Phylum: Charophyta Family: Desmidiaceae
Staurodesmus megacanthus var. scoticus (West & G.S. West) S. Lillieroth
A planktonic species of the north-west in particular. Thought probably common but little data available. John & Williamson (2009) indicate more divergent spines than Coesel & Meesters (2013)
References:
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