Description

 Mycelium: I-; Apothecia: superficial to substipitate, (100-)150-250(-350) µm in diam.; disc: black, not or scarcely pruinose, from the beginning strongly convex; hymenium: pale brown, K+ green in the upper part, K- in the lower part; hypothecium: dark reddish brown, K- (or pale yellow); asci: elongate ellipsoid to clavate, 8-spored; ascospores: olivaceous when young, becoming brown, verrucose, 1-sepate, cells slightly unequal, (10.5-)12-14.5(-16.5) x (4.5-)5.5-6.5(-7) µm; Pycnidia: not known with certainty.; Hosts: thallus of Hypogymnia and Cavernularia species; in the Sonoran area on C. lophyrea; World distribution: Europe and North America; Sonoran distribution: once collected in California.; Notes: Abrothallus prodiens was described from Hypogymnia, and later also reported from the related genus Cavernularia. The species is very close to A. parmeliarum, from which it appears to be distinguished by generally smaller and often substipitate apothecia.