Phylum: Charophyta   Family: Desmidiaceae

Staurastrum controversum L.A. de Brébisson ex J. Ralfs 1848

First described by Brébisson in Ralfs and illustrated by Jenner (1848: 141, pl. 23: 3 a-h). Occurs in tri- and quadri-radiate forms.
Cell dimensions: L. 25-45 µm, B. 33-55 µm, Is. 7-12 µm.
Found in the margins of shallow lochs. It was generally recorded in the Wests' (1923: 162) time but now possibly rare.

References: 
Coesel, P.F.M. & Meesters, K.J. (2013). European Flora of the Desmid Genera Staurastrum and Staurodesmus.
Ralfs, J. (1848). The British Desmidieae.
West, W., West, G.S. & Carter, N. (1923). A Monograph of the British Desmidiaceae, Volume 5.