Caloplaca flavovirescens (Wulfen.) Dalla Torre & Sarnth.
Gyalolechia flavovirescens (Wulfen) Sochting, Fröden & Arup
Tallus crustose, usually well delimited, round-shaped when horizontal, to 15 cm diam., sometimes rather thin with the subjacent substratum visible in some sections, faintly granular but most often rather thick in case of horizontal substratum, cracked-areolate, irregular angular areoles, dull green-yellow, yellow-lemon when moist, dull orange-grey when dry, more grey-brownish when horizontal and dusty, hypothallus very thin to transparent, paler or whitish or blackish but then often distinct through contact with neighbouring species. Apothecia numerous, distributed all over thallus surface, up to the prothallus, 0.5-1 mm diam., disc plane, soon later convex, more or less dark orange, brown-orange when dry, bright orange when moist, exciple conspicuous, paler. Ascospores ellipsoid, polarilocular, 1-septate, 15-20 x 6-10 µm, septum to 1/3-1/2 of the length of the ascospore. Photobiont: chlorococcoid. All parts K+ purple. Distributed from xeric supralittoral zone to aerohaline zone and even inland, in principle on calcareous rocks, but in our prospecting area rather frequent on siliceous stones of walls, maritime or inland buildings, provided that cement is subjected to leaching; also frequent on flat surfaces at the top of walls and on bridges parapets (and then the thallus mostly is grey-brown due to dust and mud spray). See Caloplaca dalmatica of which the thallus is not yellow-greenish and characterized by deep black cracks, z-shaped, and mainly growing on rocks and calcareous stones of walls. See also some forms of Protoblastenia rupestris of which apothecia are markedly convex and exciple hardly visible.