Caloplaca biatorina (A. Massal.) J. Steiner

      Slightly placodioid crustose thallus, strongly attached to the substrate, appearing as rosettes 3-8 cm in diameter, formed of more or less radiant lobes 0.5-1.5 mm in width, these lobes are more or less convex towards the center and flattened towards the margin, tight against each other, the coloring is bright: red-orange, orange, vermilion, ... practically smooth surface, sometimes a little powdery of whitish towards the margin. Apothecia usually numerous, sessile, 0.5-1 mm in diameter, flat concolorous disc on the thallus, thin and persistent margin, concolorous on the thallus. Asci 50-60 x 12-20 µm according to our measurements, with 8 spores. Spores colorless, very broadly elliptical, polarilocular, 9-16 x 5-9 µm with a septa 1/4 to 1/3 the length of the spore. Paraphyses with a globular and swollen top. C-, K + purple, KC +/- purple, P-. Mountain saxicolous species coming on rocks preferably limestone in the high humid valleys. Rather similar to Xanthoria elegans but the latter species has very convex lobes and well separated from each other.