See What Happens When You Eat Mushrooms

Mushrooms, the typical umbrella-shaped fruiting body (sporophore) of some fungi, usually Agaricales in Phallium bacidiomota but also of some other groups. Popularly, the term is used to identify edible sporophores; The term toadstool is often reserved for inedible or poisonous sporophores. However, there is no scientific distinction between the two names, and either can be applied properly with any fleshy fungal structure. In a very limited sense, mushrooms indicate common edible fungi (Agicicus campestris) of fields and plains. A very closely related species, A. Bisporus is a mushroom grown commercially and seen in markets.

Umbrella-shaped sporophores are mainly found in the Agaric family (Agaricaceae), whose members bear thin, bradylic gills on the underscores of the cap from which the spores are shed. Agric's sporophore includes a cap (pileus) and a stalk (stipe). The sporophore originates from an extensive underground network of threadlide strands (mycelium). An example of agaric is the honey mushroom (Armillaria melia). Depending on the supply of food available, mushroom mycelia can live for hundreds of years or die in a few months. As long as nutrition is available and temperature and humidity are appropriate, a mycelium will produce a new crop of sporophore every year in its fruiting season.

The fruiting bodies of some mushrooms are in arcs or rings called fairy rings.  The mycelium begins with a spore that falls at a favorable location and forms strands (hyphae) that develop in all directions, eventually forming a circular mat of underground hypal threads.  Frying bodies built on the side of this pot can widen the ring for hundreds of years.

A few mushrooms belong to the order boletals, which carry pores in an easily removable layer at the bottom of the shell.  The agarics and boletes contain most of the forms known as mushrooms.  However, other groups of fungi are considered mushrooms, at least by laymen.  These include the hidnums or hedgehog mushrooms that have teeth, spines or warts on the underside of the shell (eg Dentinum repandum, Hydnum imbricatum) or at the tips of branches (eg H. coralloides, Hericium caput-ursi).  The polypores, duty fungi or hook fungi (order Polyporales) have tubes under the shell 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 their growth every year and thus produce annual growth strokes with which their age can be estimated.  Examples are the seed of the dryad (Polyporus squamosus), the steak fungus (Fistulina hepatica), the sulfur fungus (P. sulphureus), the artist fungus (Ganoderma applanatum, or Fomes applanatus), and species of the genus Trametes.  The clavarias, or club fungi (eg Clavaria, Ramaria), are a shrub, bluefish or coral in the growth habit.  One club fungus, the cauliflower fungus (Sparassis crispa), has flattened branches that lie close together, giving the vegetable cauliflower its appearance.  The cantharelloid fungi (Cantharellus and its relatives) are club-, cone-, or trumpet-shaped mushroom-shaped forms with an elongated upper that bears coarsely folded edges along the underside and descends along the stem.  Examples are the highly prized edible chanterelle (C. cibarius) and the mushroom of the abundant horn (Craterellus cornucopioides).  Emerging ball (family Lycoperdaceae), stinking horns, earth stars (a kind of puffball) and fungus of bird nests are usually treated with the mushrooms.  The moral (Morchella, Verpa) and false moral or lorchels (Gyromitra, Helvella) of the phylum Ascomycota are commonly included in the real mushrooms because of their shape and fleshy structure;  they look like a deep folded or chopped spongy top above a hollow trunk.  Some are from the valued edible fungi (e.g. Morchella esculenta).  Another group of ascomycetes includes the cup fungi, with a blue-headed or dish-like fruit structure, sometimes strongly colored.