Mycelium 1.5-3 µm diam., hyaline, septate, branched, thin-walled, ramifying through the host tissues. Anamorph: conidiomata stromatic, initially covered by a thin layer under which the conidia develop, which breaks up and falls off to expose the conidia and conidiophores; (1-) 2-3 (-3.5) mm diam., 1-1.5 mm high, coalescing to 5-7 x 3-4 mm; shiny black, carbonaceous, occasionally with a light dusty brown covering. In sections the conidiomata are composed of an upper dark brown layer 20-50 µm high that comprises the conidiophores; below it is a paler region of angular cells ca 50 µm high that extends down towards the axial strand. Conidiophores septate, pigmented, determinate and branched. Conidiogenous cells 4-5 x 2.5-4 µm, apical, integrated, cupulate, with a continuous outer wall which subsequently breaks apart when the conidia secede. Conidia in short fragmenting basipetal chains of 2-4, 5-7.5 µm diam., dark brown, with a roughened surface of irregular warts, not septate or more rarely 1-septate, without an epispore, gelatinous sheath or appendages, delimited by a single basal septum with schizolytic secession. Teleomorph: not known.