Thallus: foliose to subfruticose, loosely adnate to nearly free growing, forming intact rosettes, 3-4 cm in diam., dichotomously lobate (at least terminally) lobes: sub-linear, elongate, weakly to strongly convolute, separate and subimbricate, 0.8-2 mm wide, becoming lobulate centrally; lobules: terete, 0.3-0.6 mm wide, subascending; main apices: subtruncate, smooth to crenate, eciliate upper surface: light yellow-green, smooth, shiny, epruinose and emaculate, without soralia, isidia, or pustulae medulla: white, with continuous algal layer lower surface: pale to dark brown, plane to canaliculated, moderately to densely rhizinate; rhizines: pale to dark brown, simple to tufted or occasionally branched, often projecting beyond the lobe margin, 0.5-1 mm long Apothecia: common, substipitate, 2-4 mm wide, laminal on thallus; disc: cinnamon-brown to dark brown; margin: smooth, pruina absent asci: clavate, 8-spored ascospores: not well developed Pycnidia: common, immersed conidia: bifusiform, 4-5 x 0.5 µm Spot tests: upper cortex K+yellow to orange, C-, KC-, P+ orange; medulla K+ yellow becoming dark red, C-, KC-, P+ orange Secondary metabolites: upper cortex with usnic acid (major); medulla with stictic acid (major), cryptostictic and norstictic acids (minor), constictic, connorstictic and peristictic acids (trace). Substrate and ecology: on acidic pebbles and adjacent soil, often in open, woodland habitats World distribution: western North and South America Sonoran distribution: locally common in Arizona and at intermediate elevations in the Sierra Madre Occidental of Chihuahua. Notes: Initially X. neowyomingica was described from a single location in Colorado. It now appears to occur fairly widely within the Sonoran region, and is locally common along the Pacific coast. This species is similar to the much more common salazinic acid containing species, X. wyomingica, but differs in producing terete lobulae and in containing the stictic acid chemosyndrome. It could be confused with X. standaertii because of their similar habitat preference and identical chemistry, but the latter has flattened rather than terete lobulae.