Bracted sulphur lichen

Appearance

Thallus: 1-2 cm diam., crustose to squamulose, golden-yellow to yellowish grey, sparingly pruinose, of dispersed or ± contiguous groups of ± convex areoles, the margin not or indistinctly lobed. Lobes scarcely longer than broad, the centre strongly scaly and warty, often ± overlapping and forming irregular clusters, occasionally becoming detached as schizidia. Photobiont chlorococcoid.
Anamorph: not known.
Teleomorph: ascomata apothecia, often present, 0.5-1(-1.2) mm diam., at first concave with a thalline exciple, becoming convex with a ± excluded margin, the disc at first yellow but becoming orange-brown when mature, contrasting with paler thallus. Asci clavate, the upper part with a thickened wall and a strongly blueing outer layer, 8-spored. Ascospores 9-13 × 4-7 μm, broadly ellipsoidal, aseptate, hyaline, without a gelatinous sheath or appendages.
Chemistry: thallus K+ purple (parietin and its precursor emodin), UV± salmon-orange (physcion), small amount of fallacinol and fallacinal (trace) are present, apothecia K+ purple (physcion).