Brodoa atrofusca (Schaer.) Goward

    Foliose thallus formed of convex lobes, with rounded, brown ends, 1-2 mm wide, arranged radially in a rosette 2-5 cm in diameter, sometimes thinning from the center and without the appearance of secondary lobes. Upper surface grayish, grayish-brownish, graying and blackening strongly from the center of the thallus; lower surface more or less smooth and without rhizines, brownish to blackish. Apothecia rare, lecanorine, 5-10 mm in diameter, disc dark brown, thin margin entire or slightly crenate. Ascospores simple, hyaline, broadly elliptical, 9-12 x 6-7 µm. Pycnidia very numerous visible in the form of blackish dots. Photobiont: chlorococcoid. Cortex: C-, K+ yellow, KC-, P-; medulla: C-, K-, KC+ red, P+ orange. An uncommon mountain and alpine species that grows on siliceous rocks above the tree line.

_ See Brodoa intestiniformis, which is very similar but less blackish and has secondary lobes and, more importantly, a KC- medulla.