Phylum: Charophyta   Family: Desmidiaceae

Staurastrum manfeldtii Delponte 1878

A variable species which is widespread in circumneutral to slightly acidic waters, such as in the plankton of lochs and marginal vegetation of moorland pools

References: 
John, D.M. & Williamson, D.B. (2009) A Practical Guide to the Desmids of the West of Ireland
Coesel, P.F.M. & Meesters, K.J. (2007) Mesotaeniaceae and Desmidiaceae of the European Lowlands