Phylum: Charophyta   Family: Mesotaeniaceae

Roya obtusa var. montana W. & G.S. West 1896

An infrequently recorded species, found in oligo-mesotrophic acidic waters such as loch-margins and moorland pools.
Cell dimensions: L: 39-90 µm; B: 6.4-6.7 µm; L/B: 6-14 µm.
It differs from the nominate variety in having more truncate apices, which can be slightly pinched.

References: 
Coesel, P.F.M. & Meesters, K.J. (2023 second edition). Desmids of the Lowlands.
Van Westen, M.C. (2024). Sieralgen in Drenthe.