Phylum: Charophyta   Family: Closteriaceae

Closterium kuetzingii  L.A. de Brébisson 1856

First described and illustrated by Brébisson (1856: 156, pl. 2: 40). Very similar to Closterium setaceum although that species tends to be slenderer and has fewer pyrenoids.
Cell dimensions: L: 260-550 µm; B: 14-27 µm; Ap: 2.8-3.9 µm; L/B: (10-)15-33.
Zygospore: 49-56 x 37-40 µm.
A common species of mainly acidic waters where it can be found in marginal vegetation and also with Sphagnum.

References: 
De Brébisson, L.A. (1856). Liste des Desmidiées, observées en Basse-Normandie.
Brook, A.J. & Williamson, D.B. (2010). A Monograph on some British Desmids.
Coesel, P.F.M. & Meesters, K.J. (2023 second edition). Desmids of the Lowlands.
Ralfs, J. (1848). The British Desmidieae.