Mycelium: I- Apothecia: superficial, (100-)150400(-550) µm in diam. disc: black, often covered by a green pruina, from the beginning strongly convex epihymenium: dark olivaceous brown, K+ green, with a crystalline layer that is K+ yellow, dissolving in K hymenium: hyaline to greenish, K-, 50-80 µm hypothecium: dark reddish brown, K- asci: elongate ellipsoid to clavate, 8spored ascospores: dark brown, verrucose, 1-septate, cells unequal in width, 11.5-16(-17.5) x 4.5-7 µm Pycnidia: black, sometimes with a green pruina, partly immersed or superficial; wall: reddish brown, in upper part dark brown, K-; conidiogenous cells: 8-12 x 3-4 µm conidia: hyaline, obpyriform, surface finely verruculose, often appearing as smooth, 7.5-10 x 5.5-7 µm. Hosts: thallus and apothecia of Parmelia s. str. species; also reported from a number of other parmelioid genera, but identity of those specimens has to be re-checked; in the Sonoran area on Parmelia sulcata World distribution: known from all continents except Antarctica Sonoran distribution: Once collected in Arizona. Notes: Abrothallus parmeliarum is a relatively common and widespread fungus on Parmelia s. str., often growing over galls induced by Phacopsis oxyspora. Vouauxiomyces santessonii D. Hawksw. was described as its anamorph. However, the type of V. santessonii grows on Platismatia, and it is not sure if the Abrothallus confined to this host (often called Abrothallus cetrariae Kotte) is conspecific with A. parmeliarum.