Description: Thallus crustose, episubstratic, very thin to up to 0.3 mm thick, continuous to verruculose-rimose, greenish white, grey-green or bluish grey, minutely granular being completely covered in farinose soredia. Apothecia sessile, biatorine, 0.1-0.3(-0.4) mm across, with a white-pinkish (turning pale yellowish-brown in the herbarium), concave to finally convex disc, and a white, more or less regular, wavy, finally excluded proper margin. Proper exciple cellular, colourless; epithecium colourless; hymenium colourless, 30-50 µm high, I+ blue; paraphyses simple or branched and anastomosing in upper part, 0.5-1 µm thick at base, the apical cells up to 2 µm wide; hypothecium colourless. Asci 8-spored, clavate, with a K/I+ blue apical dome containing a darker blue, tubular ring-structure, and an amyloid coat, Byssoloma-type. Ascospores 1-septate, hyaline, ellipsoid to sole-shaped, sometimes slightly constricted at septum and with unequal cells, 9-15 x 3-6 µm. Pycnidia prominent, whitish, bottle-shaped, with a short neck and a gaping ostiole. Conidia pyriform, 3-4 x 1.3-1.7 µm. Photobiont: chlorococcoid. Spot tests: thallus K-, C-, KC-, P-. Chemistry: usnic and isousnic acids, zeorine, variable amounts of asemone.
Note: a temperate to southern boreal-montane species found on leaves and twigs of conifers (especially Abies in the Alps), but also on evergreen Mediterranean trees and shrubs (e.g. Buxus, Ilex) in very humid situations. F. gyrophorica Sérus., Coppins, Diederich & Scheid. is known from eastern central Europe; North Italian records should be checked against that species. The species is included in the Italian red list of epiphytic lichens as “Near-threatened” (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)