Phylum: Charophyta   Family: Desmidiaceae

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

First described by Cooke & Wills (1881: 92) and illustrated by Cooke (1880: 139: 6). Wills collected extensively in Capel Curig, north Wales, where this taxon was first found. It has a large size-range, which may represent more than one taxon.
Cell dimensions: L: 47-73 µm; B: 74-102 µm; Is: 13-17 µm.
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: 
Cooke, M.C. (1881) Notes on British desmids.
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.