Phylum: Charophyta Family: Closteriaceae
Closterium pronum Brébisson 1856
Widespread but not common. Found in acidic peaty pools especially with Sphagnum. It can sometimes be found in 'bundles'.
References:
Brébisson, L. A. de (1856) Liste des Desmidiées, observées en Basse-Normandie.
West, W. & West, G.S. (1904) A Monograph of the British Desmidiaceae, Volume 1.
Brook, A.J. & Williamson, D.B. (2010) A Monograph on some British Desmids.
Coesel, P.F.M. & Meesters, K.J. (2007) Mesotaeniaceae and Desmidiaceae of the European Lowlands.