Phylum: Charophyta   Family: Desmidiaceae

Cosmarium pseudosphagnicola F.A.C. Kouwets 2025

There are several similar small cells that display four granules in an asymmetric configuration. They are much confused, and more research is needed to better understand them. It may be possible to separate some of them on habitat preferences.
Cell dimensions: L: 8.1-10 µm; B: 9.4-11 µm; Is: 3.2-4 µm; Th: 4.5-5 µm; L/B: 0.87-0.95.
Found in slightly acidic to mildly alkaline waters. Distribution in the Outer Hebrides unknown due to earlier confusion with similar species.

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