Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Thallus: crustose, continuous or rimose-areolate or verrucose-areolate; prothallus: not visible, or white areoles: flat or verrucose or verruculose, thin or thick, opaque, ecorticate surface: whitish gray to gray or white to cream-colored, smooth, slightly pruinose or white pruinose, with an indistinct margin, esorediate Apothecia: sessile or adnate, 0.3-2 mm in diam., lecanorine disc: pale pink to carneous, plane or convex, heavily whitish gray pruinose margin: concolorous with thallus, thin or thick, persistent, prominent, entire or flexuose, smooth, entire, without a parathecial ring amphithecium: present, with numerous algal cells, with numerous small crystals which dissolve in K, corticate; cortex: absent or indistinct and hyaline, basally not thickened, interspersed, (23-)25-30(-35) µm thick laterally, (23-)25-35(-40) µm thick basally parathecium: hyaline, containing crystals soluble in K epihymenium: brown to dark brown, with pigment dissolving in K, with crystals dissolving in K hymenium: hyaline, 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, (12-)13.5-15(-16) x (7-)9-11(-12) µm Pycnidia: not seen Spot tests: thallus and apothecial margin K+ yellow or yellow turning red, C-, KC-, P+ yellow or red or P+ orange to red Secondary metabolites: atranorin (major), chloroatranorin (minor), connorstictic acid (minor or absent), norstictic acid (major or absent), protocetraric acid (major or absent), and salazinic acid (minor or absent). Substrate and ecology: on exposed siliceous rocks, rarely on bark (no corticolous Sonoran specimen seen) World distribution: a pantropical species, extending towards the subtropics and temperate regions in the Southern Hemisphere, also from Africa, Australasia, North and South America Sonoran distribution: Chihuahua. Notes: Lecanora farinacea is notorously variable, and is characterized by the whitish gray to gray thallus, the presence of the norstictic acid chemosyndrome in addition to protocetraric acid and the relatively large spores. It can be distinguished from other similar species by the presence of an amphithecial cortex with small crystals that are insoluble in K.