A mushroom is the visible, umbrella-shaped reproductive structure (sporophore) of certain fungi . While the term mushroom is commonly used to describe edible sporophores, toadstool often refers to inedible or poisonous ones; however, there is no scientific distinction between the two. Fungi, including mushrooms, reproduce by forming and releasing spores, either through asexual or sexual methods. Sexual reproduction involves the fusion of nuclei from two sex cells, while asexual reproduction creates a genetic duplicate of the parent. Some mushrooms, such as fly agaric, reproduce sexually with basidiospores, which are externally produced on basidia cells. Animals that eat mushrooms can also aid in reproduction by relocating basidia via fecal matter. Many other groups of fungi are considered mushrooms by laymen, such as hydnums or hedgehog mushrooms, polypores , shelf fungi, or bracket fungi.

How are mushrooms related to fungi?

Mushrooms are fungi; the Latin word for mushroom, fungus (plural fungi ), has come to represent the whole group. Mushrooms are the most easily recognized fungi, though not the most numerous or economically significant. The study of fungi is known as mycology, derived from the Greek word for mushroom, mykēs . The mycelium, a network of branched, tubular filaments called hyphae, forms the thallus, or undifferentiated body, of a typical fungus. The underground hyphae of a mushroom obtain food from organic matter and grow outward. The hyphal branches at the edge of the mycelium can organize into tissues that develop aboveground into mushrooms.

Where do mushrooms usually grow?

Mushrooms thrive in various environments, depending on the species. Many mushrooms are saprotrophic saprotrophs , meaning they get their nutrition from dead organic material. These can be widely distributed if their habitats have sufficient organic content. For example, you can find some fungi, like Marasmius , on the forest floor, decomposing leaves and twigs. Other species of fungi, such as Pilobolus , feed primarily on the dung of herbivores. Some mushrooms have specific requirements. Tricholoma matsutake , or matsutake mushrooms, grow in dense pine forests and have a symbiotic relationship with pine and beech trees. Fly agaric mushrooms grow in forests, pastures, and fields throughout temperate and boreal regions of the Northern Hemisphere. Many fungi are mesophilic, with optimum growth between 68–86 °F (20–30 °C). Humidity is also important for the development of many fungal diseases in plants, with spore germination occurring best at 90 to 95 percent relative humidity.

What do mushrooms eat or need to live?

Mushrooms, as fungi, obtain carbon and energy by absorbing organic matter, with carbohydrates being their preferred carbon source. They can metabolize soluble carbohydrates like glucose, xylose, sucrose, and fructose, as well as insoluble ones like starches and cellulose. Saprotrophic fungi get their nutrients from dead organic material. They secrete enzymes onto the surface they're on to digest food, then directly absorb it through their hyphal walls. They also need elements like phosphorus, sulfur, potassium, magnesium, iron, zinc, manganese, copper, oxygen, and hydrogen. Some require vitamins like thiamine and biotin from their environment. Some fungi have developed mechanisms for trapping microorganisms such as amoebas, roundworms (nematodes), and rotifers.

What are the main parts of a mushroom?

The main parts of a mushroom include the mycelium , stipe , and mushroom cap . The mycelium consists of branched, tubular filaments that form the fungus's body. The stipe is the stalk that supports the cap. The mushroom cap is the top part of the mushroom. Some mushrooms also have structures like pores, gills, or teeth on the underside of the cap, which aid in spore dispersal.

How can you tell if a wild mushroom is safe or poisonous?

There are no simple rules for determining if a wild mushroom is safe to eat. It is essential to have every mushroom identified accurately by an expert before consumption. Many poisonous mushrooms closely resemble edible species, and toxicity can vary based on ecological conditions and geographic location. Some mushrooms are poisonous when fresh but edible after cooking or preservation, while others remain toxic despite preparation. Furthermore, some individuals may be poisoned by mushrooms that do not affect others. To avoid mushroom poisoning , only consume wild mushrooms positively identified as edible by a competent authority. The safest approach is to eat only cultivated species.

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Images, Videos & Interactives

A young adult wearing overalls and a baseball hat in nature. A paper cutout with images of berries, nuts, and

Two Amanita pantherina mushrooms with brown caps covered in white spots grow among moss and fallen leaves.

A ring of white mushrooms grows in a circle on the forest floor among grass and leaf litter, with trees and shrubs surrounding the area.

Several Ganoderma applanatum, or artist's bracket fungi, grow in horizontal shelves with brown tops and white edges on the trunk of a mossy tree.

Illustration of a red-capped mushroom wearing a red cape next to bold text reading 'Can fungi save the world?' with a smokestack in the background.

Small brown mushrooms growing at the base of a tree.

A single death cap mushroom, Amanita phalloides, with a pale greenish cap and white gills, grows from the forest floor among fallen leaves and branches.

At a Glance

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Related Topics:: death cap; portobello mushroom; snow mushroom; sulfur mushroom; panther cap

On the Web:: National Center for Biotechnology Information - Mushroom Toxicity (Oct. 17, 2026)

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Edible mushrooms

Commercially important, edible mushrooms include portobellos (Agaricus bisporus), whose forms include button mushrooms, cremini, and baby bellas, and shiitake (Lentinula edodes). The morels (Morchella, Verpa) and false morels or lorchels (Gyromitra, Helvella) are popularly included with the true mushrooms because of their shape and fleshy structure; they resemble a deeply folded or pitted conelike sponge at the top of a hollow stem. Some are among the most highly prized edible fungi (e.g., Morchella esculenta). Edible truffles (various Tuber species), which hardly resemble mushrooms, are also popularly labeled as such. These and other edible mushrooms and fungi are free of cholesterol and contain small amounts of essential amino acids and B vitamins. However, their chief worth is as a specialty food of delicate, subtle flavour and agreeable texture. By fresh weight, the common commercially grown mushroom is more than 90 percent water, less than 3 percent protein, less than 5 percent carbohydrate, less than 1 percent fat, and about 1 percent mineral salts and vitamins.

Poisoning by wild mushrooms is common and may be fatal or produce merely mild gastrointestinal disturbance or slight allergic reaction. It is important that every mushroom intended for eating be accurately identified (see also mushroom poisoning and death cap mushroom).

Chef tossing vegetables in a frying pan over a burner (skillet, food).

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Form and major groups

Umbrella-shaped sporophores are found chiefly in the agaric family (Agaricaceae), members of which bear thin, bladelike gills on the undersurface of the cap from which the spores are shed. A few mushrooms belong to the order Boletales, which bear pores in an easily detachable layer on the underside of the cap. The sporophore of an agaric consists of a cap (pileus) and a stalk (stipe). The sporophore emerges from an extensive underground network of threadlike strands (mycelium). An example of an agaric is the honey mushroom (Armillaria mellea). Mushroom mycelia may live hundreds of years or die in a few months, depending on the available food supply. As long as nourishment is available and temperature and moisture are suitable, a mycelium will produce a new crop of sporophores each year during its fruiting season.

Fruiting bodies of some mushrooms occur in arcs or rings called fairy rings. The mycelium starts from a spore falling in a favourable spot and producing strands (hyphae) that grow out in all directions, eventually forming a circular mat of underground hyphal threads. Fruiting bodies, produced near the edge of this mat, may widen the ring for hundreds of years.

Other “mushrooms”

While the agarics and boletes include most of the forms known as mushrooms, other groups of fungi, however, are considered to be mushrooms, at least by laymen. Among these are the hydnums or hedgehog mushrooms, which have teeth, spines, or warts on the undersurface of the cap (e.g., Dentinum repandum, Hydnum imbricatum) or at the ends of branches (e.g., H. coralloides, Hericium caput-ursi). The polypores, shelf fungi, or bracket fungi (order Polyporales) have tubes under the cap as in the boletes, but they are not in an easily separable layer. Polypores usually grow on living or dead trees, sometimes as destructive pests. Many of them renew growth each year and thus produce annual growth layers by which their age can be estimated. Examples include the dryad’s saddle (Polyporus squamosus), the beefsteak fungus (Fistulina hepatica), the sulfur fungus (P. sulphureus), the artist’s fungus (Ganoderma applanatum, or Fomes applanatus), and species of the genus Trametes. The clavarias, or club fungi (e.g., Clavaria, Ramaria), are shrublike, clublike, or coral-like in growth habit. One club fungus, the cauliflower fungus (Sparassis crispa), has flattened clustered branches that lie close together, giving the appearance of the vegetable cauliflower.

The cantharelloid fungi (Cantharellus and its relatives) are club-, cone-, or trumpet-shaped mushroomlike forms with an expanded top bearing coarsely folded ridges along the underside and descending along the stalk. Examples include the highly prized edible chanterelle (C. cibarius) and the horn-of-plenty mushroom (Craterellus cornucopioides). Puffballs (family Lycoperdaceae), stinkhorns, earthstars (a kind of puffball), and bird’s nest fungi are usually treated with the mushrooms. Another group of ascomycetes includes the cup fungi, with a cuplike or dishlike fruiting structure, sometimes highly coloured.

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Other unusual forms, not closely related to the true mushrooms but often included with them, are the jelly fungi (Tremella species) and the ear fungus (Auricularia auriculara-judae).

The Editors of Encyclopaedia BritannicaThis article was most recently revised and updated by Meg Matthias.

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Edible mushrooms

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Form and major groups

Other “mushrooms”