Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.
Thallus: squamulose squamules: up to 0.8 (-1.3) mm diam., normally ascending and geotropically oriented, concave or plane when young, later weakly to strongly convex upper surface: grayish green to greenish or medium brown, shiny; margin: entire, not or slightly upturned, lighter than upper side or white soredia: gray, farinose to granular, in labriborm soralia upper cortex: up to 100 (-130) µm thick, composed of thick-walled hyphae Apothecia: up to 0.8 (-1.3) mm diam., marginal or on the underside of ascending squamules; disc: reddish to dark brown, convex, epruinose, egyrose; margin: more or less prominent when young, later excluding, entire; exciple: composed of closely conglutinated hyphae, colorless to pale brown, not containing crystals, K-, N-; hypothecium: colorless; epithecium: light brown, not containing crystals, K-, N-; paraphyses: with swelling and pigment cap in apical cell asci: with a well developed tholus containing an amyloid tube ascospores: narrowly ellipsoid to fusiform, simple or more rarely 1-septate, 7-13 x 1.5-2.5 µm Pycnidia: sessile, black, attached marginally or to the underside of the squamule conidia: filiform, 6.5-12.5 x c. 1 µm Spot tests: upper cortex and soralia K-, C-, KC-, P+ orange/ red, medulla K-, C-, KC+ purple, P- Secondary metabolites: colensoic acid and related secondary products, fumarprotocetraric acid, and protocetraric acid. Substrate and ecology: on bark and wood of conifers, usually charred, in conifer forests at 530-3050 m alt. World distribution: North America, Australia, Europe and Asia Sonoran distribution: fairly common in Arizona, Baja California, Sonora and Chihuahua.