Closterium ralfsii var. hybridum

References

Brook, A.J. and Williamson D.B. (2010). A Monograph on Some British Desmids. pp. 298-299. London: The Ray Society.

Brook, A. J., John, D. M. and Whitton, B.A., et al. (2017). The freshwater algal flora of the British Isles: an identification guide to freshwater and terrestrial algae. 2nd edition. pp. 621, 631. Cambridge: Cambridge University Press.