Distribution: C - Tosc (Benesperi & al. 2013). S - Si (Llop 2002).
Description: Thallus crustose-verruculose, episubstratic, grey-green. Cortex paraplectenchymatous, inspersed with minute crystals dissolving in K but not in N. Apothecia lecideine, yellowish orange to reddish orange, becoming darker with age, (0.3-)0.4-1(-1.2) mm across, with a flat to slightly convex disc, and a raised, initially white-pruinose proper margin. Proper exciple prosoplectenchymatous, with oblong, 4-10 x 2.5-4 µm terminal cells, and abundant crystals dissolving in N but not in K: epithecium 3-7 µm high, with minute, colourless crystals dissolving in N but not in K; hymenium colourless, 60-70(-75) high; paraphyses simple or forked in upper part, adglutinated, c. 1 µm thick at mid-level, the apical cells slightly swollen, up to to 2.5-3 µm wide; hypothecium colourless to straw-coloured, K+ intensifying ye11ow. Asci 8-spored, cylindrical-clavate, surrounded by a gelatinous I+ blue coat, with a well-developed I+ blue tholus, a I+ darker blue tube and a well-developed ocular chamber, Bacidia-type. Ascospores (3-)5-7-septate, hyaline, needle-like, straight, (30-)36-52(-59) x 2-2.8(-3) µm. Pycnidia immersed, yellowish brown. Conidia simple, filiform, curved, 10-21 x 0.5-0.8 µm. Photobiont chlorococcoid. Spot tests: thallus K- or K+ yellow-brown, KC-, C-, P-. Chemistry: thallus with atranorin, usually in low amounts; apothecia with the rubella-orange pigment.
Note: a recently-described, probably Mediterranean-Atlantic species related to B. fraxinea and B. rubella, but restricted to coastal, humid situations on littoral shrubs, especially Juniperus. See also note on B. fraxinea. The species is included in the Italian red list of epiphytic lichens as “Endangered” (Nascimbene & al. 2013c).
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)