Thallus: squamulose, lobulate or areolate in central parts and effigurate at the margin squamules: elongate (rarely rounded) and irregularly incised, 0.3-1.3 mm in diam., moderately to strongly convex, tips often flexed downward surface: light gray to dark bluish gray, sometimes pale green or light beige, dull, esorediate upper cortex: usually distinctly developed, 15-35 µm thick, composed of densely entangled hyphae, outermost epinecral layer hyaline, 5-15 µm thick, inner part often with a brown layer 10-15 µm thick medulla: 20-100(-250) µm thick; photobiont: algal layer: 45-130 µm high, inspersed with crystals of gyrophoric acid; 6-13 µm in diam. Apothecia: flexuose (rarely rounded), mostly sessile with a constricted base, rarely appressed between lobules, 0.6-2(-2.7) mm in diam disc: dark gray to black, sometimes with a brownish tinge, dull, epruinose, flat or weakly convex margin: prominent when young, persistent but ±level with disc in old apothecia, lighter than disc, especially at the outside, dull exciple: pale brown to olive-brown at the margin, pale gray within, laterally 50-130 µm wide, basally 75180 µm wide, composed of densely entangled, hyphae with broadly cylindrical lumina of 1.5-3 µm, apically up to 6 µm diam.; epihymenium: 10-25 µm thick (poorly delimited against hymenium), sordid olive-brown hymenium: pale yellowish brown, (45-)55-70 µm tall; paraphyses: hyaline, branched and anastomosing, lumina 1-2 µm, apically 1.2-3 µm wide; subhymenium: 35-75 µm high; hypothecium: hyaline to pale brown, 20-35 µm high ascospores: usually sparse, hyaline, simple, (7-)8-9.1(-10) x (3-)3.9-4.3(-5) µm Pycnidia: usually numerous, globular, semi-immersed, ochre to dark brown, (70-)140-250 µm in diam.; wall: hyaline conidia: bacilliform, 6-8 x 0.7 µm Spot tests: thallus K-, C+ red, KC+ red, P-, UV- Secondary metabolites: gyrophoric acid. Substrate and ecology: on acid soil, from sea-level up to c. 1500 m altitude World and Sonoran distributions: coastal regions and coast ranges of southern California and Baja California. Notes: In the past, T. glaucopholis was mostly identified as T. wallrothii (e. g. Brodo et al. 2001). That European species is similar, but distinguished by mostly smaller, more appressed lobules, isidia that are soon abraded and leave ecorticate, punctiform scars on the thallus, and a pseudoparenchymatous cortex of anticlinally arranged hyphae.