Life habit: lichenized Thallus: crustose, granulose, gelatinous when wet surface: blackish, rough anatomy: ecorticate, paraplectenchymatous photobiont: primary one a chroococcoid cyanobacterium, secondary photobiont absent Ascomata: absent or present, apothecial, laminal on thallus, orbicular, sessile; margin: distinct to prominent, with thalloid rim, evanescent with age ontogeny: hemiangiocarpous, ascogonia arising in a tangle of generative hyphae beneath the thallus surface ascoma anatomy: exciple: yellow, yellowish brown or hyaline; epithecium: brownish yellow asci: prototunicate; walls: thin, nonamyloid; 8-spored ascospores: simple, ellipsoid to broadly ellipsoid, 10-28 x 7-15 micrometer; walls: thin, hyaline Conidiomata: pycnidial, laminal, immersed conidia: ellipsoid, c. 3 x 1 micrometer Secondary metabolites: not detected Geography: in arid, semi-arid to warm temperate regions of the Northern Hemisphere Substrate: on limestone, caliche or calcareous soil. Notes: The genus is most similar to Psorotichia which has a distinctly thinner exciple or lacks an exciple completely. In Porocyphus the ascomata arise beneath pycnidia and the paraphyses are usually more slender.