Thallus inconspicuous, not discolouring the bark, non-lichenized. Anamorph: conidiomata sometimes present; pycnidia 60-100 µm diam. Conidia 7-11 × 0.8-1 μm, filiform, ± straight. Teleomorph: ascomata perithecia, (280-) 400-600 × 220-550 µm and 100-150 µm tall, usually elliptical in outline and with a flat border formed by the spreading involucrellum, the ostiole conspicuous, sunken. Involucrellum thick, dark brown, K+ greenish. Interascal tissue of narrow pseudoparaphyses 1.5-2 µm diam., distantly branched, cells 8-15(-18) μm long. Asci 65-85 (-100) × 12-16 (-20) μm, ± cylindrical, very short-stalked, the apex rounded, very thick-walled and fissitunicate with a very conspicuous ocular chamber, 8-spored. Ascospores 15-23 × 5.5-8 (-9) μm, 1-septate (a few old spores occasionally 3-septate), clavate with rounded apices, markedly constricted at the septum, each cell often biguttulate but without a median constriction (except sometimes faintly so in the lower cell), with a distinct gelatinous perispore 2-3 μm thick in water which is divided at the septum.