Description: Thallus crustose, episubstratic, continuous to fissured, whitish, pale grey or greenish grey, rarely weakly zoned at margin, delimited by a white prothallus, esorediate. Apothecia rather common, immersed in strongly convex and basally constricted, 0.5-3 mm wide and up to 2(-3) mm high fertile warts, 1(-3) per wart, with a brownish, often white-pruinose disc, and a slightly prominent thalline margin. Epithecium brown, K-; hymenium colourless; paraphyses slender, 1-1.5 µm thick; hypothecium colourless. Asci 1-spored, broadly cylindrical, the apex with a broad ocular chamber, the outer sheath K/I+ blue, otherwise K/I-, Pertusaria-type. Ascospores 1-celled, hyaline, ellipsoid, 220-350 x 50-75 µm, the wall 2-5 µm thick. Pycnidia immersed, black. conidia short-bacilliform, 4-5 x 0.6-1 µm. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-; top of fertile warts and medulla K-, C- KC+ fleeting violet, P+ reddish, UV-; medulla with a strongly bitter taste. Chemistry: picrolichenic acid.
Note: an epiphytic lichen related to L. amara, but regularly fruiting, and most frequent in eu-Mediterranean areas, with a mainly Tyrrhenian distribution in Italy.(Craighero 2010). A DNA study could better clarify its status. It is included in the Italian red list of epiphytic lichens as “Data Deficient” (Nascimbene & al. 2013c).
Erichsen C.F.E. 1936. Pertusariaceae. - In: Dr. L. Rabenhorsts Kryptogamenflora von Deutschland, Österreich und der Schweiz. Bd. IX, Abt. 5, T. 1. Akad. Verlagsges., Leipzig, pp. 321-512, 513-728. - Public Domain