The term mushroom usually refers to the aboveground fruiting body (spore-producing structure) of fungi with a shaft and a cap, and in extension, referring to the entire fungi of such appearance, but is also used to refer to many visible fungi in general.
Mushrooms are used extensively in cooking many cuisines. However, many mushrooms are poisonous, often resembling edible varieties, and eating them can be fatal. Picking your own wild mushrooms is extremely risky - far riskier than gathering edible plants - and a practice not to be undertaken by amateurs. This is due to the fact that, while there are only about 400,000 species of plants worldwide, there are an estimated 1.5 million mushroom species. Further complicating this is the lower degree of variety in easily identifiable traits between mushroom species. Mushrooms and other fungi are studied by mycologists. People who collect mushrooms for consumption are known as mushroom hunters, and the act of collecting them as such is called mushroom hunting - an activity with potentially deadly outcome that one should be well prepared for before attempting.
The main types of mushrooms are agarics, boletes, chanterelles, tooth fungi, polypores, puffballs, jelly fungi, coral fungi, bracket fungi, stinkhorns, and cup fungi. "True mushrooms" are classified as Basidiomycota (also known as "club fungi").
One common method used to assist in identification of mushrooms is the spore print.
Currently, many species of mushrooms and fungi utilized as folk medicines for thousands of years are under intense study by ethnobotanists and medical researchers. Maitake, shiitake, and reishi varieties are prominent among those being researched for their anti-cancer, anti-viral, and/or immunity-enhancement properties.
Any large detonation of explosives, including that from a nuclear weapon, produces a mushroom cloud, so named because its shape resembles a mushroom.