Thallus: crustose, continuous or verrucose-areolate or dispersed-areolate; prothallus: not visible areoles: flat or verrucose or verruculose, thin or thick, opaque, ecorticate surface: yellowish white to yellowish gray or whitish gray to gray, smooth or rough, epruinose, with an indistinct margin, esorediate Apothecia: sessile or adnate or constricted at the base to almost subpedicilate, 0.5-1.5 mm in diam., lecanorine disc: red-brown or yellowish brown or dark brown to blackish brown or gray-brown, plane, slightly whitish gray pruinose margin: concolorous with thallus, thick, persistent, even or prominent, 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: present, hyaline or pale yellow, distinct, basally thickened, gelatinous or interspersed, (10-)15-20(-30) µm thick laterally, 25-60 µm thick basally parathecium: hyaline, lacking crystals epihymenium: red-brown to orange-brown or brown to dark brown, with pigment dissolving in K, with crystals dissolving in K hymenium: clear; paraphyses: slightly thickened (up to 3 µm wide) apically, not pigmented; subhymenium: hyaline, 15-20 µm thick; hypothecium: hyaline, without oil droplets asci: clavate, 8-spored ascospores: hyaline, simple, broadly ellipsoid, 9.5-17.5 x (6-)6.5-8(-9) µm; wall: more than 1 µm thick Pycnidia: not seen Spot tests: K+ yellow, C-, KC-, P- or P+ pale yellow Secondary metabolites: atranorin (major), chloroatranorin (minor), and roccellic acid (major or absent). Substrate and ecology: usually on siliceous rocks across a wide range of habitats, or less frequently on wood World distribution: temperate Holartic known from northern Africa, Asia, Europe, and North America Sonoran distribution: Arizona, California, Baja California Sur, and Chihuahua. Note: Lecanora cenisia is one of the more common Lecanoras on rocks in montane areas. It is characterized by brown to black, slightly pruinose apothecial discs, a granulose epihymenium, and large amphithecial crystals. It is a very variable species regarding the color of the apothecial disc and the chemistry (Brodo 1984). Lecanora campestris can be similar, but is readily distinguished by a egranulose epihymenium and the small amphithecial crystals.