Thallus: strongly squamulose, areolate; prothallus: indistinct areoles: dark brown to black on the underside contiguous to dispersed, flat, irregularly ear-shaped in outline, 0.5-1.5 mm in diam. surface: light brown with gray margins, esorediate medulla: white, I- Apothecia: black, sessile, slightly constricted at base, up to 2.5 mm in diam. disc: flat to moderately convex, dull, epruinose or indistinctly pruinose margin: black, persistent, dull to shiny exciple: marginally with a thin, 15-20 µm wide, black to dark brown rim and a hyaline to dull beige (by crystalline immersion) interior part, peripherally 30-80 µm wide, K-, C-, P- epihymenium: dark brown with a weak olive tinge, c. 10 µm thick hymenium: hyaline, (65-)73-84(-95) µm tall, I+ orange; paraphyses: simple, occasionally branched and anastomosing, c. 2 µm in diam., with slightly swollen apical cells of 3-4 µm in diam. subhymenium: unpigmented, (20-)25-35(-45) µm thick hypothecium: dark brown to almost black asci: clavate, Lecidea-type, 55-75 x 12-16 µm, 8-spored ascospores: hyaline, simple, ellipsoid, (9.5-)13-15 (-19) x (4.5-)5-6.5(-8) µm, length-widthindex 2.1-2.3 Pycnidia: immersed, graphidoid conidia: cylindrical, 7.5-11 x 1-1.3 µm [studied in 2 specimens] Spot tests: cortex and medulla K-, C-, KC-, P- Secondary metabolites: perlatolic acid. Substrate and ecology: on exposed acidic rocks in the lower montane zone World distribution: only known in its type collection Sonoran distribution: not recorded; to be expected southwards in California. Notes: Lecidea brodoana is related to Lecidea fuscoatra. It has a rather pronounced squamulous thallial areolation (a character, which, although less pronounced, sometimes is also found in the very variable L. fuscoatra) and possesses perlatolic acid instead of gyrophoric acid. It is named in honor of the great lichenologist Irwin M. Brodo.