A crustose species with a white to pale grey, smooth to cracked thallus that occasionally is surrounded by a black prothallus. The relatively large apothecia have an orange-brown to dark brown discs that may be pruinose when young. The thalline margin is distinctively inflated and pruinose.
Thallus: C-, K+ yellow, UV+ pale orange
In Scotland, Lecanora intumescens is found mainly in the central and western Highlands where it grows on smooth-barked, deciduous trees in woodlands and along roads. BLS distribution map
scottishlichens.co.uk 