Distribution: N - TAA, Piem (Isocrono & al. 2003), VA (Piervittori & Isocrono 1999). S - Camp (Aprile & al. 2002), Cal (Puntillo 1996), Si (Grillo & Caniglia 2004).
Description: Thallus crustose, areolate-placodioid, bright yellow to (rarely) greenish yellow in shade-forms, matt, forming rosettes to 4 cm across. Lobes 0.5-1 mm wide and long, crenate, plane; central areoles irregular in shape, c. 1 mm wide, contiguous, flat to subconvex, separated by deep fissures. Upper cortex 35-50 µm thick, opaque, with more or less perpendicular hyphae; algal layer continuous; medulla white, 135-170 µm thick, with crystals dissolving in K. Apothecia to 10 per areole, lecanorine, first punctiform and immersed, then slightly expanded, 0.1-0.3 mm across, with a yellowish brown, round to irregular, plane to slightly concave disc and a thin, often indistinct margin. Excipulum indistinct or to 15 µm wide; epithecium yellowish green to yellowish brown; hymenium colourless, 100-120 µm high; paraphyses 2-2.5 µm thick, the apices hardly swollen. Asci >100-spored, clavate, the apical dome conspicuous, K/I-. Ascospores 1-celled, hyaline, globose to subglobose, 2-4(-5.5) x 2-3(-4) µm. Photobiont chlorococcoid. Spot tests: upper cortex and medulla K-, C-, KC-, P-. Chemistry: rhizocarpic acid.
Note: a species of dry-continental areas found on basic siliceous rocks, often on steeply inclined to underhanging surfaces near the ground, in dry grasslands, both in dry Mediterranean areas and in continental Alpine valleys below the subalpine belt.
Growth form: Crustose placodiomorph
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
Subcontinental: restricted to areas with a dry-subcontinental climate (e.g. dry Alpine valleys, parts of Mediterranean Italy)