Phylum: Charophyta   Family: DEsmidiaceae

Cosmarium subarctoum (Lagerheim) Raciborski 1892

A rare desmid with probably and arctic-alpine distribution. It may well be overlooked or confused with other small desmids with a broad isthmus. West & West (1908, p. 31, pl. 68: 6-8) have recorded it from a loch on the Isle of Harris.

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.