Phylum: Charophyta   Family: Desmidiaceae

Cosmarium impressuliforme F.A.C. Kouwets 2025

A much-confused group of desmids based on the poorly described Cosmarium impressulum Elfving 1881. See Kouwets (2025) for a detailed analysis.
Kouwets’ cell dimensions: L. 19-25 µm; B. 14-17.5 µm; Is. 4.5-7 µm; Th. 9-12 µm; L/B. 1.23-1.54.
Found in acidic to mildly alkaline waters such as moorland pools, loch-margins and disused peat-cuttings.

References: 
Kouwets, F.A.C. (2025). European Flora of the Desmid Genus Cosmarium.