Phylum: Charophyta   Family: Desmidiaceae

Staurastrum cingulum (W. & G.S.West) G.M. Smith 1922

First described and illustrated by West & G.S.West (1903: 548, pl. 18: figs 6-7) as Staurastrum paradoxum var. cingulum. It was later raised by Smith (1922: 353) to species rank. It’s more elongate with longer processes than the variety obesum.
Cell dimensions: L: 50-80 µm; B: 50-85 µm; Is: 9-13 µm.
Much scarcer than the variety obesum and possibly confined to the Atlantic regions. Found in moorland bogs and abandoned peat-cuttings.

References: 
Coesel, P.F.M. & Meesters, K.J. (2013) European Flora of the Desmid Genera Staurastrum and Staurodesmus.
Smith, G.M.(1922) The phytoplankton of the Muskoka region, Ontario, Canada.
West, W. & West, G.S (1903) Scottish freshwater plankton. I.