Anamorph: conidiomata immersed in living or moribund twigs or small branches, 300–600 μm diam., roughly circular, raising the surface of the bark, with a large irregular opening where the covering layers have split, comprising a cluster of one to several locules separated from each other by a central core. Conidiogenous cells borne on hyaline single-celled occasionally branched conidiophores or directly from the lower wall, 15–35 × 2–3·5 μm, cylindrical but tapering slightly towards the apex, hyaline, proliferating sympodially. Conidia 5–7 × 1–1·5 μm, cylindrical, rounded at both ends, sometimes slightly allantoid, hyaline, aseptate, thin-walled, smooth. Teleomorph: ascomata immersed apothecia, on dead twigs, following the conidiomata; deeply embedded in the substratum, becoming virtually superficial as the covering layers of the substratum peel back, 1.5–5 × 0.6–1 μm when shut, wider when open, narrowly oblong to elliptical, often curved or branched, strongly raising the surface of the substratum, opening by a longitudinal, sometimes branched split; 350–1000 μm deep, with a blackened covering layer 150–250 μm deep in the central region. Interascal tissue of paraphyses 100–130 μm long, filiform, septate, strongly contorted or coiled but not swollen at the apex, covered in a very thin mucous sheath. Asci maturing sequentially, 120–160 × 9–10 μm, narrowly clavate, very long-stalked, thin-walled, with ± acute apices, without circum-apical thickening, 8-spored. Ascospores arranged in a fascicle, not helically coiled, 55–80 × 0·5–1·5 μm, filiform, tapered towards the base, aseptate, sometimes becoming multiseptate, smooth, hyaline, thin-walled, covered in a mucous sheath ca 1 μm thick.