Phylum: Glaucophyta   Family: Glaucocystaceae

Glaucocystis nostochinearum  Itzigsohn

A transitory phylum between cyanobacteria and algae. This species is reported as widespread in acidic weedy margins

References: 
John, D.M., Whitton, B.A. & Brook, A.J. (2011 second edition) The Freshwater Algal Flora of the British Isles