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, weakly convex when young, later strongly convex to bullate, with labriform brown soralia (often lacking) upper surface: greenish brown to castaneous or dark brown, shiny; margin: crenulate, not or slightly upturned, concolorous with upper side soredia: if present, brown, farinose to granular, in labriform soralia upper cortex: up to 110 µm thick, composed of thick-walled hyphae Apothecia: up to 0.5 (-0.7) mm diam., marginal or on the underside of ascending squamules; disc: reddish to dark brown, convex, epruinose, egyrose; margin: not prominent even when young, 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, 7-13 x 2-2.5 µm Pycnidia: sessile, black, attached marginally or to the underside of the squamule conidia: filiform, 7-11 x c. 1 µm Spot tests: upper cortex K-, C-, KC-, P-; medulla K-, C-, KC+ purple, P- Secondary metabolites: colensoic acid and related secondary products. Substrate and ecology: on charred bark and wood of conifers in conifer forests at 1480-2640 m alt. World distribution: Africa, Europe, and North America Sonoran distribution: Arizona, California, and Chihuahua; uncommon. Notes: The species differs from H. anthracophila in forming darker, more convex or agglomerate squamules with a brown margin and brown soralia, and in lacking fumarprotocetraric and protocetraric acids (cortex P-).