子实层（英语：hymenium），是真菌子实体组织，其细胞生长为担子或子囊、形成孢子。一些物种的子实层产生担子或子囊，而其他细胞则发展成为囊状体（担子菌纲）或侧丝（子囊菌纲）。囊状体在生物识别上有重要意义，是菌类特征及分类的首要特征。以下是一些例子用于分别担子菌门和子囊菌门。

The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some cells develop into sterile cells called cystidia (basidiomycetes) or paraphyses (ascomycetes). Cystidia are often important for microscopic identification. The subhymenium consists of the supportive hyphae from which the cells of the hymenium grow, beneath which is the hymenophoral trama, the hyphae that make up the mass of the hymenophore.