Thallus: squamulose, sometimes poorly developed and then granular to indistinct squamules: up to 0.5-0.6 broad and 0.3-0.8 long, irregularly incised to lobate, appressed to raised from the substrate, scattered to crowded or imbricate surface: gray, somewhat shiny cortex: upper part 4-15 µm thick and composed of dead compressed hyphae, lower part paraplechtenchymatous, 10-20 µm thick Apothecia: usually abundant, biatorine, 0.3-0.6 mm wide, but often several apothecia grow into each other forming larger aggregates exciple: not visible from the outside, disc: pale yellow to yellow, round but becoming irregularily in outline, somewhat convex epihymenium: yellow-brown hymenium: hyaline, 50-60 µm tall; paraphyses: simple, cylindrical or sligthly tapering, tips to 2.5 µm; hypothecium: hyaline asci: clavate, 8-spored ascospores: hyaline, simple to 1-septate, narrowly ellipsoid to ovoid, 9.5-14 x 4-5 µm Pycnidia: normally lacking, instead the lower surface of the squamules are covered by conidiophores nidia: hyaline, ±globose, 4.5-6 µm wide Spot tests: disc K+ reddish, KC-, C- Secondary metabolites: calycin, pulvinic acid, pulvinic dilactone and vulpinic acid. Substrate and ecology: mostly on the bark of broad-leafed trees, sometimes on wood World distribution: North America, southern and central Europe, North Africa, and New Zealand Sonoran distribution: found twice in Arizona, on oak along a river and on juniper in a pinyon-juniper stand. Notes: This peculiar species is rare in the Sonoran region. Candelariella subdeflexa is characterized by its biatorine apothecia and its gray, squamulose thallus which may, however, be poorly developed. It is not likely to be identified as a Candelariella when sterile.