Life habit: lichenized Thallus: crustose, elongate lobed, margin abrupt at edge, with elongated lobes 0.5-2 mm long, 0.5-1 mm wide; prothallus: absent surface: yellowish orange, pruinose; soralia present, delimited, marginal, on lobe tips; soredia fine cortex: cellular, 20-40 µm thick, with granules insoluble in K; medulla prosoplectenchymatous, with granules insoluble in K Apothecia: rare, adnate, 0.4-1 mm diam, lecanorine disc: orange, flat, epruinose margin: persistent, slightly raised; thalline margin present, concolorous with thallus; proper margin visible or not, concolorous with disc parathecium: elongate to oval cells; exciple below hypothecium amorphous epihymenium: golden, K+ red, H-, 10%N-, cN-, C- hymenium: hyaline, 55-85 µm tall paraphyses: with 1-2 tip swollen cells, not branched or with few branches; subhymenium hyaline asci: cylindrical, 8-spored ascospores: hyaline, 2 locules, ellipsoid, 12.5-15.5 x 5.5-7 µm, isthmus 1.5-3 µm, spore end wall thin Pycnidia: present, totally immersed, ostiole orange Spot tests: apothecial margin K+ red, H-, 10% N-, cN-, C-; thallus K+ red, H-, 10%N-, cN-, C-; medulla IKI- Secondary metabolites: parietin, fallacinal, emodin, and teloschistin. Substrate and ecology: on non-calcareous or calcareous rocks World distribution: Europe, North America Sonoran distribution: Arizona and southern California. Notes: Caloplaca decipiens is characterized by its distinctly radiating convex, laterally touching lobes, which are sorediate on the tips. In the central portions of the thallus soredia develop from short lateral lobes. Caloplaca decipiens differs from C. cirrochroa in having broader, higher, more convex lobes that branch more at the tips. Caloplaca stellata also has terminal soralia but the soralia do not expand, and the lobes are narrower and shorter than in C. decipiens.