Phylum: Charophyta   Family: Desmidiaceae

Cosmarium quadrifarium P. Lundell

A widespread but seemingly rare species found in the tychoplankton of lochans and pools, also found in mountainous regions.

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