Thallus filamentous, in rosettes or aggregates, 2-20 mm diam., olive, blackish or greyish (through impregnation of dust), rosettes decaying centrally, leaving arcs or rings, aggregate tufts separating into areolae, to 1 mm tall. Filaments recurved, 1-2 mm long, paired branches with separating tips, tips 10-20(-30) µm, double branches 30-55 µm, basal parts 65-110 µm thick. Basal strand well-developed, hyphae with predominant rectangular branching, cells elongate, angular or rounded. Apothecia lateral, to 0.4 mm diam., disc brown, thalline margin uneven. Hymenium 100-130 µm tall. Hypothecium 10-50 µm thick. Excipulum lacking, supporting tissue developed below hymenium and extending into adjacent thallus. Asci broadly cylindrical or clavate, 70-82(-90) X (10-)14-20 µm, 24- or rarely 16-spored. Ascospores simple, colourless, ellipsoid or almost globose, thick-walled at maturity, 7-11 X 5-8 µm. Paraphyses branched paraphysoids, or distinctly septate true paraphyses, end cells enlarged to 2.5-4 µm. Pycnidia c. 0.2 mm broad. Conidia rod-shaped, 3-4.5 X 1 µm, terminal on long-celled conidiophores.