Thallus: crustose, warted-areolate areoles: well delimited, isodiametric, moderately to strongly convex, 0.15-0.60 mm in diam. surface: yellowish green to greenish ochre, dull, esorediate cortex: poorly developed, composed of hyaline hyphae surrounded by brownish granules, 10-15 Ám thick medulla: 0-100 Ám thick; algal layer: 150175 Ám thick; photobiont: chlorococcoid, 6-12 (-16) Ám in diam. Apothecia: rounded to somewhat deformed, sometimes tuberculate, sessile with a constricted base or somewhat appressed among the areoles, 0.3-0.8(-1) mm wide disc: bluish gray often with a brownish or ochre tinge, sometimes nearly black, plane or moderately convex, pruinose margin: dark gray to black, thin, not prominent, exciple: (reddish) brown at the margin, darker brown within, laterally 30-70 Ám wide, basally 30-100 Ám wide, composed of radiating hyphae with brown cell walls epihymenium: ochre to greenish brown, granular, 5-10(15) Ám thick hymenium: hyaline to pale yellow, basal parts often olive-brown, 30-35(-45) Ám tall; paraphyses: hyaline but basally olive-green, with lumina of 0.7-1.2 Ám, apically sometimes brown with lumina 1-1.5 Ám wide, weakly to moderately branched and anastomosing subhymenium: olive brown (bases of paraphyses), 35-65 Ám thick hypothecium: dark brown, 80-125 Ám thick asci: clavate, ▒Biatora-type but axial body very indistinct, 8-spored ascospores: hyaline, simple or rarely 1-septate, narrowly ellipsoid, (6.5-)8.1-10.3(-13) x (2-)2.4-2.7(-3) Ám Pycnidia: immersed, pyriform, c. 90 Ám in diam., with brown walls conidia: filiform, 15-20 x 0.5 Ám Spot tests: thallus K+ yellow, C+ red, KC+ red, P- Secondary metabolites: gyrophoric and usnic acids. Substrate and ecology: on wood (preferrably conifers), 1370-2000 m World and Sonoran distribution: Sonora and Arizona. Notes: Lecidea trapelioides is not a member of Lecidea s. str. and perhaps related to L. leprarioides. Externally it is similar to Trapeliopsis granulosa and T. flexuosa (especially the areolate thallus), but it is distinguished by its different apothecial anatomy (exciple of radiating hyphae), ascus type, much smaller ascospores and the occurrence of both gyrophoric and usnic acids. For the distinction from L. leprarioides, see under that species.