Phylum: Charophyta Family: Desmidiaceae
Staurastrum furcatum Brébisson
An acidophile that is widespread in Europe but not proving common in the Outer Hebrides
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
Prescott, W.G., et al. (2001 reprint) A Synopsis of North American Desmids. Part II, Desmidiaceae: Placodermae, Section 4