Peltula euploca (Ach.) Poelt.

     Foliose thallus formed of a single cup-shaped squamule, 10-15 mm in diameter, attached by its center, upturned margin bearing soredia, the union of numerous thalli can form large colonies. Upper surface smooth, olive-green, olive-brown, bronze-green, lower surface pale brown with pink reflections; margin typically bordered by bluish-grey, bluish-black soredia. Apothecia very rare, initially buried in the thallus then on the surface, 0.5-1 mm in diameter. Claved asci with more than 30 spores. Ascospores simple, narrowly elliptical, 6-9 x 3-6 µm. Pycnidia cerebriform, immersed in the thallus, 100-150 µm in diameter, conidia simple, fusiform, 3-4 x 1-1.5 µm. Photobiont: chlorococcus and cyanobacteria. C-, K-, KC-, P-, UV-. Thermophilic and Mediterranean species growing on the vertical faces of slightly acidic siliceous rocks exposed to the sun.