Phylum: Charophyta   Family: Desmidiaceae

Cosmarium kirchneri  Børgesen

A rare species found in the margins and plankton of lochs. Very similar to Cosmarium margaritiferum but with more rounded semicells and more organised granules. West & West (1908) have it as a form of Cosmarium margaritiferum and record it as unknown in Britain at the time

References: 
Kouwets, F.A.C. (in manuscript) European Flora of the Desmid Genus Cosmarium
West, W. & West, G.S. (1908) A Monograph of the British Desmidiaceae, Volume 3
Coesel, P.F.M. & Meesters, K.J. (2007) Mesotaeniaceae and Desmidiaceae of the European Lowlands