Distribution: N - Frl, Ven (Nascimbene & Caniglia 1997, Caniglia & al. 1999, Brackel 2013), TAA, Lomb, Piem (Isocrono & al. 2004, Hafellner & al. 2004), VA (Piervittori & Isocrono 1999, Piervittori & al. 2001). C - Tosc (Vezda Lich. Rar. Exs. 172), Marc (Nimis & Tretiach 1999), Abr (Gheza & al. 2021, Di Nuzzo & al. 2021).
Description: Thallus crustose-placodioid, episubstratic, yellow to orange-yellow, sometimes yellowish-white-pruinose, with (sometimes poorly developed) radiating marginal lobes, the centre verrucose-areolate, forming orbicular to irregular, to 3-4 cm wide, often confluent rosettes. Lobes 0.5-1 mm broad and to 3 mm long, flattened, contiguous, radiating from the central part of thallus, which is densely covered in flattened, often elongate and lobe-like schizidia. Apothecia rare, lecanorine, sessile, 0.5-1.2 mm across, with an orange to brownish-orange, flat, smooth disc, and a thin, orange-yellow margin which at maturity separates into an internal, darker and thinner proper margin, and an external, paler thalline margin. Epithecium K+ red; hymenium colourless, 60-70 µm thick. Asci 8-spored, clavate, Teloschistes-type. Ascospores 1-celled, hyaline, ovoid to slightly pyriform, thin-walled, 9-12 x 3.5-5 µm. Pycnidia orange-yellow, immersed. Conidia bacilliform. Photobiont chlorococcoid. Spot tests: thallus and apothecia K+ red, C-, KC- P-, UV+ pale orange. Chemistry: thallus and apothecia with fragilin (major), emodin, parietin and other anthraquinones (minor).
Note: on calciferous soil and terricolous mosses in open situations, sometimes in fissures of calcareous rocks, mostly near or above treeline; parasitic of Thalloidima sedifolium when young. The record of Grillo (1998) from the coast of Sicilia, is certainly due to a misidentification.
Growth form: Crustose
Substrata: soil, terricolous mosses, and plant debris