squamules: (0.25-) 0.5-2 (-3) mm wide, densely aggregated surface: blackish brown when dry, dirty brownish olive or brownish yellow when moistened attachment: by rhizoidal strands or small, indistinct umbilicus Apothecia: semi-immersed to sessile, zeorine, up to 0.5 mm wide, with persisting thalline margin; disc: at first punctiform, later open, often depressed, brownish; exciple: distinct, of strongly gelatinized hyphae, 12.5-20 µm wide, hyaline; epihymenium: yellowish-brown; hymenium: up to 125 µm high, hyaline, iodine reaction variable; paraphyses: distinctly septate, branched and anastomosing, apical cells thickened (3.5-5 µm) asci: 16-32-spored ascospores: small, simple, hyaline, broadly ellipsoid to globose, 5 (-7.5) x 5 µm; walls: thin Pycnidia: immersed, globose, 0.075-0.1 mm wide; pycnidial wall: convoluted with age conidia: cylindrical, hyaline, 3 x 1 µm Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: on granite, rhyolite, rarely on calcareous crusts over siliceous rock (caliche) or limestone; on sheltered or shaded boulders in rocky slopes, wash -es etc.; coastal to montane World distribution: SW North America Sonoran distribution: central and southern Arizona; Baja California Sur, Sonora and Sinaloa. Notes: It grows intermingled with other crustose-squamulose species (e.g. Phloeopeccania spp.) and sometimes it is hard to separate. Moistening identifies the subgelatinous nature of the thallus because of a distinct change in color from blackish brown to lighter brownish olive or brownish yellow.