Thallus: squamulose, rosette-forming, thick, orbicular or irregular, up to c. 10 cm across or in small patches 1-3 mm wide squamules: up to 1.2 mm wide, overlapping, irregularly rounded to crenate, sometimes subdivided into smaller squamules (imbricate), subsquamules 0.15-0.5 mm wide, squamule margin strongly raised and wavy, slightly to deeply concave, separated by broad irregular fissures upper surface: yellowish brown to reddish brown or dark brown, becoming moderate yellowish brown when wet, the edges usually pale to dark gray, shiny upper cortex: prosoplectenchymatous, with cells 5-8 x 3-3.5 µm, with a yellow-brown layer just below the 15 µm thick epinecral layer, overall 30-40 µm thick medulla: with prosoplectencymatous hyphae; algal layer: c. 80 µm thick; algae: 6-10 µm in diam. lower cortex: c. 50 µm thick lower surface: pale gray, without rhizines Apothecia: broadly sessile, sometimes crowded, 0.4-1.7 mm in diam. disc: dark brown or dark blackish brown, paler and redder when wet, dull to slightly shiny, plane to slightly convex or turgid, epruinose margin: thalline, concolorous with thallus, +level with disc, entire or slightly crenulate, persistent or rarely becoming thin, up to c. 0.1 mm wide amphithecium: with a cortex up to c. 30 µm thick and hyphae 3-4 µm wide, with an algal layer filling the margin at the top, 75-100 µm thick with uneven upper edge below hypothecium parathecium: sometimes evident from above, with conglutinated paraplectencymatous cells with lumina 2-3 µm diam. epihymenium: 15-20 µm thick (dark) red-brown, K+ pale red (intensifying) hymenium: hyaline, 60-75 µm tall; paraphyses: coherent, 1.5-2.5 µm in diam. in mid-hymenium cells, hyaline, upper cells slightly constricted at septa, tips clavate, mostly reddish brown pigmented, 3-6 µm wide; hypothecium: hyaline to pale yellow, ±prosoplectenchymatous, with conglutinate hyphae with lumina 3-5 x 2-3 µm, up to 40 µm thick in center asci: clavate, 55 x 12 µm, Bacidia-type, 8-spored ascospores: hyaline, (0-)1-septate, narrowly ellipsoid to ellipsoid-fusiform, 14-18(-20) x 3-4(-4.5) µm Pycnidia: occasionally present, immersed, 50-100 µm in diam.; wall: hyaline below, medium brown around the ostiole; conidiophores: irregularly branched; conidiogenous cells: cyilindrical-elongate, conidia: relative long filiform, ±straight to moderately curved, 18-25 x 0.8 µm Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: on siliceous rock (sandstone) World and Sonoran distribution: known from southern California, Channel Islands and Baja California. Notes: Confusion of L. brattiae with Psora sp. is possible, because of their squamulose thalli, however the apothecia in Psora lack an amphithecium. Because of the prosoplectenchymatical cortical cells with its pigmented rim, the new species is most related to Lecania spadicea and L. brunonis (see discussion under L. brunonis). The new species is characterized by its often concave and ±imbricate squamules with wavy and pale to dark grayish edges. It is similar in some ways to L. brunonis, but that species differs in having a verrucose-areolate-subsquamulose thallus, that sometimes has a raised margin. Also it has a somewhat thinner algal layer and hypothecium, a +soon excluded amphithecium, and wider (5-6 µm) ellipsoid to broadly ellipsoid ascospores.