Pannaria allorhiza

Detailed description

Thallus rosette-forming, lobate, without a prothallus, closely attached, to 12 cm diam. Lobes laciniate-incised, ±discrete at margins, 2-5 mm wide, becoming crowded, imbricate, ± confluent at centre, margins entire, waxy, slightly notched or incised, thickened, conspicuously inrolled, often also ± subascendent, ± isidiate centrally. Upper surface distinctly fibrous and sometimes areolate-scabrid in patches, matt, smooth or shining, when wet, pale greenish-grey or yellowish-buff when dry, not pruinose or tomentose. Isidia gnarled-glomerulate or lobulate, mainly marginal, not developed at lobe apices, often dense centrally, 1-3 mm tall, concolorous with thallus, or often paler and with black spots or patches at apices, ± uniformly corticate. Cephalodia rather rare, on lower surface, globose-glomerulate, often clustered, placodioid, pale grey, smooth, wrinkled, 1-3 mm diam., at lobe margins and towards centre. Lower surface pale buff, darker centrally, with a fine to thick buff tomentum to lobe margins, pale buff or whitish, simple rhizines moderately thickly developed centrally, to 2 mm long. Apothecia numerous centrally, often densely crowded and contorted through mutual pressure, 1-5 mm diam., margins thick, corrugate or granular below, concolorous with thallus, often inflexed, not isidiate, striate-contorted, disc pale red-brown to rarely dark brown or pale yellow- brown, plane and smooth at first, becoming contorted-convolute with age, occasionally centrally fissured or etched, rarely with small thalline lobules, matt, epruinose. Ascospores ellipsoid 15-22 × 11-12 µm.

Chemistry: Vicanicin and (±) allorhizin.