Thallus: adnate to rather loosely adnate, ± appressed throughout, foliose, up to 11 cm diam., lobate lobes: short and rounded to somewhat elongate, contiguous to imbricate, only rarely discrete, (0.3-) 1-2 (-3) mm broad, ± flat upper surface: olive-brown to reddish brown or dark brown, at times distinctly paler and more yellowish at the periphery, smooth to weakly wrinkled or pitted on the lobe ends, inward usually somewhat rugose or fissured, sometimes strongly so; dull throughout or slightly shiny on the lobe ends, occasionally lightly pruinose isidia: sparse to dense, pustular, 0.06-0.2 (-0.3) mm diam., sometimes proliferating to form rather deep patches, these at times resembling soralia, especially when abraded lower surface: very dark brown to black sometimes paler on the lobe ends; ± smooth and dull; moderately rhizinate, the rhizines concolorous with the lower surface Apothecia: rare, up to 3.5 mm diam., sessile to short stipitate, concave or flattening, the margin entire to weakly crenulate, becoming isidiate asci: clavate, 8-spored ascospores: ellipsoid, 8-10 x 4.5-6 µm Pycnidia: rare, immersed conidia: bifusiform to almost fusiform, 5-6.5 x 1 µm Spot tests: cortex K-, C-, KC-, P-, HNO3+ dark blue-green; medulla K-, C- or C+ rose, KC- or KC+ rose or red, P- Secondary metabolites: divaricatic acid (major), oxostenosporic and gyrophoric acid (both minor or trace), and unknown TE-3 (accessory). Substrate: rocks, very rarely on wood or bark World distribution: western North America, Europe, North Africa Sonoran distribution: central and southern California and Guadalupe Island (Baja California). Notes: In North America, the only species that might be easily confused with this one is N. loxodes, which can have similar spot test reactions, and also has pustular isidia. Although considerable overlap occurs, normally, that species has slightly paler thalli with lobes that are wider, thicker and more distinctly maculate, and the pustular isidia are also usually somewhat larger. Chemically, the two are very distinct, since N. loxodes produces glomelliferic, glomellic and perlatolic acid, which give a distinctive KC+ red turning dingy orange-red spot test in the medulla. Neofuscelia verruculifera often has a KC- spot test, although the presence of accessory gyrophoric acid can result in spot test reactions confusingly similar to those of N. loxodes. Among collections examined, this species was occasionally confused with various sorediate species of Melanelia such as M. disjuncta (all HNO3-).