Phylum: Chrophyta Family: Desmidiaceae
Cosmarium sp. (5)
This cell is rather similar to the recently described Cosmarium neocrenatum by Van Westen & Coesel (2021). That species is slightly smaller so it's probably not justified in attaching this cell to that species. More finds are necessary, especially displaying intermediate sizes. Frans Kouwets drew my attention to a figure of C. saxicolum in Grönblad (1963, p. 26, Pl. 4: 30) collected from moist mosses on a rock in Norway, near the Swedish border. However, he went on to note: "C. saxicola is a problematic form and Grönblad’s drawing most probably shows another, unknown and possibly undescribed species. Grönblad (1933) presented a similar form and suggested that it might rather be a form of C. crenatum. In my opinion C. crenatum is just another problematic species and I don't share his opinion."
Van Westen, M. & Coesel, P.F.M. (2021) Taxonomic notes on desmids from the Netherlands IV, with a description of another five new species
Grönblad, R. (1963) Desmids from Jämtland, Sweden and adjacent Norway