Thallus: crustose, continuous or rimose-areolate or verrucose-areolate; prothallus: not visible, or white areoles: flat or verrucose or verruculose, thin, opaque, ecorticate surface: yellowish white to yellowish gray or yellowish green, smooth, epruinose, with an indistinct margin, esorediate Apothecia: subimmersed when young, sessile when mature or sessile, 0.3-0.8 mm in diam., lecanorine disc: orange-brown or yellowish brown, plane, epruinose margin: concolorous with thallus, thin or thick, persistent or becoming excluded, even, not flexuose, smooth, entire or verrucose 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-)17-25(-26) µm thick laterally, 10-25 µm thick basally parathecium: hyaline, containing crystals insoluble in K epihymenium: red-brown to orange-brown, with pigment dissolving in K, with crystals dissolving in K hymenium: hyaline, clear; paraphyses: not thickened or slightly thickened (up to 2.5 µm wide) apically, not pigmented; subhymenium: hyaline, 15-20 µm thick; hypothecium: hyaline or pale yellow to yellowish brown, without oil droplets asci: clavate, 8spored ascospores: hyaline, simple, ellipsoid or narrowly ellipsoid, (9-)9.5-13.5(-14) x (5-)6-7(-7.5) µm; wall: less than 1 µm thick Pycnidia: immersed, cerebriform; conidiophores: type II sensu Vobis conidia: filiform, 15-19 µm long Spot tests: thallus and apothecial margin K+ yellow, C-, KC-, P+ pale orange Secondary metabolites: atranorin (major), chloroatranorin (minor), chlorolecideoidin (minor), gangaleoidin (major), leoidin (minor) and norgangaleoidin (minor). Substrate and ecology: on bark of deciduous trees World distribution: pantropical, known from Africa, Asia, Australasia, North and South America, and the Pacific area Sonoran distribution: Sinaloa. Notes: Lecanora leprosa is characterized by its orange to yellowish brown apothecial discs, its granulose epihymenium and the presence of the gangaleoidin chemosyndrome. It is similar to L. achroa and L. helva. The differences are discussed under these species.