Microscopic features

Ahymeniumis a layer of microscopic sporebearing cells that covers the surface of gills. In the nongilled mushrooms, the hymenium lines the inner surfaces of the tubes ofboletesand polypores, or covers the teeth of spine fungi and the branches of corals. In the Ascomycota, spores develop within microscopic elongated, saclike cells calledasci, which typically contain eight spores in each ascus. TheDiscomycetes, which contain the cup, sponge, brain, and some clublike fungi, develop an exposed layer of asci, as on the inner surfaces ofcup fungior within the pits ofmorels. ThePyrenomycetes, tiny darkcolored fungi that live on a wide range of substrates including soil, dung, leaf litter, and decaying wood, as well as other fungi, produce minute, flaskshaped structures calledperithecia, within which the asci develop.