Life habit: lichenized Thallus: crustose, continuous, without elongated lobes; prothallus: absent surface: gray, smooth, isidiate isidia: coralloid, laminal cortex: cellular 10-15 µm thick; medulla prosoplectenchymatous, with granules insoluble in K Apothecia: adnate, 0.3-1 mm in diam., lecanorine disc: orange, flat, pruinose margin: persistent, raised; thalline margin present, concolorous with thallus; proper margin visible, concolorous with disc parathecium: consisting of radiating hyphae; exciple below hypothecium cellular (paraplectenchymatous) epihymenium: golden, K+ red, H-, 10%N-, cN-, C- hymenium: hyaline, 85-110 µm tall paraphyses: tip cells not swollen, frequently branched; subhymenium hyaline asci: cylindrical, 8-spored ascospores: hyaline, 3 locules, ellipsoid, 18-22 x 10-12.5 µm, spore end wall thin Pycnidia: not observed Spot tests: apothecial margin K-, H-, 10% N-, cN-, C-; thallus K-, H-, 10%N-, cN-, C- Secondary metabolites: unidentified anthraquinones. Substrate and ecology: on bark World distribution:: Mexico Sonoran distribution: Baja California Sur. Notes: Caloplaca lagunensis is very distinctive with its light gray isidiate thallus and dull orange apothecia. The apothecial margins are usually isidiate and often slightly yellowish orange. The isidia are coralloid and often with bluish tips. If apothecia are present the spores have 3 locules.