Thallus to 10 cm diam., crustose, weakly to strongly rimose or irregularly cracked, with an indistinct prothallus. Areoles to 0.5 (-1) mm diam., grey to pale ochre-brown or rust-red due to uptake of iron compounds, often paler and less cracked in shady habitats, matt, angular, ± flat. Soredia and isidia absent. Photobiont chlorococcoid. Anamorph: not reported. Teleomorph: Ascomata apothecia, 700-1200 µm diam., dark brown to black, not pruinose, round or irregular due to compression from surrounding apothecia, partially immersed in the thallus or distinctly raised above, weakly concave to weakly convex, the disc sometimes with an irregular central umbo. Thalline exciple absent, true exciple thick, persistent, sometimes distinctly swollen, dark brown at the rim, inner part sometimes paler brown, K–. Epithecium olive-green to olive-brown, sometimes K± purple-red in patches, sometimes appearing granular from the surface. Hymenium 140-180 µm thick, hyaline to pale brown. Hypothecium red-brown, K–, not clearly differentiated from the exciple. Crystals and granules not present in the apothecia. Interascal tissue of strongly agglutinated pseudoparaphyses, branched and anastomosed, some branched at the tips, the apices hardly swollen. Asci clavate to cylindric-clavate, very thick-walled and fissitunicate (sometimes with multiple layers visible in the apical region), fairly short-stalked, the apex rounded and very strongly thickened but without a clearly defined ocular chamber, the upper part of the tholus staining blue in iodine, 8-spored. Ascospores arranged biseriately, 30-40 × 12-14 (-18) μm, irregularly muriform, usually with 6-7 transverse septa and 1-2 longitudinal septa, quite thick-walled, smooth, persistently hyaline or becoming faintly brown with age, with a swollen gelatinous sheath that tends to break down in KOH. Chemistry: lichen products not detected by TLC.