Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2007. Lichen Flora of the Greater Sonoran Desert Region. Vol 3.

Life habit: saprobic, not lichenized Thallus: sterile mycelium immersed in the substrate Apothecia: dark brown to black, rather robust, 0.5-0.8 mm tall, with a shining stalk often thickened towards the base capitulum: 0.3-0.5 mm in diam., lenticular to almost spherical, with a strongly incurved margin and a minute disc exciple: 45-110 µm thick, well-developed, consisting of hyphae with swollen walls forming a prosoplectenchymatic tissue, inner part hyaline, outer part reddish brown to brown, outer surface covered by a very thin yellowish green pruina and often with longitudinal ridges stalk: short, 0.12-0.16 mm in diam., the central part consisting of irregular, strongly swollen, branched and intertwined hyphae with swollen walls which are moderately branched and intertwined, with lumina 1-1.5 µm in diam., outermost part of stalk reddish brown to brown, reddish parts of the ascomata K+ violet red and H+ slightly intensified red hymenium: dark brown above, 55-80 µm tall, lining the inner surface of the exciple and extending upwards along the inner edge of the exciple; hypothecium: poorly developed asci: cylindrical, 54-65 x 4-4.5 µm, with moderately thickened apex often with a short and blunt canals ascospores: dark brown, simple, fusiform to ellipsoid, 7.5-10 x 4-4.5 µm, smooth under the light microscope Pycnidia: not observed Secondary metabolites: yellow pruina of the ascomata with vulpinic and pinastrinic acids. Substrate and ecology: on dry wood World distribution: USA (Iowa and Texas), Mexico and Dominican Republic Sonoran distribution: Baja California Sur and Sonora. Notes: Mycocalicium calicioides is characterized by its robust ascomata, its strongly constricted exciple edge and its faintly pruinose and rugose capitulum surface. It is quite similar to M. americanum (see above). See Tibell (1987 & 1996) for further details.