Phylum: Charophyta   Family: Desmidiaceae

Actinotaenium subtile  (West & G.S.West) Teiling

'This is a rare species which occasionally occurs in prodigious quantity in small pools in the best bogs' - West & West (1904). Specimens occur with either one or two pyrenoids

References: 
West, W. & West, G.S. (1904) A Monograph of the British Desmidiaceae, Volume 1
Coesel, P.F.M. & Meesters, K.J. (2007) Mesotaeniaceae and Desmidiaceae of the European Lowlands
Ruzicka, J. (1981) Die Desmidiaceen Mitteleuropas, Volume 1, Part 2