Caloplaca decipiens (Arnold) Blomb. & Forsell

    Thallus placodioid, composed of radiating contiguous lobes, rosette-shaped, 2-3 cm diam.; lobes tightly appressed, lobe-ends to c. 1 mm wide slightly palmate, convex, conspicuously pruinose, yellow-green, pale brown-yellow in shaded vs yellow-orange in well lit situations; typically with concolourous clusters of granular soredia (isidioids) at lobe margins, notably on small inner lateral lobes at the thallus center which sometimes looks crumpled or necrotic. Apothecia rare, 0.5-1 mm in diameter, disc concave then flat, orange, margin thick, persistent. Asci with 8 spores of 70-80 x 15-25 µm according to our measurements. Spores broadly elliptical, polarilocular with a septum 2-3 µm wide and 1/4 to 1/3 the total length of the spore, 10-15 x 5-8 µm according to the literature, (13)-14-15 x (5)-6-8 µm according to our measurements. Photobiont: trebouxioid. K + purple on thallus and apothecia. Species occurring on the mortar of the walls, the asbestos cement, rarer on the limestone rocks of the seashore. Cf. Candelariella medians with thallus without orange colors or soredia and K-.