Phylum: Charophyta   Family: Desmidiaceae

Cosmarium subundulatum Wille

Acidophilic from moorland pools and loch margins. Status uncertain but should prove to be not uncommon

References: 
John, D.M. & Williamson, D.B. (2009) A Practical Guide to the Desmids of the West of Ireland
Coesel, P.F.M. & Meesters, K.J. (2007) Mesotaeniaceae and Desmidiaceae of the European Lowlands
West, W. & West, G.S. (1905) A Monograph of the British Desmidiaceae, Volume 2