Phylum: Charophyta Family: Desmidiaceae
Cosmarium reniforme var. compressum Nordstedt
A depressed shape of the nominate variety occupying the same habitat requirements. However, it would appear to be less common
References:
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. (1908) A Monograph of the British Desmidiaceae, Volume 3