Phylum: Charophyta   Family: Closteriaceae

Closterium turgidum Ehrenberg ex Ralfs

A large cell found mainly in acidic moorland pools and bogs, especially with Sphagnum. Said to be widespread in suitable habitats but proving to be quite scarce in the Outer Hebrides

References: 
Brook, A.J. & Williamson, D.B. (2010) A Monograph on some British Desmids
John, D.M. & Williamson, D.B. (2009) A Practical Guide to the Desmids of the West of Ireland
Coesel, P.F.M. & Meesters, K.J. (2007) Mesotaeniaceae and Desmidiaceae of the European Lowlands