Thallus: adnate to loosely adnate appressed throughout or occasionally slightly reflexed at the periphery, foliose, up to 8 (-10) cm diam., lobate lobes: short and rounded to somewhat elongate, discrete to more often contiguous or subimbricate, 1-4 (-6) mm broad, ± flat upper surface: olive-green or olive-brown to rather dark reddish brown, smooth to weakly pitted or rugulose near the periphery, inward usually somewhat more strongly rugose; dull throughout or occasionally shiny, especially near the periphery; sometimes with small and very obscure, concolorous pseudocyphellae on the lobes; sorediate or isidiate or (usually) both isidia: arising within but also between the soralia, cylindrical, not or infrequently branched, to 0.2 (-0.4) mm long and 0.02-0.06 mm diam. soredia: granular, frequently becoming brownish and isidioid or isidiate; in laminal soralia that often arise from the obscure pseudocyphellae and are punctiform and discrete, or become ± confluent in central parts lower surface: pale brown to dark brown or black, often paler at the periphery; ± smooth to rugose, dull to rather shiny; moderately rhizinate, the rhizines concolorous with the lower surface Apothecia: rare, up to 2.5 mm diam., sessile, ± flat, the margin entire when young, soon sorediate and isidiate asci: clavate, 8-spored ascospores: ellipsoid, 10-13 x 5.5-7 µm Pycnidia: rare, immersed conidia: weakly fusiform to weakly bifusiform, 5.5-7 x 1µm Spot tests: cortex K-, C-, KC-, P-, HNO3-; medulla K-, C+ rose-red or red, KC+ red, P- Secondary metabolite: lecanoric acid. Substrate: bark or wood, rarer on rocks World distribution: much of temperate and boreal North America and Europe, North and Central Africa, Asia Sonoran distribution: infrequent, only in the California part of the Sonoran region. Notes: The presence of both soredia and true, very slender isidia on the lamina, a C+ medulla, and a mostly appressed thallus will distinguish this species from most others in the genus. Melanelia subargentifera has soredia which sometimes become isidioid, but they are much coarser than the isidia of M. subaurifera, which also lacks the hyaline cortical hairs characteristic of that species. Melanelia fuliginosa sometimes has the thallus surface eroded around its isidia, and this situation has been mistaken for the presence of soredia.