Phylum: Charophyta   Family: Closteriaceae

Closterium upsaliense P.F.M. Coesel & K.J. Meesters 2023

This was originally described by Nordstedt (1889: 47) as Closterium cornu var. upsaliense. Very recently, Coesel & Meesters raised it to species level base on the horned zygospores, which differ from those described for var. upsaliense, as depicted by Ruzicka (1977, pl. 8:7). This newly formed species is also a little smaller than C. cornu.
Cell dimensions: L: 40-60(-85) µm; B: 5-7 µm; L/B: 10-12.
It would seem to be a rare desmid. Found in acidic habitats such as moorland pools and bogs.

References: 
Coesel, P.F.M. & Meesters, K.J. (2023 second edition) Desmids of the Lowlands.
Ruzicka, J. (1977) Die Desmidiaceen Mitteleuropas, Volume 1, Part 1.
Nordstedt, C.F.O. in Wittrock, V.B., Nordstedt, C.F.O. & Lagerheim, G. (1889) Algae aquae dulcis exsiccatae praecipue scandinavicae quas adjectis algis marinis chlorophyllaceis et phycochromaceis. Vol. Fasc. 20