Thallus: crustose, verruculose or verrucose areolate; prothallus: white areoles: verrucose or verruculose, thick, opaque, ecorticate surface: smooth, grayish white to greenish white, epruinose; with an distinct margin, esorediate Apothecia: sessile, 0.5-1.2 mm in diam., lecanorine disc: orange-brown or yellowish brown, plane, slightly whitish gray pruinose margin: concolorous with thallus, thick, persistent, slightly prominent, flexuose, smooth, entire or verruculose, without a parathecial ring amphithecium: present, with numerous algal cells, with large crystals insoluble in K, corticate; cortex: hyaline, indistinct, basally not thickened, interspersed, 10-33 µm thick parathecium: hyaline, containing crystals insoluble in K epihymenium: dark brown to brownish orange, with pigment dissolving in K, with crystals dissolving in K hymenium: hyaline, clear; paraphyses: not thickened apically, not pigmented; hypothecium: hyaline, without oil droplets asci: clavate, 8-spored ascospores: hyaline, simple, broadly ellipsoid, 7-10 x (4.5-)5.5-6.5(-7) µm; wall: less than 1 µm thick Pycnidia: not seen Spot test: thallus and apothecial margin K+ yellow, C-, KC-, P+ pale orange Secondary metabolites: containing atranorin (major), chloroatranorin (minor), 2'-O-methylperlatolic acid (major) and 2'-O-methylstenosporic acid (minor). Substrate and ecology: on exposed siliceous rocks World and Sonoran distribution: endemic to the Sonoran Desert region in Sonora. Notes: Lecanora neosonorensis is characterized by the slightly pruinose apothecial disc, the presence of 2'-Omethylperlatolic acid and the small, broadly ellipsoid ascospores. Lecanora plumosa is similar, but readily distinguished by the epruinose disc, slightly larger and less broad ascospores, and a different epihymenial color. Further, the minor constituents in the two species differ. Another similar species is L. pseudistera, which differs in having a red-brown, egranulose epihymenium.