hymenophore

The hymenophore is the spore-bearing surface of a fungal fruiting body. It is the tissue on which the hymenium resides and, in basidiomycete fungi, the principal area where basidia produce basidiospores. The hymenophore forms the interface between the fungus and its environment, exposing the spores to air for dispersal.

It can take several distinct architectures. Lamellate or gilled hymenophores have blade-like plates (gills) under the cap; this form is common in many mushrooms. Poroid hymenophores have a network of pores, as seen in boletes and many polypores. Hydnoid or dentate hymenophores bear tooth-like projections, as in Hericium or some Hydnellum species. Some fungi exhibit crust-like or resupinate forms, where the spore-bearing surface lies flat on or directly against the substrate rather than forming a cap underside.

The structure and arrangement of the hymenophore are important in identification and taxonomy, reflecting evolutionary relationships among fungi. As the fruiting body matures, the hymenophore develops its characteristic form, which can affect spore release by wind, moisture, or contact with air. Microscopically, the hymenophore hosts the hymenium, the fertile tissue containing basidia and spores in basidiomycetes (or asci and ascospores in some ascomycetes).

Etymology and scope: the term derives from Greek hymen, membrane, and phore, bearing. The concept encompasses the diverse, spore-producing surfaces across fungal forms, from gilled mushrooms to pore-bearing polypores and toothed fungi.