Life habit: lichenized Thallus: little or none, crustose, continuous or areolate, margin thinning at edge, without elongated lobes; prothallus: absent surface: orange or gray, smooth, without asexual propagules cortex: cellular, 28-56 µm thick, granules absent; medulla without granules Apothecia: adnate, 0.4-0.8 mm in diam., lecanorine disc: orange, flat or concave, epruinose margin: persistent, raised; thalline margin absent; proper margin visible, concolorous with disc parathecium: consisting of radiating hyphae; exciple below hypothecium irregular hyphae epihymenium: golden, K+ red, C- hymenium: hyaline, 70-85(-90) µm tall paraphyses: 2-3 tip cells slightly swollen, not branched; subhymenium hyaline asci: cylindrical, 8-spored ascospores: hyaline, 2 locules, ellipsoid, 11-18(-19.5) x 4-5.5(-8.5) µm, isthmus 1.5-3 µm, spore end wall thin Pycnidia: present, totally immersed, ostiole orange Spot tests: Thallus K- or K+ red Secondary metabolites: parietin, fallacinal, emodin, teloschistin, and parietinic acid. Substrate and ecology: on soil, non-calcareous rocks, or calcareous rocks World distribution: coastal, western North America Sonoran distribution: southern California, Baja California and Baja California Sur. Notes: Caloplaca luteominia var. luteominia has a thallus that is quite variable from very little to fairly well developed. The proper margins of the apothecia are relatively thick and raised. The narrow spore isthmus separates this from other similar species. The discs in this variety are dull orange compared with the bright red of var. bolanderi.