A foliose species with a dark brown thallus that consists of lobes that are consistently overlapping and markedly crowded. The margins are often upturned. The upper surface of the lobes is smooth and has faint, white, linear pseudocyphellae scattered across them.
Medulla: C-, K-, UV+ faintly glaucous white
In Scotland, Parmelia discordans occurs mainly in upland regions where it is found on nutrient-poor, but well-lit, siliceous rocks. BLS distribution map
Parmelia discordans is distinguished from Parmelia omphalodes on basis of the presence of a clear network of pale lines that are not raised.
scottishlichens.co.uk 