Phylum: Charophyta Family: Desmidiacea
Staurastrum pingue Teiling
Thought to be fairly common in slightly alkaline waters, especially with plankton. Easily confused with similar species
References:
Coesel, P.F.M. & Meesters, K.J. (2013) European Flora of the Desmid Genera Staurastrum and Staurodesmus