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

Thallus: crustose, central part areolate; the marginal areoles usually elongate and distinctly radiate, bordered by a distinct black prothallus areoles: sharply angular, 0.30.5(-1) mm broad, flat or +convex, upper surface: pale yellow to usually coppery brown or sometimes gray-black or brownish black, the outer areolae paler, shiny or dull, cortex: pale gray below and pale brown above, 35-85 µm thick, covered by a thick necral layer, composed of dense hyphae with irregular cells 3-6 x 1 µm medulla: white to gray, composed of interwoven pachydermatous hyphae inspersed with granules; algal layer: +evenly distributed lower surface: black, visible as a border around the areoles Apothecia: common, initiated in the areolae but soon displacing the areolae and appearing among the areolae, immersed and level with the surface of the thallus, up to 1 mm wide disc: black, smooth or with numerous punctate fissures margin: black, thin exciple: dark brown, 20-50 µm thick, lower part sometimes pale hymenium: hyaline below, the upper 20-30 µm dark or blackish green, 85-120 µm tall, I+ dark blue, K+ blue-green or the upper part initially red-violet, N+ violet-red; paraphyses: with little gelatin, 1.7-2 µm wide below; tips: 2.5-3.5 µm wide, pale brown or pale violet; hypothecium: light gray or purplish brown to yellow-brown, 35-100 µm thick, I+ dark blue asci: broadly clavate, 60-65 x 17-22 µm; 100+-spored ascospores: broadly ellipsoid or spherical, 3-4 x 2-3 µm Pycnidia: immersed conidia: 3-4(-6) x 1-1.5 µm Spot tests: thallus, cortex and medulla K-, C+ red, P-, I- Secondary metabolites: thallus with gyrophoric acid and a trace of lecanoric acid. Substrate and ecology: on siliceous rocks in the open, in wind-swept sites, mostly on steeply inclined, exposed surfaces in alpine or subalpine habitats World distribution: widespread in mountain ranges of the Northern Hemisphere, especially in Europe and North America and extending into South America, Australia, and South Georgia Sonoran distribution: higher mountains of Arizona and southern California.