Thallus 5-10(-15) cm diam., spreading, loosely attached, thin, fragile, papery, sometimes in densely compacted, ± caespitose hummocks. Lobes 2-4(-10) mm wide, broad towards periphery, narrow, convolute-complicate centrally, margins rarely entire, sinuous, crisped, ± ascending, ± densely lacerate-incised, becoming phyllidiate, sometimes pubescent. Upper surface matt, minutely pitted or wrinkled, to minutely white-papillate (×10 lens), bright lettuce-green, suffused brownish or dark olive in parts when wet, paler when dry, margins sometimes white-pruinose, phyllidiate. Phyllidia marginal, never laminal, 0.1-0.5 mm wide and tall, irregular, pectinate, ± ascending, often merging into smaller marginal lobes, sinuous, often white-pruinose, or pubescent, often dense centrally. Lower surface pale buff, to mid brown or dark brown centrally, tomentose, tomentum white, rarely dark brown, short, uniform, thin at or near margins, or with a narrow, wrinkled, glabrous marginal zone. Cyphellae round to irregular, 0.05-1.0 mm diam., white, scattered. Apothecia sessile to subpedicellate, sparse to numerous, solitary, to 2-3-confluent, round to contorted through mutual pressure, 0.1-4.0 mm diam., concave at first, soon becoming plane and then convex-undulate, pale red-brown to dark brown or brown- black, margins pale flesh-coloured or whitish (translucent when wet), inflexed at first, thin at maturity and then crenate-striate, often ± denticulate, exciple pale buff or whitish, to corrugate-scabrid or pubescent. Epithecium red-brown, granular, 8-12 µm thick. Hymenium colourless, 50-70 µm tall. Asci clavate. Ascospores biseriate, colourless, elongate-ellipsoid with pointed ends, 1-3-septate, 20-30 × 5-8.3 µm.