Phylum: Charophyta   Family: Desmidaceae

Closterium jenneri Ralfs 1848

Much has been written regarding the similarities with Cl. cynthia. The latter supporting girdle-bands and striae, while Cl. jenneri is lacking (although some authors suggest faint striae are sometime noted). Cl. cynthia is common in acidic habitats whereas Cl. jenneri is proving to be rather scarce in the Outer Hebrides. There is also the possibility that it occupies a different habitat as the few finds so far are from circumneutral and slightly alkaline waters.

References: 
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.