Synonyms: Lopadium pezizoideum var. disciforme (Flot.) Körb.; Sporopodium pezizoideum var. disciforme (Flot.) Vain.
Distribution: N - Frl (Tretiach 2004), Ven (Nascimbene 2003b, 2011, Nascimbene & al. 2010, 2013b), TAA (Nascimbene & al. 2007b, 2009, Nimis & al. 2015). S - Cal (Puntillo 1996).
Description: Thallus crustose, episubstratic, areolate-subsquamulose or granulose, the areoles 0.1-0.4 mm wide, sometimes with small, marginal, isidia-like granules, dark brown to green-brown, usually paler at margins. Apothecia lecideine, black, 0.4-1 mm across, sessile and strongly constricted at base, with a markedly concave to flat disc, and a thick, smooth, prominent proper margin. Exciple paraplectenchymatous, of radiating hyphae, dark red-brown in outer part, paler within; epithecium dark brown; hymenium colourless; paraphyses up to 2.5 µm thick in lower part, simple or forked in upper part, the apical cells 4-7 µm wide, with a dark cap; hypothecium brown-black, K-. Asci 1-spored, ellipsoid to clavate-cylindrical, thick-walled, the outer layer K/I+ blue, without a distinct apical dome, with a thin, K/I+ blue zone under the wall. Ascospores strongly muriform, hyaline (overmature spores sometimes pale yellowish brown), oblong-ellipsoid, 70-115 x 20-47 µm. Photobiont chlorococcoid. Spot tests: K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: on bark and epiphytic bryophytes on old conifers, rarely on acid-barked deciduous trees in cold-humid forests; perhaps overlooked in the Alps, but certainly not common. It is included in the Italian red list of epiphytic lichens as “Vulnerable” (Nascimbene & al. 2013c).