Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.

Thallus: crustose, effuse, granular to verrucose-areolate, sometimes dispersed or reduced to sparse granules near apothecia, prothallus: blackish brown, sparsely developed areoles: thin, opaque, ecorticate surface: yellowish white to whitish gray, smooth, glossy, epruinose, with an indistinct margin, esorediate Apothecia: sessile, 0.3-0.8 mm in diam., biatorine, indistinctly lecanorine when young disc: light brown to dark brown, convex; epruinose to slightly grayish pruinose margin: concolorous with disc, thin, soon becoming excluded, slightly prominent, smooth, entire, without a parathecial ring amphithecium: present, with very sparse algal cells, lacking crystals, ecorticate parathecium: hyaline, lacking crystals epihymenium: brown to reddish brown, with pigment and crystals insoluble in K, with fine crystals insoluble in K hymenium: hyaline, clear; paraphyses: capitate, up to 3 µm thick apically, not pigmented; subhymenium: hyaline, 15-20 µm thick; hypothecium: hyaline, without oil droplets asci: clavate, 8-spored ascospores: hyaline, simple, broadly ellipsoid to subglobose, (4-)4.5-6(-7.5) x (5.5-)8-11(-13) µm; wall: less than 1 µm thick Pycnidia: frequent, immersed, black conidia: filiform, 7-11 x 1-1.5 µm Spot tests: K+ pale yellow, C-, KC-, P+ orange to red Secondary metabolites: confumarprotocetraric acid (trace or absent), fumarprotocetraric acid (major or absent), lobaric acid (major) and unknowns (minor or absent). Substrate and ecology: on bark of conifers or on wood in open pine forests in mountain regions World distribution: circumboreal, occurring in Europe and North America Sonoran distribution: uncertain. Notes: Lecanora fuscescens is a biatorine species that is characterized by broadly ellipsoid ascospores and the presence of fumarprotocetraric and lobaric acids. It may be confused with L. boligera and L. cadubriae, the differences to these species are discussed under these names.