Phylum: Charophyta   Family: Desmidiaceae

Cosmarium pseudo-ornatum B. Eichler & R. Gutwinski 1894

The sinus is slightly dilated at the apex, semicells sub-semicircular, each side of the semicells has 9-10 granules visible, some geminate, the truncate apex is lacking granule. The central protuberance is roughly circular with variable-sized granules.
Cell dimensions: L: 30.8-36.5 µm, B: 30.4-36.2 µm, Is: 10.9-13.6 µm; Th: c.18-20 µm; L/B:1.01-1.06.
An acidophilic desmid found in moorland pools and in the plankton of loch-margins. It would seem to be rare in the British Isles with earlier records from sites in Sutherland, Scotland.

References: 
Kouwets, F.A.C. (2025). European Flora of the Desmid Genus Cosmarium. Part 1: Text. Part 2: Plates.