Phylum: Charophyta   Family: Closteriaceae

Closterium ehrenbergii Meneghini ex Ralfs 1848

The largest British species in the genus and extremely variable: size can be less than 250 to over 1000 µm; apices can be narrowly rounded to broadly rounded; habitat is mixed hence also the pH - either side of neutral. Modern authors regard it as a species-complex.

References: 
Ralfs, J. (1848) The British Desmidieae.
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.