Physcia tribacioides  

Thallus irregular in outline, forming radiating patches or extensive streaks, lobate, lobes rather short, mostly 0.5-1.5 mm wide, closely appressed, often corrugated, crowded and usually ± overlapping, marginal lobes usually with distinctly flared and crenately incised apices, lacking cilia. Thallus pale grey when dry, matt or slightly glossy, not pruinose, pseudocyphellae absent or rare. Soralia to 1.2 mm diam, mostly laminal, strongly convex, hemispherical, often confluent, ± white to pale grey when dry, rarely apical and capitate on short side lobes. Undersurface of thallus ± white to pale brown-white, rhizines rather sparse, simple, pale to mid brown. Lower cortex composed of pseudoparenchymatous tissue with cells 4-7 μm diam. Cortex and medulla containing atranorin, K+ yellow.
Anamorph: not known.
Teleomorph: ascomata rarely produced; apothecia 0.7-1.6 mm diam, very rarely produced, laminal, sessile or short-stalked, shallowly to deeply cupulate, surrounded by a well-developed thalline margin that lacks rhizines. Disc red-brown when fresh, not pruinose, with an orange-brown epithecium produced by encrustations around the paraphysis tips. Hymenium and hypothecium hyaline. Interascal tissue of simple or apically branched paraphyses 1.5-2 μm diam, the tips irregular and usually slightly clavate.  Asci 50 x 20 μm, clavate to cylindric-clavate, very thick-walled in the apical region with an apical dome ± evenly blueing in iodine and a colourless apical cushion, surrounded by a J+ blue gelatinous outer layer, 8-spored. Ascospores arranged biseriately, 18-19.5 (-22) × 7-9.5 (-11) μm, ellipsoidal to fabiform, the apices rounded, with a ± median distoseptum, dark brown, smooth, thick-walled especially at the apices, without a gelatinous sheath or appendages.