Distribution: N - Frl (TSB 21344), Piem (TSB 33202), . C- Marc (TSB 23374), Abr (TSB 24555).
Description: Thallus crustose-placodioid, epilithic, forming orbicular rosettes to 8 mm diam., ochraceous yellow to orange, epruinose. Central part of thallus with convex, 0.3-0.6 mm wide areolae which are rarely visible, being covered by crowded apothecia. Marginal lobes highly reduced, strongly convex, 0.3-0.8(-1) mm long and (0.1-)0.2-0.8(-1) mm wide. Upper cortex well developed, (15-)20-80 μm thick, with a 5-30 μm thick orange upper layer, and a hyaline inner layer with irregularly arranged hyphae. Apothecia lecanorine to zeorine, sometimes pseudolecanorine, abundant, 0.2-2.5(-4) mm diam., usually deformed by mutual compression, forming clusters on the lobe bases and areoles, immersed at first, but basally constricted when mature. Disk concave to convex, orange to reddish-orange, epruinose, smooth. Margin in some cases clearly differentiated in an orange, 30- 50 μm thick proper margin and a 40-150(-200) μm thick, usually persistent and often prominent thalline margin. Epithecium (6.5-)10-14 μm thick, brownish-yellow, K+red; hymenium colourless, 50-30(-92) μm tall; ; paraphyses septate, scantly branched, sometimes forked, (1.5-)2-3(-4.5) μm wide at the base, with one or two swollen apical cells (2.5-)3- 7.7(-8.5) μm wide; hypothecium colourless. Asci 8-spored, clavate, Teloschistes-type. Ascospores 1-septate, polarilocular, hyaline, narrowly ellipsoid, (9-)11-14.5(-18.5) x (4-)5.8-6.5(-7.5) μm, the septum (1.5-)3.4-4.5(-5) μm thick. Photobiont chlorococcoid. Spot tests: thallus and apothecia K+red, C-, KC-, P-. Chemistry: thallus and apothecia with parietin (major), fallacinal, emodin, teloschistin and parietinic acid (minor), corresponding with chemosyndrome A of Søchting (1997).
Note: on both calcareous and siliceous rocks, mostly above the submediterranean belt. The greatest majority of samples filed under this name proved to belong to C. pusilla; Italian material still needs revision.