Editing Mushroom (section)

===Microscopic features===
A [[hymenium]] is a layer of microscopic spore-bearing cells that covers the surface of gills. In the nongilled mushrooms, the hymenium lines the inner surfaces of the tubes of [[bolete]]s and polypores, or covers the teeth of spine fungi and the branches of corals. In the Ascomycota, spores develop within microscopic elongated, sac-like cells called [[Ascus|asci]], which typically contain eight spores in each ascus. The [[Discomycetes]], which contain the cup, sponge, brain, and some club-like fungi, develop an exposed layer of asci, as on the inner surfaces of [[cup fungi]] or within the pits of [[morel]]s. The [[Pyrenomycetes]], tiny dark-colored fungi that live on a wide range of substrates including soil, dung, [[leaf litter]], and decaying wood, as well as other fungi, produce minute, flask-shaped structures called [[perithecia]], within which the asci develop.<ref name="Ammirati1985pp25-34">[[#Ammirati|Ammirati]] ''et al''., pp. 25–34.</ref>

In the basidiomycetes, usually four spores develop on the tips of thin projections called [[sterigmata]], which extend from club-shaped cells called a [[basidia]]. The fertile portion of the [[Gasteromycetes]], called a [[gleba]], may become powdery as in the puffballs or slimy as in the [[stinkhorn]]s. Interspersed among the asci are threadlike sterile cells called [[paraphyses]]. Similar structures called [[cystidia]] often occur within the hymenium of the Basidiomycota. Many types of cystidia exist, and assessing their presence, shape, and size is often used to verify the identification of a mushroom.<ref name="Ammirati1985pp25-34" />

The most important microscopic feature for identification of mushrooms is the spores. Their color, shape, size, attachment, ornamentation, and reaction to [[Chemical tests in mushroom identification|chemical tests]] often can be the crux of an identification. A spore often has a protrusion at one end, called an apiculus, which is the point of attachment to the basidium, termed the apical [[germ pore]], from which the hypha emerges when the spore germinates.<ref name="Ammirati1985pp25-34" />