Phylum: Charophyta   Family: Closteriaceae

Closterium juncidum J. Ralfs 1848

Brook & Williamson (2010: 223) comment: “The very great size range of the species should be noted. Other authors have placed the short forms in the var. brevis … and the longest in the var. elongatum …, but a statistical analysis, … indicates that there is no clear dividing line between these and the nominal varieties. For this reason, they have not been recognised in this monograph.” Most current authors still recognise some varieties as the overall size-range of the complex in huge. I have followed this reasoning.
Cell dimensions: L: 200-444 µm; B: 8-11.6 µm; Ap: 4-6 µm; L/B: 20+.
Zygospore diameters: 19-23 µm.
Relatively common in acidic conditions such as Sphagnum bogs.

References: 
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.
Van Westen, M.C. (2024). Sieralgen in Drenthe.