Phylum: Charophyta Family: Desmidiaceae
Cosmarium impressulum var. crenulatum (Nägeli) Willi Krieger & Gerloff 1965
A northern species, mostly found in the north-west of Scotland in peaty pools, especially with Sphagnum.
References:
Krieger, W. & Gerloff, J. (1962-9) Die Gattung Cosmarium.
Coesel, P.F.M. & Meesters, K.J. (2007) Mesotaeniaceae and Desmidiaceae of the European Lowlands.
John, D.M. & Williamson, D.B. (2009) A Practical Guide to the Desmids of the West of Ireland.
West, W. & West, G.S. (1905) A Monograph of the British Desmidiaceae, Volume 2.