Thallus orbicular to spreading, 2-5(-10) cm diam., closely attached. Lobes sublinear, 1-2(-3) mm wide, ± subdichotomously branching towards apices, margins black, shining, sparsely ciliate. Upper surface plane, or uneven, ± corrugate or very shallowly faveolate, matt or shining, with a faint reticulum of white lines (×10 lens) on some lobes, often at apices, greenish-grey to whitish, lobe ends often pruinose, isidiate. Isidia simple, terete, delicate, brown-tipped, 0.3 mm tall, rather slender, often crowded, laminal and marginal. Lower surface black, olive-brownish at margins, shining, wrinkled-papillate. Rhizines black, long, simple to squarrosely branched. Apothecia not seen. Chemistry: Cortex K+ yellow; medulla K-, C-, KC-, Pd+ red. Fumarprotocetraric acid and atranorin.