Life habit: lichenized Thallus: crustose, elongate lobed, margin abrupt at edge, with elongated lobes 1.5-2 mm long, 0.3-1 mm wide, prothallus: absent surface: orange, pruinose, without asexual propagules cortex: cellular, 5-10 µm thick, granules absent; medulla prosoplectenchymatous, without granules Apothecia: adnate, 0.3-1 mm, lecanorine disc: orange, flat, epruinose margin: persistent, flush; thalline margin present, concolorous with thallus; proper margin not visible parathecium: consisting of radiating hyphae; exciple below hypothecium prosoplectenchymatous epihymenium: golden, K+ red, H-, 10%N-, cN-, C- hymenium: hyaline, 60-90 µm tall paraphyses: 2-3 tip cells swollen, not branched or with few branches; subhymenium hyaline asci: cylindrical, 8-spored ascospores: hyaline, 2 locules, ellipsoid, 12.5-14 x 5.5-7 µm, isthmus 4-5.5 µm, spore end wall thin Pycnidia: present, totally immersed 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, teloschistin, and parietinic acid. Substrate and ecology: on non-calcareous rocks. World distribution: western North America Sonoran distribution: southern California, Baja California, Baja California Sur, Sonora, and northern Sinaloa. Notes: Caloplaca ignea has flattened and lighter orange lobe tips than C. impolita, C. brattiae, and also C. saxicola. The lobes of C. impolita are generally much shorter and narrower than in C. saxicola. The lack of crystals and granules in the medulla and the narrower spore isthmus separates C. impolita from C. appressa.