Usnea cornuta Körb.
Found on mossy, usually broad-leaved woodland or wayside trees, more rarely siliceous rocks. A very variable, widespread occurring in two equally frequent and widespread chemical races. The shrubby habit and widely divergent branching pattern is characteristic.
Smith et al. editors (2009) The Lichens of Great Britain and Ireland
Dobson (2018) Lichens: an Illustrated Guide to the British and Irish Species
Thell & Moberg, editors (2011) Nordic Lichen Flora, Volume 4: Parmeliaceae