Caloplaca verruculifera (Vain.) Zahlbr.
Thallus in larges colonies, rosette-shaped, to 5-10 cm diam., made of lobes, 6-8 mm long, 1 mm wide, swollen, branched at margin, yellow-lemon, yellow-orange, center areolate, covered with broadly globose dull green-yellowish isidia, excluded with age, revealing the powdered greenish substratum (more or less horseshoe-shaped or aureole like). Apothecia very rare, disc flat, yellow-orange. Ascospores polarilocular, narrowly ellipsoid, 10-15 x 5-6 µm, 1-septate, septum 1-3 µm. Photobiont : trebouxioide. All parts K+ purple. Rare, on nutrient-rich rocks of the supralittoral zone and notably on bird-perching rocks.*