Phylum: Charophyta   Family: Desmidiaceae

Staurastrum lapponicum (Schmidle) R. Grönblad 1926

The size of the granules can vary between populations; it lacks supraisthmial granules found in similar species.
Cell dimensions: L: 30-44 µm; B: 30-42 µm; Is: 8.2-9.6 µm.
An acidophile, rather common in the phytoplankton.

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.