Distribution: N - Emil (Gasparo & Tretiach 1996, Tretiach 1997, Fariselli & al. 2020). C - Marc (Frati & Brunialti 2006, Panepinto & Tretiach 2014), Umb (Ravera & al. 2006b, Ravera & Puntillo 2014), Mol (Paoli & al. 2011). S - Camp (Ravera & al. 2019a), Pugl (Nimis & Tretiach 1999), Bas (Paoli & al. 2006), Cal (Tretiach 1997, Puntillo 1996, Aragón & Martínez 2002, Ravera & Puntillo 2014), Si (Panepinto & Tretiach 2014).
Description: Thallus crustose, episubstratic, consisting of whitish to pale grey, globose to branched-coralloid, c. 0.07-0.2 mm wide, blastidia-like granules. Apothecia lecanorine, round, slightly constricted at base, 0.3-0.8 mm across, with a slightly concave to finally convex, yellow-pruinose disc, and a slightly crenulated margin which is yellow or grey in outer part, yellow in inner part. Epithecium yellowish, inspersed with dark yellow granules, 5-10 µm high; hymenium colourless, 50-70 µm high, I+ dark blue; paraphyses mostly simple, 2-3 µm thick, the apical cells 3-4 µm wide; hypothecium colourless. Asci 8-spored, clavate, with an apical dome which is I+ blue only in the internal, lower part, interrupted in the centre by a a paler blue strip, Candelaria-type. Ascospores 1-celled (rarely a few 1-septate), hyaline, ellipsoid, straight or slightly curved, 13-18 x 4-6 µm. Photobiont chlorococcoid. Spot tests: thallus and apothecia K-, C-, KC-, P-. Chemistry: thallus without lichen substances; apothecia with calycin, pulvinic acid and pulvinic dilactone.
Note: a recently-described a mild-temperate lichen which is certainly more widespread in Italy, especially on wayside trees in small settlements. The species, which is easily overlooked being almost always sterile, is included in the Italian red list of epiphytic lichens as “Data Deficient” (Nascimbene & al. 2013c).
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by isidia, or isidia-like structures (e.g. schizidia)