Phylum: Charophyta   Family: Closteriaceae

Closterium acutum J. Ralfs 1848

First described by Ralfs (1848: 177, pl. 30: 5a-f; pl. 25: 5) and illustrated mainly by Jenner. Similar to Closterium cornu but that species is more robust.
Cell dimensions: L: 90-130 µm; B: 4-6 µm; Ap: 1.5-2.4 µm; L/B: 14-25.
A relatively common acidophile found in moorland pool and peat bogs, especially with Sphagnum.

References: 
Brook, A.J. & Williamson, D.B. (2010). A Monograph on some British Desmids.
Coesel, P.F.M. & Meesters, K.J. (2013). European Flora of the Desmid Genera Staurastrum and Staurodesmus.
Ralfs, J. (1848). The British Desmidieae.