Phylum: Charophyta   Family: Mesotaeniaceae

Roya obtusa (L.A. de Brébisson) W. West & G.S. West 1896

First described and illustrated by Brébisson (1856: 154, pl. 2: 4) as Closterium obtusum. It was later moved to Roya by West & West (1896: 107, pl. 10: 27). Coesel & Meesters (2023: 26) note: “Cells more or less cylindrical, slightly curved, 5-15 times longer than broad. Apices obtusely rounded.”
Cell dimensions: L: 35-150 µm; B: 5-15 µm; L/B: 5-15.
Infrequently recorded. Found in acidic habitats such as moorland pools and bogs.

References: 
De Brébisson, L.A. (1856). Liste des Desmidiées, observées en Basse-Normandie.
Coesel, P.F.M. & Meesters, K.J. (2023 second edition). Desmids of the Lowlands.
West, W. & West, G.S. (1896). On some new and interesting freshwater algae.