 µm; Th: 7-10 µm; L/B: 1.13-1.32.
Found in the plankton of moorland pools and lochs; also, in ephemeral winter floods. A widespread species but not as common as it was once reported, especially for Scotland generally.

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. (1908) A Monograph of the British Desmidiaceae, Volume 3.