Of the bewildering variety of organisms that live on the planet Earth—and perhaps the most unusual and peculiarly different from human beings—are fungi. Members of the kingdom Fungi range from single-celled yeasts to Armillaria ostoyea, a species that covers 2,200 acres (890 hectares)! Also included are mushrooms that are commonly consumed, the black mold that forms on stale bread, the mildew that grows on damp shower curtains, rusts, smuts, puffballs, toadstools, shelf fungi, and the death cap mushroom, Amanita phalloides. Fungi are able to rot timber, attack living plants, spoil food, and afflict humans with athlete’s foot or even worse maladies. Fungi also decompose dead organisms, fallen leaves, and other organic materials. In addition—and on the bright side—fungi produce antibiotics and other drugs, make bread rise, and ferment beer and wine. (For more about fungi, see the chapter “Fungi.”)