Thallus: endolithic, scarcely epilithic; prothallus: not developed areoles: either lacking or continuous or dispersed, flat, irregular, up to 0.5 mm in diam. surface: if visible: white, pale gray, or sand-colored, rough medulla: white, I- or partially weakly I+ violet Apothecia: black, loosely attached with strongly constricted base, 0.6-1.4(-4.2) mm in diam. disc: black, concave to flat (however sometimes waved) to convex (rarely subglobose), dull, epruinose or faintly pruinose; margin: black, persistent (more rarely evanescent), dull to shiny, often more or less undulate, sometimes gray outside and vertically striated exciple: unpigmented or sometimes pale purplish brownish (cf. melaenida-red), peripherally black, 30-80 µm wide, ochre opaque inside due to crystalline substances, that dissolve in K, C- epihymenium: black with a green, olive or brown tinge (cinereorufa-green) usually present, sometimes lacking), 8-14 µm thick hymenium: colorless or more rarely with a pale violet tinge (cf. melaenida-red), 37-57 µm tall, I+ blue; paraphyses: simple, rarely branched, apical cells 3.5-5 µm wide, globose, with dark caps subhymenium: colorless (in lactic blue), 25-50 µm thick hypothecium: colorless to pale brown, 40-90 µm thick asci: clavate, 3550 x 11-14 µm, 8-spored ascospores: oblong, (6-)8-11.9(16) x (2-)2.6-3.8(-5) µm length to width: 2.3-3.7 : 1, mean volume 42-105 µm3 Pycnidia: graphidoid, immersed in tiny whitish areoles conidia: cylindrical, (6-)8.4-12.3(16) x 1-1.3 µm Spot tests: cortex and medulla K-, C-, KC-, P- Secondary metabolites: 4-O-demethylplanaic acid, sometimes in addition with traces of planaic acid, or (more rarely) acid deficient. Substrate and ecology: in open habitats on acidic rocks, lowland to alpine, most common in montane and subalpine areas World distribution: bipolar and extending into the tropics in alpine areas Sonoran distribution: most common in Arizona and southern California, Baja California and Baja California Sur.