Phylum: Charophyta Family: Desmidiaceae
Cosmarium contractum var. rotundatum Borge
Widespread, especially in the north-west. An acidophile but tolerant of mildly nutrient rich waters
References:
Coesel, P.F.M. & Meesters, K.J. (2007) Mesotaeniaceae and Desmidiaceae of the European Lowlands
John, D.M., Whitton, B.A. & Brook, A.J. (2011) The Freshwater Algal Flora of the British Isles