Fuscoderma amphibolum

Detailed description

Thallus foliose-lobate, loosely attached, corticolous or muscicolous, 6-8(-10) cm diam., without a marginal prothallus. Lobes radiating, convex, sublinear, subimbricate, margins undulate, shallowly incised, sorediate. Upper surface dark bluish-green when wet, glaucous-green to brownish when dry, smooth, glabrous, ± coriaceous to minutely scabrid (×10 lens), margins often strongly white-tomentose, sorediate or not. Soredia marginal, granular to pulverulent or delicate-coralloid, bluish-white. Lower surface uniformly whitish-buff tomentose, margins of lobes often conspicuously thickened. Rhizines brownish or bluish-black in conspicuous, squarrose tufts. Apothecia frequent, prominent, ± central, sessile to subpedicellate, to 1 mm diam., disc orange to red-brown, with a thin, pale margin, plane or concave at first, becoming convex with age, smooth, waxy, epruinose not gyrose-etched. Ascospores fusiform, ellipsoid, ± apiculate at both ends, apiculae c. 5 µm long, 11-16 × 6-7 µm.

Soredia are not constant in the species throughout its known range and are possibly a shade or moisture modification.