Phylum: Charophyta   Family: Desmidiaceae

Staurastrum manfeldtii G.B. Delponte 1878

A variable species, which has spawned numerous infraspecific taxon over time. Coesel & Meesters (2013: 116) have made strides to sort the taxonomy but it is probably still ongoing. The main features are rounded base to the semicells, parallel processes and predominantly triradiate.
Overall cell dimensions: L: 31-55 µm; B: 50-85 µm; Is: 8-13 µm; L/B: 0.6-0.7.
Widespread in circumneutral to slightly acidic waters, such as in the plankton of lochs and marginal vegetation of moorland pools.

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