Thallus: crustose, granular, rimose to barely rimose-areolate in the thickest part, 4-7 cm across, less then 2 mm thick when on rock (less than 0.5 mm thick on wood or bark but appearing thicker when the substrate is irregular) granules: 0.1-0.2 mm in diam., or occasionally in part consisting of tiny dispersed but crowded convex areoles areoles: dispersed to crowded, verrucose or rugose, tiny (0.1-0.2 mm in diam.) surface: whitish gray to pale yellow or pale pinkish buff, the granules paler than the non-granular parts, smooth to subisidiate to subsorediate Apothecia: common, circular to somewhat irregular, adnate, 1-3 mm in diam. disc: scarlet-red to deep rusty red or reddish brown, plane to convex and rugulose at maturity margin: thin, concolorous with thallus, soon disappearing amphithecium: thin, concolorous with the thallus, soon disappearing exciple: disappearing with age epihymenium: deep red, encrusted with haemoventosin crystals hymenium: hyaline below to red above; hypothecium: hyaline asci: clavate, 8-spored ascospores: hyaline, 3(-6)-septate, narrowly fusiform, usually straight but sometimes curved, 30-53 x (2-)3-4(-5) µm Pycnidia: black, on or among the areoles, with a blue-black, K- wall conidia: bacilliform, 5-8 x 0.7-1 µm Spot tests: thallus K-, C-, KC+ yellow, P- Secondary metabolites: apothecia with haemoventosin and thallus with usnic and divaricatic acids, atranorin (low conc. and possibly a contaminent) and an unknown. Substrate and ecology: primarily on bark of conifers or wood (especially Arctostaphylos spp.), occasionally on rock in woodlands World distribution: western North America, 600-1200 m Sonoran distribution: southern California. Notes: The report of the species from southern California dating to Hasse (1898a) was confirmed by Kalb and Staiger (1995) and May (1997).