Graphis scripta (L.) Ach.
Common Script Lichen
Very common on smooth-barked trees and particularly noted on heather stems. Elongated, curved or branched apothecia with raised, smooth margins
Smith, C.W. et al. editors (2009) The Lichens of Great Britain and Irelandd
Dobson, F.S. (2018) Lichens: an Illustrated Guide to the British and Irish Species