Phylum: Charophyta Family: Desmidiaceae
Cosmarium quadrum P. Lundell
Acidic to circumneutral waters: pools, cuttings and ditches. Infrequently recorded. West & West (1912) note "… the rarest of the conspersum-group in the British Isles, …"
References:
West, W. & West, G.S. (1912) A Monograph of the British Desmidiaceae, Volume 4
John, D.M. & Williamson, D.B. (2009) A Practical Guide to the Desmids of the West of Ireland
Coesel, P.F.M. & Meesters, K.J. (2013) European Flora of the Desmid Genera Staurastrum and Staurodesmus