Thallus formed of large squamules with rounded ends 1-3 mm long, more or less sessile and tight against each other, upper surface smooth, brown, light brown, chestnut, reddish-brown if dry, greenish-brown or glaucous brown if wet, powdered with whitish especially towards the margin which appears as frosted. Apothecia sometimes absent or few in number and poorly formed, one per squamule, reddish-brown, reddish. Spores greater than 100 per ascus, single, colorless, 4-6 x 2-2.5 µm. No significant color reactions. Photobiont: green algae. Species occurring on dry and sunny limestone rocks in the Mediterranean region. N.B. Very variable species of which many varieties have been described (linked by intermediaries!), In particular var. glaucocarpa and var. cervina more mountainous. These varieties being very variously interpreted by the authors, we will stay here in the broad sense.