Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2007. Lichen Flora of the Greater Sonoran Desert Region. Vol 3.
Life habit: lichenicolous Thallus: immersed, crustose, without elongated lobes; prothallus: absent; without asexual propagules cortex: absent Apothecia: adnate, 0.1-0.3 mm in diam., lecanorine disc: orange, flat, epruinose margin: persistent, flush; thalline margin absent; proper margin visible, concolorous with thallus parathecium: cellular (paraplectenchymatous); exciple below hypothecium amorphous epihymenium: golden, K+ red hymenium: hyaline, 50-55 µm tall paraphyses: tip cells not swollen, frequently branched; subhymenium hyaline asci: cylindrical, 8-spored ascospores: hyaline, 2 locules, ellipsoid, 10-12.5 x 5.5-7 µm, isthmus 3 µm, spore end wall thin Pycnidia: not observed Spot tests: apothecial margin K+ red Secondary metabolites: unidentified anthraquinones. Substrate and ecology: on Heterodermia over non-calcareous rocks World distribution: Mexico Sonoran distribution: Baja California Sur. Notes: Caloplaca endodermia is characterized by the orange coloration of the host thallus and the small apothecia with no thalline margin. Although growing surrounded by many other genera of lichens, this Caloplaca was found only on Heterodermia.