Aspicilia leprosescens (Sandt.) Motyka

    Thallus crustose, crackled and areolate, granular to squamulous, formed of flat to slightly convex areoles with upturned edges and then resembling squamules, sometimes covered with globose schizidia, this thallus sometimes presents small finely branched slits arranged in a star shape in cases coming onto a horizontal surface. The general coloring is pale gray, grayish, blue-gray, blue-greenish, a little browning at the end, sometimes as if soiled with a greenish, oliveish coating. Hypothallus sometimes large, more or less zoned, greenish-gray, brown-gray, grayish-white. Aspiciloid apothecia generally few in number (but sometimes abundant when conditions are favorable), 1 to 2 (3) per areole, less than 1 mm in diameter, concave, weakly emerging at the end with a rim paler than the thallus. Spores simple, subglobose to broadly elliptical, 14-30 x 7-16 µm. Pycnidia black, conidia slightly curved, 20--25 x 1 µm. C-, K- (rarely +/- yellow on fresh), KC- (rarely +/- yellow on fresh), P-, UV-. Photobiont: Trebouxia. Common but localized nitrophilous species, sometimes coming in large flocks in the well-winded and sunny rocky areas of the supralittoral zone at the level of HHydropunctaria maura generally on the rocks used as perches for birds, also on the top of the walls of harbour structures or surrounding chapels by the sea.

N.B. This species is quite variable depending on where it is located: brownish gray and almost smooth (because it is often abraded) on horizontal surfaces (cement stain appearance), bluish gray, green gray and granular or lumpy on vertical surfaces.

Cf. Aspicilia caesiocinerea which can sometimes venture into the supralittoral zone, also K- but much less smooth due to its more prominent apothecia and areoles.