A foliose lichen that is instantly recognisable because of the texture of the upper surface of its strap-shaped branches that is densely covered with isidia and/or small lobules. The margins of the grey lobes curl under, and the under surface is black.
Cortex: K+ yellow. Medulla: C- or C+ rose-red, K-, UV-
In Scotland, Pseudevernia furfuracea is common on acid-barked trees and fences in upland areas. It can also be found on well-lit siliceous rocks, including gravestones. BLS distribution map
Pseudevernia furfuracea is easily distinguished from Evernia prunastri by the presence of isidia rather than soredia, and by the under surface of the lobes at least being black in part.
scottishlichens.co.uk 