Phylum: Charophyta   Family: Desmidiaceae

Cosmarium fictopyramidatum F.A.C. Kouwets 2025

A recently described species, which was part of the C. pyramidatum Ralfs 1848 complex. It differs in having more rounded semicells and is a little smaller. It needs to be compared with the very similar C. pyramidatiforme Kouwets 2025.
Cell dimensions (4): L: 63.3-75.4 µm; B: 44.2-52.8 µm; Is: 15.1-19.9 µm; Th: 27-30.5 µm; L/B: 1.43-1.47.
Because of the earlier confusion with similar species, the status in the Outer Hebrides is uncertain. It prefers acidic, meso-oligotrophic, moorland pools and bogs.

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