Phylum: Charophyta   Family: Desmidiaceae

Euastrum biscrobiculatum (Woloszynska) Coesel

A species of slightly acidic habitats, and said to be quite common. However, it can be confused with similar species and its status in the Outer Hebrides in uncertain.

References: 
Coesel, P.F.M. & Meesters, K.J. (2007) Mesotaeniaceae and Desmidiaceae of the European Lowlands