Caloplaca nubigena (Kremp.) Dalla Torre & Sarnth. var. nubigena
Die Flechten von Tirol: 184, 1902. Basionym: Callopisma ochraceum var. nubigenum Kremp. - Denkschr. bot. Ges. Regensurg, 4, 2: 163, 1861.
Synonyms: Blastenia nubigena (Kremp.) Müll. Arg.
Distribution: N - Frl, Ven (Tomaselli & al. 2006), TAA. C - Marc (Nimis & Tretiach 1999), Laz (Nimis & Tretiach 2004), Abr (Recchia & Villa 1996, Nimis & Tretiach 1999), Mol (TSB 32589).
Description: Thallus crustose, endosubstratic or very thinly episubstratic, ochracheous yellow to orange, continuous in endolithic forms to rimose in epilithic forms, usually rather well-delimited, forming well-delimited, more or less orbicular patches on the thalli of Clauzadea immersa. Apothecia 0.2-0.5(-1) mm across, at least at the beginning immersed in pits of the rocks or (in epilithic forms) immersed in the thallus, with a dark orange, usually flat disc, and a slightly paler, often finally excluded proper margin, without thalline margin. Epithecium orange-brown, K+ red; hymenium and hypothecium colourless. Asci 8-spored, clavate, Teloschistes-type. Ascospores 1-septate, polarilocular, hyaline, ellipsoid, 9-16 x 3-6 µm, the septum 2-4 µm thick. Photobiont chlorococcoid. Spot tests: thallus and apothecia K+ red, C-, KC-, P-. Chemistry: thallus and apothecia with unidentified anthraquinones.
Note: on calcareous rocks in upland areas, often near summits. Similar to C. coccinea, but differing in morphology, thallus colour, altitudinal distribution (not restricted to above treeline) and in its parasitism on Clauzadea immersa.