Protoparmelia montagnei  

Like Protoparmelia badia, but the thallus is usually paler with numerous pycnidia and often delimited (especially when young).  Best distinguished by its cylindric-ellipsoidal ascospores 9-13 × 2-3.5 (-4.5) μm in size, and by chemistry. There are three chemotypes (reactions are for upper medulla and cortex in sections): (1) gyrophoric and lobaric acids, C+ red, UV+ white; (2)  lobaric acid, C–, KC+ reddish, UV+ white; (3) gyrophoric acid, C+ red, UV–; all chemotypes have traces of unidentified substances (but different from those in P. badia). It should be noted that reactions of the lower part of the thallus can be unreliable as this tissue often belongs to another species overgrown by P. montagnei. Singh et al. (2015) found some correlation between chemotype and phylogeny, and suggested that these may represent cryptic species.