Pseudocyphellaria gretae

Detailed description

Thallus ± orbicular or in irregular rosettes, 5-10(-18) cm wide, ± loosely attached. Lobes numerous, 0.5-1.5 cm wide, 1-2 cm long, ± convex, thin and rather delicate in texture, overlapping or at least marginally contiguous except for apices, margins crenate-incised, isidiate, uneven, often sinuous or subascendent. Upper surface bright lettuce-green when wet, pale grey-green, buff to yellowish-olive or pinkish when dry, often becoming dark red-brown on storage, apices slightly darkened, brownish ± uniformly to irregularly tomentose, tomentum, white, silky rather delicate and often thin and abraded in older parts, cortex below tomentum smooth to scabrid and ± reticulate-cracked, undulate, wrinkled, never faveolate, isidiate, without soredia, maculae or pseudocyphellae. Isidia small, delicate, granular, flattened, coralloid, marginal, occasionally and rarely laminal in older parts. Medulla white. Photobiont green. Lower surface pale, whitish to pale pinkish-tan centrally, uniformly white- tomentose to margins, tomentum, soft, silky rather short. Pseudocyphellae white, scattered to numerous, tubercular, minute, inapparent, 0.4-0.8 mm diam., central decorticate area very small. Cephalodia internal, often visible as distinct, ± hemispherical swellings on both upper and lower surfaces. Apothecia very rare, sessile to subpedicellate 0.5-2.0 mm diam., disc concave to plane, dark red-brown, shining, epruinose, margins entire, pale flesh-coloured, tomentose. Ascospores biseriate, 1-3-septate, brown, ellipsoid with pointed ends, 25.5-29 × 10.2-13.6 µm.

Chemistry: TLC−, all reactions negative.