Phylum: Charopyta Family: Mesotaeniacea
Netrium naegelii (Brébisson ex W. Archer) West
Similar to Netrium digitus but smaller and with only two, phragmented, chloroplast ridges. These tend to bifurcate as they reach the cell wall (see the upper image in Plate 1). Found in moorland pools and Sphagnum bogs, it's distribution is Atlantic but proving elusive in the Outer Hebrides
References:
West, W. & West, G.S. (1904) A Monograph of the British Desmidiaceae, Volume 1
Brook, A.J. & Williamson, D.B. (2010) A Monograph on some British Desmids