Description (as Hafellia parastata, p. 86), emended
Thallus thin, light-gray, sometimes with a brownish tinge, continuous or becoming rimose-areolate and plane, or areolate and finely verrucose; areolae to 0.80-2.40 mm wide; verrucae 0.15-0.30 mm diam., mat. Thallus edge determinate, sometimes limited by a narrow black entire hypothallus. Apothecia frequent but rarely contiguous, sessile, to 0.65-1.40 mm diam., largest sometimes slightly lobed; disk dark brown (lighter when wet) more rarely black, plane or becoming slightly convex; margin black, entire, ca. 0.10 mm wide, partly excluded in convex apothecia; exciple 40-90 ,m wide laterally, 80-140 um below, dark reddish-brown throughout, or inner lateral 10-20 ,m less pigmented, 40-130 ,m deep below hypothecium, merging with more lightly pigmented stipe in medial section, marginal cells 4.0-5.5 μm wide; hypothecium dark-brown, 10-20 um deep; hymenium 130-160 μm high, richly inspersed with oil droplets; paraphyses filaments 1.5-2.5 μm wide, branched near apices, apical cells to 3.0-4.5 μm wide, not or scarcely pigmented, immersed in dispersed pigment to form a very light red-brown highly gelatinized epithecium. Asci 90-120 x 35-55 μm, 6-8 spored; ascospores callispora-type, consistently 2-celled, 30.0-(35.1-36.0)-41.1, 35.5 x 18.2, 15.7-(18.0-18.4)-20.8 μm, broadly and bluntly ellipsoid, + mucronate, septum faint, torus present in some older spores, lightly pigmented, walls not pitted, longer spores curved. Pycnidia not found.
Chemistry. Thallus K+ yellow, C-, P- or P+ faint yellow, crystals in cortex and medulla, atranorin and diploicin present.
Substrate and Habitat. Corticolous on hardwood trees.