Solenopsora candicans (Dicks.) J. Steiner

    Thallus crustose, tightly appressed, placodioid, composed of lobes, rosette-shaped 3-5 cm diam., slightly cracked and irregular towards the center, radiating lobes towards margins, surface more or less pruinose, chalk-white, tinged glaucous towards margins. Apothecia lecanorine, usually numerous, 1-2 mm diam., immersed at first, turning to sessile with distinct thalline exciple (potentially vanishing when mature), disc flat, then slightly convex, chocolate, dark brown, blackish, sometimes slightly pruinose. Ascospores hyaline, narrowly ellipsoid, 1-septate, 12-20 x 3-4 µm according to literature, 12-17 x 3-4(5) according to our measures. Photobiont: chlorococcoid. Thallus: C-, K-, KC-, Pd+ orange. Thermophilic species, thriving on well exposed calcareous rocks, common in Mediterranean regions. Present although rare in less sunny regions of the Atlantic coasts of France.