Karstenia idaei  

Thallus absent. Apothecia immersed, 0.3–0.5 mm diam., raising the substratum into small pustules and then splitting it irregularly, the exciple forming several teeth which are reflexed when the apothecium is rehydrated, colourless, ca 60 µm thick, composed of vertically-oriented, short-celled hyphae 2.5–3 (–4) µm diam., lined with a fringe of cells ca 10 × 2.5 µm in size. Paraphyses numerous, filiform, I–, ca 1 µm diam., not apically enlarged or branched. Asci short-stalked, uniformly thin-walled, lacking a defined apical apparatus, I–, 80–100 × 10–14 µm, 8-spored. Ascospores 40–60 × 3–4 µm, cylindrical, barely tapered basally, transversely multiseptate, the cells 4–5 µm in length.

The status of K. idaei as a British species needs confirmation. The description has been adapted from Sherwood (1977).