Anamorph: conidiomata scattered, superficial, on blackened parts of the sustratum surface, somtimes on a weakly developed brown subiculum, similar in appearance to the ascomata but usually smaller and with a somewhat thinner black external wall which may appear dark brown when wet. Conidiophores in a compact palisade and interspersed with paraphyses, also formed within ascomata, usually in the marginal parts; to 70 µm on length and 2-3 µm diam, cylindrical, ± straight, thin-walled. Conidiogenous cells not differentiated from the conidiophores, the apices irregular and often slightly swollen, proliferating sympodially with old loci visible as slight papillae. Conidia 15-30 x 2-3 µm, cylindric-fusiform, often slightly curved, the apex often rostrate but without cellular appendages, eventually becoming 3-septate, hyaline, thin-walled, without a gelatinous sheath or appendages.
Ascomata to 1200 µm diam and 900 µm tall, black when dry, dark brown to black when wet, with a conspicuous central depression, tearing open with irregular fissures to expose the hymenium. Ascomatal wall 2-layered, the outer wall 10-25 µm thick and composed of thick-walled strongly melanized isodiametric cells 6-10 µm in diam, the inner layer to 160 µm at the base, composed of hyaline thick-walled cartilaginous short-celled tissue. Subhymenium poorly developed. Paraphyses 1.5-2 µmm diam, filiform, unbranched, the apex sometimes slightly swollen. Asci 50-80 x 7-11 µm, cylindric-clavate, short-stalked, thin-walled, the apex obtuse and conspicuously thickened with a pore that blues in iodine, 8-spored. Ascospores arranged biseriately, 8-17 x 3-5 µm, ellipsoidal, often slightly inaequilateral, thin-walled, hyaline, aseptate, without a gelatinous sheath or appendages.