Widespread on rocky coastal habitats but not common. Found on the tops of rocks that have been nutrient-enriched, usually by birds. Distinctive coarsely warted thallus, often indistinctly lobed, and with apothecia on stalks

Determiner: 
Chris Johnson

References: 
Smith et al. editors (2009) The Lichens of Great Britain and Ireland
Dobson (2018) Lichens: an Illustrated Guide to the British and Irish Species