Mushrooms

In the Basidiomycetes, usually four spores develop on the tips of thin projections called sterigmata, which extend from a club-shaped cell called a basidium. The fertile portion of the Gasteromycetes, called a gleba, may become powdery as in the puffballs or slimy as in the stinkhorns. 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.
The most important microscopic feature for identification of mushrooms is the spores themselves. Their color, shape, size, attachment, ornamentation, and reaction to chemical tests often can be the crux of an identification. Spores often have 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.