Phylum: Charophyta   Family: Closteriaceae

Closterium cynthia G. De Notaris 1867

First described and illustrated by De Notaris (1867: 65, fig. 71; pl. 7). Almost identical to C. jenneri in outline but that species has no striae or girdle bands.
Cell dimensions: L: 90-156 µm; B: 12.2-16.6 µm; Ap: 3.2-5 µm; Arc: 123-162°; L/B: 7-10.
Zygospore diameter: 32-35 µm.
The species is widespread and common in association with peaty pools and loch-margins.

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.
De Notaris, G. (1867). Elementi per lo studio delle Desmidacee Italiche. Desmidacée delle Val Itrasca.
West, W. & West, G.S. (1904). A Monograph of the British Desmidiaceae, Volume 1.