Stromata developing within the bark, 1-2 (-5 ) mm diam., containing 2-6 (-15) ascomata, pustulate, circular to ovoid in outline, pulvinate to conical, sometimes only partially emergent, black, rugose, scattered or confluent in small groups. Ostioles emerging collectively, or separately in large stromata, in many collections not obviously furrowed and hardly projecting beyond the outer layer of the stroma. Inner tissue of the stroma (entostroma) white, sometimes well-developed; often limited by a black line within the wood. Anamorph: conidiomata formed as plurilocular cavities within the stroma, without a well-defined wall, lined with conidiogenous cells. Conidia orange in mass. Teleomorph: ascomata perithecia, 400-600 µm diam. and 600-900 µm tall, ± globose to ovoid but often distorted by pressure from surrounding ascomata, with a short cylindrical neck. Interascal tissue composed of broad, very thin-walled unbranched paraphyses. Asci narrowly clavate, often very long-stalked, the part containing spores (30-) 40-60 (-70) x 6-8 µm, the stalk 60-120 µm long, gradually tapering, thin-walled, not fissitunicate, the apex obtuse to truncate, with a minute apical ring that usually blues in iodine, 8-spored. Ascospores arranged irregularly, 9.5-12 (-15) x 2.5-3 µm, allantoid, pale yellow-brown, aseptate, thin-walled, without an epispore, gelatinous sheath or appendages.