Anamorph: conidiomata mostly on the abaxial surfaces of leaves, 120–200 × 80–160 μm, elliptical to almost circular in surface view, mid-brown, opening mechanism not observed. Conidiomata subcuticular, 30–60 μm thick, upper wall somewhat convex, 8–10 μm thick, consisting of a thin layer of blackened fungal tissue below the host cuticle, sitting on a flat layer of tanned host epidermal cells; subhymenium hyaline, up to c. 10 μm thick. Conidiogenous cells hyaline, ±cylindrical but tapered towards the apex, 9–14 × 2–3 μm, sympodially holoblastically proliferating, up to 4 conidia being attached to the conidiogenous cell before secession. Conidia hyaline, cylindrical, 5–7 × c. 1 μm, apparently spermatial in function.
Teleomorph: ascomata apparently developing directly from the conidiomata. In surface view: ascomata elliptical, (0·35–) 0·5–0·9 × (0·25–) 0·35–0·5 mm, significantly raising the substratum surface, opening by a longitudinal split extending about 7/8 the length of the ascoma. Clypeus black, shining, sometimes with a paler patch at each end of the split; lips inconspicuous, perimeter line present but poorly defined. In median vertical section: ascomata completely subcuticular; upper wall ±semicircular (lips closed), lower wall ± flat. Clypeus 65–100 μm thick in the central portion, thinning to 20–40 μm at the edges of the ascoma, consisting of an outer layer of host cuticle and an inner layer of brown textura globulosa, whose intercellular spaces are invaded by dark brown fungal material; lips hyaline, 5–10 μm thick; basal wall poorly developed, consisting of a thin dark brown layer of textura globulosa beneath and invading the epidermal and hypodermal cells, in the central portion of the ascoma only; outer part of basal wall consisting only of tanned epidermal cells, but a small blackened area at the junction of the upper and basal walls is sometimes present, showing on the surface as a black perimeter line; subhymenium 6–10 μm thick, of ill-defined textura intricata. Hymenium: interascal tissue composed of paraphyses 80–115 μm, hyaline, 3- to 5-septate, unbranched, the tips irregularly swollen and sometimes slightly recurved, not gelatinised. Asci ripening sequentially, 75–110 (–130) × 15–17 μm, cylindric-saccate, thin-walled, apex obtuse, without apical thickening, dehiscing by means of a small apical crack, 8-spored. Ascospores borne in a fascicle, sometimes slightly helically coiled, cylindrical, tapering towards the base, 55–70 (–100) × 2–3·5 μm, hyaline, aseptate, covered in a gelatinous sheath 2–3 μm thick.