Phylum: Charophyta   Family: Desmidiaceae

Cosmarium crenulatum C. Nägeli 1849

This taxon is thought to be widespread in a range of habitats from mesotrophic to more acidic peaty pools. It is readily confused with similar species, and we await more taxonomic clarification.
Cell dimensions: L. 24-33 µm; B. 18-24 µm; Is. 6-8 µm; Th. 9-12 µm; L/B. 1.3-1.45.

References: 
Coesel, P.F.M. & Meesters, K.J. (2023 second edition). Desmids of the Lowlands.
Kouwets, F.A.C. (in manuscript). European Flora of the Desmid Genus Cosmarium.
Nägeli, C. (1849). Gattungen einzelliger Algen, physiologisch und systematisch bearbeitet.
Van Westen, M. (2024). Sieralgen in Drenthe.