Phylum: Charophyta Family: Desmidiaceae
Cosmarium contractum O. Kirchner 1878
The current status for the Outer Hebrides is unclear as it has spawned many varieties and forms over the years. It would seem to be relatively common in shallow lochans and with submerged Sphagnum and other aquatics. Current critical research into this complex by Kouwets (in manuscript) will help to re-evaluate it.
References:
Kouwets, F.A.C. (in manuscript) European Flora of the Desmid Genus Cosmarium.
West, W. & West, G.S. (1905) A Monograph of the British Desmidiaceae, Volume 2.
Coesel, P.F.M. & Meesters, K.J. (2007) Mesotaeniaceae and Desmidiaceae of the European Lowlands.
John, D.M. & Williamson, D.B. (2009) A Practical Guide to the Desmids of the West of Ireland.