Life habit: lichenized Thallus: crustose, areolate, margin abrupt at edge, without elongated lobes; prothallus: present, black surface: yellowish orange or greenish yellow, smooth, without asexual propagules cortex: cellular, 1521 µm thick, granules absent; medulla paraplectenchymatous, without granules Apothecia: adnate, 0.3-1 mm, lecanorine disc: brownish orange, flat or convex, epruinose margin: persistent or disappearing, flush; thalline margin present, concolorous with thallus; proper margin visible, little lighter than disc parathecium: consisting of radiating hyphae or elongate to oval cells; exciple below hypothecium irregular hyphae epihymenium: golden, K+ red, C- hymenium: hyaline, 70-85 µm tall paraphyses: 1-2 tip cells slightly swollen, with few branches or with some branching; subhymenium hyaline asci: cylindrical, 8-spored ascospores: hyaline, 2 locules, ellipsoid, 12.515.5(-17) x 5.5-8.5 µm, isthmus (3.5-)4-5.5 µm, spore end wall thin Pycnidia: present, totally immersed, ostiole orange Spot tests: apothecial margin K+ red; thallus K+ red Secondary metabolites: parietin, fallacinal, emodin, and teloschistin. Substrate and ecology: on non-calcareous rock or occasionally on calcareous rocks World distribution: worldwide Sonoran distribution: Arizona, southern California, Baja California Sur, western Chihuahua, and Sonora. Notes: Caloplaca flavovirescens has a fairly thin or somewhat thickened yellow-green areolate thallus with darker orange apothecia.