Thallus: crustose, continuous to rimose or verrucose areolate; prothallus: blackish brown or not visible areoles: flat or verruculose, thin, opaque, ecorticate surface: yellowish gray to yellowish white, rough, dull, epruinose, with a distinct margin, esorediate Apothecia: constricted at the base, 0.6-1.6 mm in diam. disc: waxy red to waxy rose or dark red-brown, plane to convex, heavily to sparsely whitish to bluish gray pruinose margin: concolorous with thallus, thick, entire, without a parathecial ring amphithecium: present, with numerous algal cells, with large and small crystals, large crystals insoluble in K, corticate; cortex: hyaline, distinct, gelatinous, interspersed with small crystals, 20-25(-40) µm thick laterally and 75-150 µm thick basally parathecium: hyaline, lacking crystals, epihymenium: dark red-brown to dark brown, with pigment dissolving in K, with coarse crystals dissolving in K, 10-15 µm thick hymenium: hyaline, clear; paraphyses: sparingly branched and thickened (up to 3.5 µm wide) apically; subhymenium: hyaline, 15-20 µm thick; hypothecium: hyaline, without oil droplets asci: clavate, 8-spored ascospores: hyaline, simple, ellipsoid, 9.5-15.5 x 6.5-9 µm Pycnidia: not seen Spot test: thallus and apothecial margin K+ yellow, C-, KC-, P+ yellow Secondary metabolites: atranorin (minor), chloroatranorin (major), and zeorin (major). Substrate and ecology: on bark of trees World distribution: restricted to North America, where it is known from Mexico and southwestern U.S.A. Sonoran distribution: Arizona and southern California. Notes: . Lecanora orizabana is easily recognized by the heavily pruinose apothecial disc, the thick amphithecial cortex, and the absence of depsidones. Most other corticolous L. subfusca-taxa in the Sonoran desert region contain additonal depsidones or chromones, with the exception of L. casuarinophila. This species, however, is readily distinguished by the leprose thallus, a thinner amphithecial cortex, and larger ascospores.