Revised name: Coniocarpon cinnabarinum
A distinctive species with a light grey or pale orange-brown, and often smooth thallus that may be tinged dull orange in parts and that has a brown prothallus. When present, the apothecia are white to red pruinose and often have bright orange margins. The discs may become purple-brown with age.
Orange areas and apothecia: K+ purple
In Scotland, Arthonia cinnabarina has a scattered and mainly west coast distribution where it grows on the smooth bark of small or young trees such as hazel or on somewhat rougher bark of large trees like beech and ash, in sheltered situations in old woodland. BLS distribution map
scottishlichens.co.uk 