Distribution: C - Sar (Giralt & Matzer 1994, Rambold & al. 1994).
Description: Thallus crustose, continuous, smooth, brownish to ochre-coloured. Apothecia lecideine, adnate to sessile, up to 1 mm across, with a concave to slightly convex, black disc, and a thick, persistent proper margin. Proper exciple 40-50(-70) μm wide laterally, aethalea-type, the dark outer part with hyphae with swollen cells. the paler inner part with hyphae similar in structure and orientation to the paraphyses, with crystals visible under polarized light, which react K+ yellow; hymenium colourless, 60-80 μm high, not inspersed with oil droplets; paraphyses capitate, the apical cells up to 6 µm wide, with a brown cap; hypothecium pale to dark reddish brown. Asci 8-spored, clavate, Bacidia-type. Ascospores 1-septate, brown with paler spore-ends, ellipsoid, (11-)12-16 x (5-)6-8 μm, Dirinaria-type, the lumina angular when young, becoming rounded when mature (Pachysporaria-type), smooth to microrugulate, the torus not or poorly developed (ontogeny of type B). Conidia bacilliform, 5-6 x c. 1 μm. Spot tests: thallus K-, C-, KC-, P-; proper exciple K+ yellow. Chemistry; proper esxciple with secalonic acid A (major), and an unknown secalonic acid (trace).
Note: a Mediterranean-Atlantic species, restricted to coastal localities with frequent humid, salt-loaden winds, e.g. on Juniperus on sand dunes. It is included as “Critically Endangered” in the Italian red list of epiphytic lichens (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)