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.