Lecanora concolor Ramond

      Thallus crustose, somewhat placodioid, forming rosettes 5-8 cm in diameter firmly attached to the substrate, areolate in the center and lobed at the margin, straw-yellow, yellowish, pale yellowish-green, yellowish-grey. Lecanorine apothecia, 1-5 mm in diameter, scattered throughout the thallus or in small clusters, flat to convex disc, pale greenish-brown, yellowish-brown, persistent margin +/- crenate. Ascospores simple, hyaline, elliptic, 8-14 x 5-8 µm. Photobiont: chlorococcoid. Thallus: C-, K- or K+/- yellow-brown, KC+ pale yellow, P-. Mountain or alpine species, occurring on the vertical faces of siliceous rocks above the tree line.