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

Life habit: lichenized, not lichenicolous Thallus: crustose, areolate, 2-6 cm in diam.; prothallus: strongly developed areoles: peltate, mostly close together forming a continuous thallus, rarely scattered, 0.3-0.8(-1.4) mm wide, 0.4-0.8 mm thick surface: usually gray, rarely gray-brown, or pale brown to brown where abraded, almost always strongly to very strongly convex, smooth, dull; medulla: white Apothecia: 0.3-0.9 mm in diam. disc: black, mostly flat with thin margin to convex-immarginate epihymenium: brown to brown-black, K+ strong red or sometimes K- hymenium: hyaline, 100-140(-160) µm tall; paraphyses: tips fused into a pseudoparenchymatous tissue; hypothecium: brown asci: clavate, 4(-5)-spored ascospores: dark brown to brown-black, muriform, many-celled, 22-42 x 10-18 µm Pycnidia: black, almost globose, on the prothallus or immersed in the areoles conidia: hyaline, filiform, 8-14 x 0.5-1.4 µm Spot tests: medulla K+ yellow, C-, KC-, P+ pale yellow Secondary metabolites: norstictic acid. Substrate and ecology: on acidic rocks, World distribution: arctic-alpine to temperate, western and northern North America and Greenland Sonoran distribution: Arizona and southern California.