Phylum: Charophyta   Family: Desmidiaceae

Cosmarium galeritum  Nordstedt

In a European contect, this species seems to prefer an arctic-alpine distribution. Found in neutral to slightly acidic waters in oligo- mesotrophic conditions.

References: 
West, W. & West, G.S. (1905) A Monograph of the British Desmidiaceae, Volume 2
John, D.M., Whitton, B.A. & Brook, A.J. (2011 second edition) The Freshwater Algal Flora of the British Isles
Coesel, P.F.M. & Meesters, K.J. (2007) Mesotaeniaceae and Desmidiaceae of the European Lowlands