Distribution: C - Sar (Tretiach 1997, Zedda & Sipman 2001).
Description: Thallus crustose-subleprose, episubstratic, consisting of extensive patches of 15-25(-30) μm wide, loose (not linked by hyphae), soredia-like granules, thin and continuous to more rarely thick and cracked, dull pale yellow to pale greenish yellow (whitish yellow with age in herbarium), sometimes delimited by an inconspicuous, pale prothallus. Apothecia rare, usually few and scattered, <0.3 mm across, with a usually flat, rounded, yellow or orange, densely lemon-yellow pruinose disc and a hardly visible (often masked by the soredia), soon excluded proper margin. Proper exciple poorly developed; epithecium and hymenium interspersed with granules dissolving in K and later recrystallizing; hymenium colourless, 20-38(-45) µm high, I+ blue; pseudoparaphyses branched and anastomosing, intricately interwoven in a gelatinous matrix, the apical cells not swollen; hypothecium colourless, of densely interwoven hyphae. Asci 8-spored, clavate, the inner wall extending to form a K/I+ blue papilla. Ascospores (0-)1-3-septate, hyaline, ellipsoid to shortly elongate, (8-)10-13(-15) x 2.7-3.5 µm. Photobiont chlorococcoid, the cells sparse and scattered, densely surrounded by hyphae. Spot tests: K-, C-, KC-, P-, UV+ dull to bright orange. Chemistry: rhizocarpic acid, plus an unknown substance.
Note: a mainly western species in Europe found on bark and lignum in very humid, open forests: probably overlooked, being often sterile, but certainly rare in Italy, and restricted to warm-humid areas. Both Italian specimens were collected on Juniperus. The species is included in the Italian red list of epiphytic lichens as “Endangered” (Nascimbene & al. 2013c).
Growth form: Leprose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)