Phylum: Charophyta   Family: Desmidiaceae

Cosmocladium constrictum (W. Archer) W. Joshua 1883

First described by Archer (1867: 299) as Dictyosphaerium constrictum. Later moved to Cosmocladium by Joshua (1883: 292). Cells subcylindrical with a widely open sinus. Apical view almost cylindrical.
Cell dimensions: L: 13-18 µm; B: 8-12 µm.
Found in mesotrophic habitats but rarely recorded.

References: 
Archer, W. in: Lankester, E. & Busk, G. (Editors) (1867) Proceedings of Societies. Quarterly journal of microscopical science.
Coesel, P.F.M. & Meesters, K.J. (2023 second edition) Desmids of the Lowlands.
Joshua, W. (1883). Notes on British Desmidieae. II.
Prescott, W.G. et al. (2001 reprint) A Synopsis of North American Desmids. Part II, Desmidiaceae: Placodermae, Section 3.
West, W., West, G.S. & Carter, N. (1923) A Monograph of the British Desmidiaceae, Volume 5.