Phylum: Charophyta   Family: Desmidiaceae

Actinotaenium cruciferum  (De Bary) Teiling

An acidophile of moorland pools and bogs. Of uncertain status as it's easily confused with similar species

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
Kouwets, F.A.C. (1999) A check-list of desmids (Chlorophyta, Zygnemaphyceae) of France