Distribution: N - Emil (Fariselli & al. 2020), Lig (Brunialti & al. 1999). C - Tosc (Benesperi & al. 2007).
Description: Thallus crustose-subsquamulose, heteromerous, 150-250 μm thick, firmly attached, cracked-areolate, sorediate, delimited by a bluish-black prothallus. Squamules pale chestnut brown to pale reddish brown, 0.5-2 mm wide, the marginal ones often larger and elongate, to 3-4 mm wide and long, rounded to slightly irregular in outline, flat to slightly convex, most often contiguous, with slightly ascending, usually paler margins; soralia cream-coloured, at first marginal, later confluent and often covering the whole central part of thallus, with finely granular soredia; lower surface ecorticate, developing on a felt-like, blue-black hypothallus. Upper cortex paraplectenchymatous, 35-40(-60) μm thick; medulla 50-75 μm thick, of intricate hyphae forming a lax plectenchyma, gradually merging into the hypothallus. Apothecia lecanorine, unknown in the mature state. Photobiont cyanobacterial (Nostoc, the cells in clusters). Spot tests: thallus and medulla K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: a mild-temperate species found on bark of ancient deciduous trees in humid woodlands; certainly very rare and endangered in Italy. It is included in the Italian red list of epiphytic lichens as “Vulnerable” (Nascimbene & al. 2013c).