Bright orange foliose lichen. Apothecia abundant. Underside pale with abundant rhizines. Pycnidia immersed or protruding, dark.
Continental temperate North America (i.e. not coastal).
Dry bark and woody debris, generally relatively high elevation.
X. hasseana is nearly identical, but fortunately has a disjunct range, occuring along the coast, at least in the southwest. Its spores have thicker septum; its rhizines are longer; its lobes are somewhat narrower (according to Lindblom).
Some Xanthoria (e.g. X. elegans and X. polycarpa) can look superficially similar, but on close inspection have few or no rhizines (just occasional stubby little things called hapters), while Xanthomendoza montana typically has conspicuous, abundant rhizines.