Ciboria coryli is a saprotrophic cup fungus in the family Sclerotiniaceae, found in temperate Europe. It typically fruits on the fallen catkins and nuts of hazel (Corylus avellana) in moist woodland, hedgerow, and scrub habitats, emerging from sclerotia within decaying plant material. The fruiting bodies are stalked discs, pale to medium brown, and rarely exceed one centimeter in diameter. Like other members of the genus, Ciboria coryli is a specialist on a particular plant substrate, in this case hazel reproductive material, which determines its seasonal and geographic distribution. It is classified as Least Concern, with populations stable in regions where hazel woodland persists. Hazel coppice and mixed deciduous woodland across central and western Europe provide suitable habitat. The species name coryli directly references its host plant genus. Identification from related species requires microscopic examination of spore size and shape, as well as the character of paraphyses and excipular cells. Ciboria coryli contributes to the decomposition of woodland leaf litter and the cycling of nutrients from fallen organic matter back into the soil. As with many small discomycetes, it is under-recorded relative to its actual abundance. Conservation of hazel-rich woodland habitats benefits this species alongside a wide range of other specialist fungi and invertebrates associated with hazel.