Phylum: Charophyta   Family: Desmidiaceae

Staurodesmus dickiei (J. Ralfs) S. Lillieroth 1950

A small cell with wedge-shaped sinuses, semicells elliptic with a domed apex. Lateral angles support short decumbent spines. Cells are usually triradiate.
Cell dimensions (2): L: 30-32 µm; B: 31-32 µm; Is: 9-9.5 µm; Sp: 4-8 µm; Overall B: 36-41.
Recorded as widespread and locally common in Europe. West, West & Carter (1923: 3, as Staurastrum dickiei) suggest it is generally distributed over Scotland and go on to say: “… is a most ubiquitous Desmid and frequently occurs in great abundance in gatherings from bogs and marshes.” It is proving to be rather scarce in the Outer Hebrides.

References: 
Coesel, P.F.M. & Meesters, K.J. (2013). European Flora of the Desmid Genera Staurastrum and Staurodesmus.
Van Westen, M.C. (2024). Sieralgen in Drenthe.
West, W., West, G.S. & Carter, N. (1923). A Monograph of the British Desmidiaceae, Volume 5.