Phylum: Charophyta   Family: Desmidiaceae

Cosmarium beanlandii F.A.C. Kouwets 2025

This recently renamed taxon is quite distinct and not easy to confuse with other species, even though it has a complicated taxonomy. See Kouwets (2025) for more details. A large cell with a closed sinus for the most part. Semicells are depressed pyramidate with about 11 undulations along each side of the semicell, which continue across the later sides but not the face. The cell-wall is smooth with fine pores.
Cell dimensions: L: 80-86 µm; B: 55-60 µm; Is: 21-23 µm; Th: c.34 µm; L/B: 1.40-1.50.
A rare desmid found in Ireland and the Outer Hebrides. More finds are needed to get a better geographical perspective but the Atlantic north-west may be its stronghold. The preferred habitat is oligotrophic moorland pools and bogs, usually with Sphagnum.

References: 
John, D.M. & Williamson, D.B. (2009). A Practical Guide to the Desmids of the West of Ireland.
KoKouwets, F.A.C. (2025). European Flora of the Desmid Genus Cosmarium. Part 1: Text. Part 2: Plates.