Family: Teloschistaceae
Caloplaca crenularia (With.) J.R. Laundon
Type: Crustose
On siliceous rocks, in sheltered, often damp situations, also occasionally on walls. The large, brick-red ascomata on a rough greyish thallus are characteristic
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