Phylum: Charophyta   Family: Desmidiaceae

Staurastrum anatinum M.C. Cooke & A.W. Wills 1881

Wills collected extensively in Capel Curig, north Wales, where this taxon was first found. It has a large size-range, which has spawned many varieties. Some of the varieties are quite distinct and may be better raised to species level.
Overall cell dimensions: L: 34-96 µm; B: 48-125 µm; Is: 10-19 µm; L/B: 0.59-0.77.
A widespread species but only common in north Wales, the west of Ireland and north-west Scotland. Found mainly in the plankton of larger lochs, particularly at higher altitudes.

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.