Phylum: Charophyta   Family: Desmidiaceae

Staurastrum margaritaceum J. Ralfs 1848

There is little to confuse this species with. Most specimens are 3-4-radiate but occasionally up to 6-radiate. The 6-radiate cells need to be compared with Staurastrum sexcostatum, which is similar but more ornate and slightly larger.
Cell dimensions: L: 23-35 µm; B: 21-28 µm; Is: 7-11.5 µm.
A very common acidophile found in Sphagnum bogs and moorland pools.

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.