Phylum: Charophyta   Family: Desmidiaceae

Staurodesmus triangularis (Lagerheim) Teiling 1948

Widespread but infrequent in circumneutral waters such as loch-margins and pools. The spines are about two- third or more of the breadth of the cell-body.

References: 
Teiling, E. (1967) The Desmid Genus Staurodesmus. A taxonomic study.
Coesel, P.F.M. & Meesters, K.J. (2013) European Flora of the Desmid Genera Staurastrum and Staurodesmus.
John, D.M. & Williamson, D.B. (2009) A Practical Guide to the Desmids of the West of Ireland.