Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Life habit: lichenized Thallus: crustose, rimose-areolate, areoles composed of densely aggregated lichenized photobiont colonies, "packets" or "lobes" ±vertically arranged, dying from the base; gelatinous when wet thallus surface: black, rarely gray, usually dull, rarely glossy, plane, usually rough or somewhat farinose thallus anatomy: ecorticate, paraplectenchymatous or densely reticulate, cells small photobionts: primary one is a chroococcoid cyanobacteria, secondary photobiont absent Ascomata: apothecial, immersed to adnate; margin: distinct or indistinct, with the thalloid rim usually separated from the proper exciple by a narrow slit disc: rough or umbonate ontogeny: hemiangiocarpous, ascogones and sparse generative hyphae arising in gelatinous matrix between sterile thallus lobes or packets proper exciple: thin, usually black (but not carbonaceous) or brownish, composed of ±parallel, gelatinized hyphae, epihymenium: brownish black; paraphyses: septate, sparingly branched and anastomosing, apical cells somewhat clavate asci: ±cylindrical or narrow clavate, prototunicate; wall: thin, non-amyloid, 8-spored ascospores: simple, hyaline, ellipsoid, (7.5-)10-13.5 x (5)7-9.5 µm, thin-walled Conidiomata: pycnidial, laminal, immersed, sometimes superimposed, ellipsoid; conidiophores: simple, cells elongated conidia: ellipsoid or bacilliform, 2-3.5 x 1-1.5 µm, acrogenous Secondary metabolites: none detected Geography: Europe, SW North America, Venezuela and southern Yemen Substrate: on various sporadically or periodically moistened rocks. Notes: The peculiar growth form (revealed in cross sections) of Metamelanea with vertical packets or lobes dying from the base, its type of ascoma ontogeny, its umbonate apothecial discs and its distinctly colored true exciple are characteristic.