Phylum: Charophyta   Family: Desmidiaceae

Cosmarium sphagnicoliforme M.C. van Westen & P.F.M. Coesel 2021

A very small cell with the sinuses V-shaped with a rounded apex. Semicells are rounded oblong-rectangular, lateral sides evenly rounded with small asymmetrical granule usually present, Apices truncate to slightly depressed. Chloroplast is axile with a single pyrenoid.
Cell dimensions (3): L: 8.6-9.6 µm, B: 9-10.8 µm, Is: 2.8-3 µm; Th: c.5-6 µm; L/B: 0.89-0.96.
Found in acidic, boggy habitats, often with Sphagnum. Only one site has been identified so far (2025) in the Outer Hebrides.

References: 
Kouwets, F.A.C. (2025). European Flora of the Desmid Genus Cosmarium. Part 1: Text. Part 2: Plates.
Van Westen, M.C. (2024). Sieralgen in Drenthe.