Distribution: C - Tosc (TSB 35226), Sar (Nimis & Poelt 1987). S - Camp (Brunialti & al. 2013, Ravera & Brunialti 2013), Pugl (Nimis & Tretiach 1999).
Description: Thallus crustose, smooth, white, pale grey or pale brown, without a distinct prothallus, sometimes with an orange pruina. Apothecia lirelliform, simple or usually branched, 0.8-2.2(-2.8) x 0.2-0.4 mm, sessile or semi immersed, black, with an initially slit-like, later expanded disc, the margin and sometimes the disc often covered with a rusty orange pruina. Proper exciple black, carbonized, extending below the hymenium, 20-30 μm thick laterally, 40-50 μm thick at base, K+ magenta-red; epithecium red-brown, 10-17 µm high; hymenium colourless, 50-65 µm high, I+ blue in upper part, I+ red in lower part; paraphysoids branched and anastomosing, c. 1 µm thick, the apical cells hardly swollen; subhymenium red-brown, 17-35 µm high, I+ pale blue; hypothecium black, carbonized. Asci 8-spored, clavate, the inner layer of endoascus amyloid in upper part, with a ring visible around a small ocular chamber, Varia-type. Ascospores 3-septate, hyaline, ellipsoid with a slightly pointed end, (11-)14-20(-22) x 3-5 µm, with a poorly visible, thin gelatinous perispore. Pycnidia semi-immersed, black, surrounded by a rusty orange pruina. Conidia simple or often 2(-3)-septate, hyaline, straight or slightly curved, 12-23 x 0.8-2 µm. Photobiont trentepohlioid. Spot tests: thallus K- or K+ magenta-red in the orange-pruinose parts, C-, KC-, P-; orange pruina on apothecia and pycnidia K+ magenta-red. Chemistry: thallus without lichen substances, 2 unidentified substances in the orange pruina.
Note: a Mediterranean-Atlantic species found on on the smooth bark of evergreen broad-leaved trees and shrubs, more rarely on lignum. It was listed under the dubious records by Nimis (1993: 464), but material from Sardegna was revised by Egea & Torrente (TSB), and the identification by Nimis & Poelt (1987) proved to be correct. Specimens from Toscana and Puglia comply with those from Sardegna. The species is included in the Italian red list of epiphytic lichens as “Endangered” (Nascimbene & al. 2013c).
Growth form: Crustose
Reproductive strategy: mainly sexual
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)