in Nimis & Poelt, Studia Geobot., 7, suppl. 1: 67, 1987.
Distribution: N - Piem (TSB 34633). C - Tosc, Sar (Monte 1993, Rizzi & al. 2011, Giordani & al. 2013). S - Camp (Nimis & Tretiach 2004), Si (Nimis & al. 1996b, Ottonello & Romano 1997).
Description: Thallus crustose, developing inside the somewhat thickened areoles of silicicolous Circinaria-species, inapparent. Apothecia orange, mostly gathered in small clusters, rounded to very irregular in outline, up to 0.5 mm across, with a flat, orange disc, and an initially prominent and rather thick, orange or orange-red margin which sometimes tends to disappear at maturity. Thaline exciple developed only at the base of the apothecia, corticate, the cortex paraplectenchymatous but poorly differentiated, the medulla rich in algae; proper exciple thin, of strongly adglutinated, radially expanded cells; epithecium orange, K+ red; hymenum colourless, 50-70 μm high; paraphyses 1.5-2 μm thick at base, becoming progressively thicker upwards, the apical cells strongly swollen, to 5 μm wide; hypothecium colourless. Asci 8-spored, clavate, Teloschistes-type. Ascospores 1-septate, polarilocular, hyaline, ellipsoid to almost fusiform, 12-15 x 5-5.5 μm, the septum 3-4.5 μm thick. Photobiont chlorococcoid. Spot tests: apothecia K+ red. Chemistry: apothecia with unidentified anthraquinones.
Note: on south-facing, vertical surfaces of basic siliceous rocks which are, albeit seldom, wetted by water seepage after rain, often found near Peltula-stands (the host being mostly sterile), but somehow less bound to periodical seepage of liquid water; fairly common above the south-facing doors of Sardinian basaltic Nuraghes, and also found in dry-continental Alpine valleys.
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
On otherwise dry surfaces with short periods of water seepage after rain