Phylum: Charophyta   Family: Closteriaceae

Closterium angustatum Kützing ex Ralfs 1848

A widespread and locally common species found in acidic habitats such as peat bogs. It is frequently found with Sphagnum. The specific epithet means 'narrowed' referring to the pinched sub-apices.

References: 
Ralfs, J. (1848) The British Desmidieae.
West, W. & West, G.S. (1904) A Monograph of the British Desmidiaceae, Volume 1.
Brook, A.J. & Williamson, D.B. (2010) A Monograph on some British Desmids.
Coesel, P.F.M. & Meesters, K.J. (2007) Mesotaeniaceae and Desmidiaceae of the European Lowlands.