Phylum: Charophyta   Family: Desmidiaceae

Cosmarium reniforme (elevated form) (Ralfs) W. Archer 1874

This form has markedly raised apices, possibly first described by Zwart (1969, p. 169, figs 74-75). It is distinctly different from the nominate prompting Kouwets (in manuscript) to raise it to species rank. The proposed name is Cosmarium alteroreniforme. Of the few records currently known, it would seem to enjoy neutral to slightly alkaline mesotrophic waters.

References: 
Zwart, K.W.R. (1969) Het voorkomen van Desmidiaceae in de Molenpolder 1961-1962.
Kouwets, F.A.C. (in manuscript) European Flora of the Desmid Genus Cosmarium.