Thallus: adnate to loosely adnate, appressed but often somewhat raised on the margins and ends of the lobes, foliose, up to 8 (-11) cm diam., lobate lobes: short and rounded to somewhat elongate, discrete to more often contiguous or imbricate, (1-) 2-4 (-7) mm broad, ± flat upper surface: pale olive-brown to dark brown, often with a distinctly reddish or yellowish cast, smooth to distinctly rugose or pitted at the periphery, inward usually somewhat more strongly rugose; dull throughout or occasionally somewhat shiny, very often lightly to rather heavily pruinose, especially near the lobe margins; usually bearing tiny, hyaline, cortical hairs especially near lobe edges, these dense to sparse, but rarely missing altogether; without typical pseudocyphellae, but the lobes in places with linear, sometimes pale, pseudocyphelloid lines on the margins (like those of M. glabra) soredia: granular to occasionally rather strongly isidioid, brown to dark brown (whitish when abraded), in laminal and marginal (rarely weakly labriform) soralia; laminal soralia: mostly developing from small pustules by gradual dissolution of the cortex; soralia: punctiform to weakly capitate, often becoming numerous and ± confluent in older parts of the thallus lower surface: dark brown to black, paler at the periphery, smooth to weakly rugose or weakly trabeculate, dull to somewhat shiny; moderately rhizinate, the rhizines ± concolorous with the lower surface Apothecia: rare, up to 3 mm diam., sessile, concave to ± flat, the margin very soon becoming sorediate asci: clavate, 8-spored ascospores: ellipsoid to broadly ellipsoid, 11-13 x 7-8.5 µm Pycnidia: rare, immersed conidia: acerose to weakly fusiform or weakly bifusiform, 5-7.5 x 1 µm Spot tests: cortex K-, C-, KC-, P-, HNO3-; medulla K-, C+ rose-red or red, KC+ red, P- Secondary metabolite: lecanoric acid. Substrate: bark, wood, and rocks World distribution: western and northern North America, Europe, Central Africa, Asia Sonoran distribution: forested regions, usually between 1500 and 2500 m in Arizona, lower in California. Notes: This is the most common sorediate species of Melanelia in the study area, especially on bark. The usually somewhat uplifted lobes (i.e., not appressed out to the ends), presence of at least sparse hyaline cortical hairs, possession of both laminal and marginal soralia, and the C+ medulla should adequately distinguish it from all others. Much rarer (in the study area) M. subaurifera is sometimes confused, but has primarily laminal soredia, usually with very slender true isidia interspersed, and is usually appressed. The most closely related species is M. albertana, known from only a single collection in the Sonoran region, and differing by the very distinctly labriform soralia.