Lecanora rupicola (L.) Zahlbr. subsp. subplanata (Nyl.) Leuckert & Poelt forme maritime grise.

     Thallus crustose, well defined, typically circular, up to 10 cm in diameter, surface strongly cracked, more or less rough and bumpy, grayish, gray, prothallus concolorous, wide and scarred. Apothecia more or less numerous, immersed in the thallus, and very slightly protruding, 1 to 2 mm in diameter, flat discs, concolorous to the thallus (unless parasitized!), margin sometimes with an irregular shape, which may be a little prominent and appear on the thallus somewhat raised, whitish or paler, entire to crenate. Spores simple, elliptical, 9-15 x x 5.5-7 µm according to the literature Photobiont: green algae. Thallus: C- most often, or rarely C+ orange, K+ yellow, KC+/- orange or yellow, P+/- yellow; disc of apothecia: C- or C+ orange (Very variable, but also because the commercial bleach solution usually used contains soda (NaOH)), Species with strong coastal affinities, coming on siliceous rocks not too acidic and sheltered, common in the xeric supralittoral zone where it can form large colonies, also frequent in the aerohaline zone.

N.B. Very frequently parasitized by Arthonia varians.