Phylum: Charophyta Family: Desmidiaceae
Xanthidium armatum Brébisson ex Ralfs
One of the larger desmids frequently encountered in Sphagnum bogs and moorland peaty pools
References:
West, W. & West, G.S. (1912) A Monograph of the British Desmidiaceae, Volume 4
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