Phylum: Charophyta Family: Desmidiaceae
Staurastrum pachyrhynchum Nordstedt
An Arctic/boreal species of acidic conditions. Status unknown in the Outer Hebrides
References:
Coesel, P.F.M. & Meesters, K.J. (2013) European Flora of the Desmid Genera Staurastrum and Staurodesmus
Prescott, W.G., et al. (2001 reprint) A Synopsis of North American Desmids. Part II, Desmidiaceae: Placodermae, Section 4