Trapelia placodioides Coppins & P. James
Thallus crustose, closely appressed, to 5-10 cm across, cracked in the center, margin placodioid, areoles forming, with a rough surface, 0.2-0.5 mm diam., whitish, cream, white-pink, pinkish, white-orange, ochre-yellow, sometimes with orange patches on iron rich rocks, with scattered and seldom numerous soralia, green-yellowish to cream or cream-rusty or even ochre-yellow in older specimen. Apothecia very rare, 0.2-0.8 mm diam., disc flat, brown-red to brown-blackish, exciple thin, soon excluded. Photobiont: chlorococcoid. Thallus : C+ red, K-, KC+/- red, Pd-. Rather rare in our prospection area, on mine spoil heaps and siliceous rocks not too acidic, most often on iron-rich rocks and notably on spoil slates.*
