Thallus not well delimited, immersed, visible only under the compound microscope as a thin fungal layer with hyphae occasionally associated with chlorococcoid and/or Trentepohlia algae around the ascomata. Anamorph: conidiomata not observed. Teleomorph: stromata absent. Ascomata perithecial, 100–150 (–200) μm diam., mostly circular, well delimited and arising singly, semi-immersed in the substratum with a central ostiole situated in a small depression; dimidiate (flattened) in section, to 65 μm tall. Involucrellum clypeate, dark brown, almost black in water mounts, remaining unchanged after adding K, and not extending into the thallus to form a basal fringe; composed of epidermoid hyphae, the cells becoming ± globose towards the ostiole. True exciple colourless, consisting of a few layers of isodiametric cells forming a pseudoparenchymatous tissue and continuing below the ascoma. Interascal tissue composed of richly branched cellular pseudoparaphyses ca 1.5 μm diam. Hymenial gel blueish after IKI. Asci (30–) 35–50 (–55) x 9–12 μm, cylindrical to broadly clavate, geniculate at the base, functionally bitunicate, the endotunica with a broad truncat apex, mostly 8-spored. Ascospores arranged in a single fascicle, (27–) 34–40 x 1.5–2.5 μm, slightly twisted, narrowly fusiform, arcuate to sigmoidal, the apices acute, hyaline, not constricted at the single ± median septum, smooth, without a gelatinous sheath or appendages.