Thallus: continuous to fissured or fissured-areolate, with moderately thick verrucae; margins: entire, unzoned upper surface: ash gray to greenish gray, smooth or rugose-plicate, shiny, epruinose; lacking soredia or isidia fertile verrucae: concolorous with thallus, lecanorate, numerous, often fused, c. 0.4-1.2 mm in diam. Apothecia: 1 (-5) per verruca; disc: blackish brown, well sunken, epruinose or grayish pruinose, margins crenulate; epithecium: dark brown, K+; hypothecium: hyaline asci: clavate or cylindrical, 150-250 x 45-70 µm, (1-) 2-spored ascospores: hyaline, oval to ellipsoid, 50-140 x 26-58 µm; spore wall: c. 4-14 µm thick, smooth; apices: up to 18 µm thick, 1-layered Pycnidia: not seen Spot tests: K-, C-, KC-, P-, UV- Secondary metabolites: 2-O-methylconfluentic acid (major), di-O-methylolivetoride, planaic acid and traces of unknowns (all minor). Substrate and ecology: on conifers (e.g. Juniperus) and more common on wood World distribution: endemic to North America, particularly at mid-elevations in the Rocky Mountain region Sonoran distribution: mountainous areas of Arizona at 1700-2100 m. Notes: Pertusaria saximontana is characterized by a shiny gray to gray-brown thallus, numerous disciform apothecia with blackish, epruinose discs, a K+ violet epithecium, 2-spored asci, and the presence of 2-O-methylconfluentic acid. It is is a very characteristic species and hardly confused with any other Pertusaria species occurring in southwestern North America.