Gyrographa gyrocarpa (Flot.) Ertz & Tehler = Opegrapha gyrocarpa Flot.

    Thallus crustose, sometimes mosaic-forming, leprose, granular, moderately thick, more or less cracked, brown-yellow, brown-red, rusty, brown-pink, brown-orange, brown-chocolate, etc. with areas paler, pinkish, tinged orange or yellow, margin delimited by a black prothallus, mainly visible in case of contact with other species, covered with soralia, up to 1.5 mm diam., lemon-yellow, yellowish, yellow-orange, ochre-yellow, grey-pinkish, in some cases confluent and then generating a thick verrucose matt. Thallus often sterile but sometimes with small scattered lirellae, more or less gyrose or in piles and closed from below, 0.5-1 mm long, black. Ascospores elongate, ellipsoid, 3-septate, 18-25 x 3-5 µm. Thallus: K+ yellow, yellow-orange, soralia: C+ red, KC+ fleeting red, K- or K+ greenish-yellow, P-, UV+ pale yellow. Not especially maritime, frequent on damp vertical walls of shaded siliceous rocks and even more frequeltly on old walls.

_ Not to be confused with some morphs of Belonia nidarosiensis which are C- and may well coexist.

_ Most often this species is leaving with other close species easily mistaken  like Gyrographa (Opegrapha) saxigena of which the thallus is more dark-brown, without soredia and Enterographa zonata that is sorediate, soredia lilac or pale, C-.