"The hymenium is the layer of cells containing the spore-bearing cells (usually basidia or asci) of the fungus. The hymenophore is a collective term for the fleshy structures that bear the hymenium. Thus, in a gilled mushroom, all the gills constitute the hymenophore, and the hymenium is the layer of cells on the surface of those gills. Although the hymenophore may be convoluted and enclosed within the fruiting body, the hymenium still has to be, in some sense, on the 'outside' of the hymenophore in order for either of these structure to qualify for their names. Otherwise, you have a gleba, inside a peridium." Hymenium.