Distribution: N - Piem (TSB 32805), VA (Piervittori & Isocrono 1999, Matteucci & al. 2008c, Puntillo & Puntillo 2009, Watson 2014). C - Abr (Nimis & Tretiach 1999, Puntillo & Puntillo 2009), Sar (Zedda 2002, 2002b, Puntillo & Puntillo 2009, Rizzi & al. 2011, Di Nuzzo & al. 2022). S - Cal (CLU 17604).
Description: Thallus crustose, episubstratic, continuous to usually verrucose, bright yellow-green. Cortex densely inspersed with yellow crystals, the uppermost part with a hyaline layer. Apothecia immersed in 0.5-0.8 mm wide thalline warts, 0.2-0.5 mm across, covered with a black, epruinose mazaedium. Exciple 14-34 µm thick laterally, not or only slightly thickened at base, of intricately interwoven, brown, sclerotized hyphae with thickened walls; hypothecium very thin, poorly pigmented, Asci ellipsoid to pyriform, rupturing at a very early stage, with 2-3 seriate spores. Ascospores at first 1-septate, then submuriform with oblique septa, brown, broadly ellipsoid or irregular in outline, constricted at septa, 17-24 x 13-18 µm, with 2-14 cells. Pycnidia black, confluent. Conidia 1-celled, hyaline, cylindrical or ellipsoid. Photobiont chlrococcoid. Spot tests: thallus K-, C-, KC-, P-. Chemistry: thallus with rhizocarpic acid.
Note: a mainly cool-temperate to southern boreal-montane lichen found on dry, weathered wood (e.g. on fences, wooden poles), but also on bark of old acid-barked trees (especially Quercus); perhaps more widespread in the Alps. It is included in the Italian red list of epiphytic lichens as “Vulnerable” (Nascimbene & al. 2013c).