Family: Lecideaceae
Lecidea phaeops Nyl.
Type: Crustose
Thallus variable in colour from white to greenish, also variable in the amount of crazing. On siliceous rocks with good moisture such as overhangs
References:
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