Thallus: crustose to squamulose, effuse, up to 0.5-1.5 mm thick, verrucose-areolate or subsquamulose to more rarely squamulose, c. 4 cm across; prothallus: absent areoles (squamules): irregularly rounded to crenate, sometimes with very small squamules aggregated into larger, irregularly angular areoles, plane to slightly convex, dispersed or adjacent to imbricate, 0.2-1 mm wide, separated by broad fissures, sometimes with margins upraised and sometimes incised upper surface: grayish to yellowish brown to red-brown or dark brown, becoming moderate yellowish brown, concolorous or somewhat paler brown when wet, with concolorous or sometimes paler areole edges, dull to upper cortex: yellow-brownish, paraplectenchymatous with unoriented hyphae with narrow lumina 3-4 µm wide but in places prosoplectenchymatous with anticlinal and often branched hyphae, overall 30-40 µm thick, covered by an epinecral layer c. 30 µm thick medulla: with weakly paraplectenchymatous hyphae; algal layer: up to 50-100(-200) µm thick; algae: 8-10 µm in diam. lower surface: rarely developed towards the margin, pale or white lower cortex: absent or partly developed near the Apothecia: broadly sessile, scattered to grouped, 0.5-1 mm in diam. disc: deep or dark brown or dark grayish brown, often paler and redder when wet, with dark dots, slightly shiny, plane to convex or turgid, epruinose, or occasionally finely and +lightly pruinose margin: thalline, concolorous with thallus, up to 0.1(-0.2) mm wide, entire or finely toothed, +level with disc, persistent or becoming +excluded amphithecium: with a c. 30 µm thick cortex composed of unoriented hyphae 3-4 µm wide and with elongated lumina c. 1 µm wide, with an algal layer: filling the margin, 75-100 µm thick with uneven upper edge below hypothecium parathecium: often evident from above and occasionally well-developed and conspicuous, paraplectenchymatous, up to c. 70 µm wide toward outer edge, red brown at outer edge, cells strong conglutinate 2-4 µm in diam. epihymenium: red-brown to dark brown, with diffuse pigment (K+ pale red) and sometimes with very fine pigment granules (soluble in K), 15-20 µm thick hymenium: hyaline, 60-75 µm tall; paraphyses: +coherent, 2-2.5 µm in diam. below, upper cells slightly constricted at septa, the tips clavate, up to 3-4(-5) µm wide, hyaline or brown; hypothecium: pale yellow to pale yellowish brown, up to 150 µm thick in center; hyphae: unoriented to prosoplectenchymatous, conglutinate, c. 4 µm wide, lumina 3-5 x 2-3 µm asci: clavate, Bacidia-type, 50-60 x 12 µm, 8-spored ascospores: hyaline, (0-)1-septate, very rarely a few 3-septate, ellipsoid to broadly ellipsoid, 10-15(-18) x (4-)5-6 µm Pycnidia: ellipsoid, up to 200 µm tall; ostiole: up to 0.3 mm wide, dark brown at upper side and rugulose; conidiogenous cells: elongate, filamentous, branched manly basally, c. 15 x 2 µm. conidia: relative long filiform, 16-25 x 0.8 µm Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: on siliceous rock mainly sandstone and sometimes serpentine, occasionally on bone World and Sonoran distribution: southern coastal California to Baja California Sur. Notes: Lecania brunonis, originally described from the central California coast (Oakland Hills as well as "San Bruno Mountains"), is extremely variable in morphology and color of its thallus and apothecia, and is treated here in a broad sense. Lecania brunonis shows some similarity to L. spadicea, a species common in Mediterranean Europe and not yet found in the Sonora area. The latter species is characterized by having an effigurate thallus, that often is pruinose, and has ascospores, that are somewhat smaller (10-14 x 4-5[-6] µm). Lecania brunonis is characterized by having a shiny, brown, verrucose-areolate-subsquamulose thallus with upturned margins, and the presence of some imbricate or incised squamules. Species in the Sonoran region with which L. brunonis can be confused are: L. toninioides, that differs by usually having pale-rimmed areoles with appressed margins and a thicker cortex and epinecral layer, discs that are +unchanged when wet, and longer ascospores; L. pacifica and L. brattiae (see notes under those species); L. fructigena, that differs in having more convex and often basally constricted thallus subunits, somewhat narrower, +oblong-ellipsoid ascospores, pigmented granules in the epihymenium, and is more often found in coastal areas. Lecania inundata differs in having a papillate surface to the areoles, a brownish tinged thallus, that turning greenish when wet, and a phenocortex, and it occurs primarily on calcareous substrates. According Brodo et al. (2001) L. brunonis also occurs in the NW corner of Arizona, however we have not seen material of that locality and the habitat is an unlikely range extention.