Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.

Thallus: appressed, up to 9 (-12) cm broad; texture: cartilaginous; branching: variable; budding: present lobes: contiguous, 0.5-4 mm broad, sometimes black bordered; profile: pinched and swollen; width/height ratio: 1-15; tips and axils: often minutely perforate upper surface: greenish gray to brown, dark mottled, becoming rugose soredia: predominantly terminal, both on the main lobes and short, upturned, lateral lobes, sometimes with secondarily diffuse laminal soredia; isidia absent, lobules sparse or none medulla: hollow; ceiling of cavity: white or dark; floor of cavity: dark lower surface: black, entire; Apothecia: not seen in local material Pycnidia: rare conidia: not seen Spot tests: cortex K+ yellow, C-, KC-, P+ pale yellow, UV-; medulla K-, C-, KC+ orange-red, P- Secondary metabolites: upper cortex with atranorin and chloroatranorin; medulla with physodic acid (major), 3-hydroxyphysodic acid (accessory, frequency about 20%), 2'-O-methylphysodic acid (minor accessory), unknown C8 (minor accessory). Substrate and ecology: typically on bark or wood, especially conifers in montane and subalpine forests, also on mosses or detritus over rock or alpine sod World distribution: circumpolar arctic, boreal, and montane in continental climates in Europe, Asia, and North America, south through Mexico along the cordillera well into South America; high mountains in Africa Sonoran distribution: southern Rocky Mountains. Notes: See discussion under H. austerodes.