Phylum: Chlorophyta Family: Cladophoraceae
Cladophora glomerata (Linnaeus) Kützing
This is one of the commonest algae. Found attached to a rocks and other firm substrates. In favourable habitat, it can form extensive mats
References:
John, D.M., Whitton, B.A. & Brook, A.J. (2011) - The Freshwater Algal Flora of the British Isles