Megalaria grossa (Nyl.) Hafellner

   Thallus crustose deeply embedded in its substrate, thin, smooth to weakly rimose, whitish, grayish-white, whitish-glaucous, whitish-greenish, no prothallus. Apothecia lecideine, non-sessile or very little, black, 0.2-0.3 mm in diameter, thin proper rim disappearing very quickly as soon as the apothecium becomes convex. Ascospores thick-walled, hyaline, oblong, 1-septate with a small constriction at the septum (pharmaceutical capsule appearance), 20-34 x 10-16 µm. Pycnidia black embedded in the thallus, conidia 3-4 x 1.5-2 µm. Photobiont: chlorococcoid with very little orange pigment. C-, K-, KC-, P-, UV-. Uncommon species growing on the bark at the base of the trunks of old hardwood trees in humid and warm forests.