Phylum: Charophyta   Family: Desmidiaceae

Actinotaenium silvae-nigrae  (Rabanus) Kouwets & Coesel

An oligotrophic species which is proving to be quite common in moorland pools and disused peat-cuttings. Earlier references will have this under the Penium genus

References: 
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
John, D.M. & Williamson, D.B. (2009) A Practical Guide to the Desmids of the West of Ireland