Thallus: squamulose; forming strongly convex structures up to 2 cm diam., usually lacking a hypothallus squamules: very thick, up to 0.5 mm thick and up to 2 mm wide, peripherally often with convex lobes, centrally becoming pulvinate upper surface: brownish, smooth upper cortex: paraplectenchymatous with irregularly thickened cell walls, 20-30 µm thick Apothecia: common, often proliferating; up to to 1.5 mm diam, with variously developed thalline margin; disc: brown, convex; exciple: subparaplectenchymatous, often 80-100 µm thick; hymenium: I+ blue-green, turning red-brown, 100-120 µm high asci: clavate, with apical amyloid sheets, 8-spored ascospores: simple, colorless, ellipsoid, 17-25 x 7-10 µm Pycnidia: not observed Spot tests: all negative Secondary metabolites: none detectable. Substrate and ecology: dry rock outcrops of granite or ultrabasic rocks, mainly at lower or middle altitudes (possibly also in the higher mountains) World distribution: only known from western North America from New Mexico to California and north to British Columbia Sonoran distribution: central and eastern Arizona and southern California. Notes: It is characterized by the very thick squamules and a tendency to develop numerous secondary lobules around the apothecia. The larger spore size distinguishes it from extreme forms of F. hookerioides, which is mainly a high altitude species. Fuscopannaria leucophaea is a much thinner species of moist river valleys.