Colonies usually discrete in strictly localized areas of the host thallus, more rarely somewhat scattered, dark brown to black and then often somewhat shiny. Mycelium mainly immersed in the upper cortex of the host, composed of pale brown flexuose hyphae. Hyphae 2.5-4 µm diam., thin-walled, smooth-walled, septate, not or slightly constricted at the septa. Anamorph: conidiomata absent. Conidiophores 40-80 (-150) x 7-9 µm, very variable in height, somewhat differentiated from vegetative hyphae, arising singly or in caespitose tufts, straight, unbranched, dark brown, septate, smooth- and thick-walled, constricted at the septa. Conidiogenous cells not clearly differentiated from the conidiophore, terminal, subcylindrical to doliiform, dark brown, with the terminal cells acting in turn as conidiogenous cells. Conidia 18-25 x 7-9 µm, adhering in chains, separating with difficulty, dry, doliiform, dark brown, mostly 1-septate, only slightly constricted at the septum, frequently 1- to 2-guttulate, smooth- and thick-walled. Teleomorph: not known.