Graphis elegans (Borrer ex Sm.) Ach.
Smooth, greyish thallus, lirellate apothecia with raised carbonaceous furrowed margins. Found on smooth barked trees and twigs
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