Phylum: Charophyta Family: Desmidiaceae
Cosmarium dickii Coesel 1989
Once a form of C. blyttii, it was made a species in 1989. The main character is the two supraisthmial granules. It also has a series of intramarginal granules. Found in the tychoplankton of circumneutral waters. Its distribution in the Outer Hebrides is unclear.
References:
Coesel, P.F.M. & Meesters, K.J. (2007) Mesotaeniaceae and Desmidiaceae of the European Lowlands
Kouwets, F.A.C. (in manuscript) European Flora of the Desmid Genus Cosmarium