Phylum: Charophyta   Family: Desmidiaceae

Cosmarium tinctum  Ralfs 1848

Widespread and quite common in acidic bogs and peaty moorland pools.

References: 
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.
John, D.M. & Williamson, D.B. (2009) A Practical Guide to the Desmids of the West of Ireland.