A crustose species with a creamy grey to green-grey thallus that is smooth and cracked or slightly warted. Spread out across the thallus are warts with an elliptical base and flat top which may contain one, or sometimes multiple, apothecia.
Thallus: C-, K+ yellow, UV+- pale orange
Pertusaria leioplaca is widespread in Scotland and common on smooth-barked broadleaved trees in shaded situations. BLS distribution map
Pertusaria leioplaca is distinguished from Pertusaria pertusa on basis of the warts being spread out across the thallus rather and the tendency of these warts to contain one apothecium.
scottishlichens.co.uk 