Phylum: Charophyta   Family: Desmidiaceae

Cosmarium turpinii var. eximium West & G.S. West

Differs from the nominate in having smaller cells with a single protuberance and a large isthmial granule. However, the size range for this sample is below those quoted by the Wests (1908) and Kouwets (in manuscript) and closely matches that of Borge’s (1913) forma minor. I suspect this is just a slightly smaller form of eximium. A rare variety with only two or three Scottish record. It prefers circumneutral waters

References: 
West, W. & West, G.S. (1908) A Monograph of the British Desmidiaceae, Volume 3
Kouwets, F.A.C. (in manuscript) European Flora of the Desmid Genus Cosmarium
Borge, O. (1913) Beiträge zur Algenflora von Schweden. 2. Die Algenflora um den Torne-Träsksee in Schwedisch-Lappland