Phylum: Charophyta   Family: Desmidiaceae

Actinotaenium diplosporum f. minus  (Cushman) Teiling

Differs from the nominate in its smaller size. It would appear to be scarcer. An acidophile of moorland bogs

References: 
Coesel, P.F.M. & Meesters, K.J. (2007) Mesotaeniaceae and Desmidiaceae of the European Lowlands