What are mushrooms & toadstools/fungi?


Mushroom & toadstool/fungi terminology

Shaggy inkcap Coprinus comatus © Ita McCobb

The all-encompassing name for mushrooms and toadstools is "fungi". Fungi usually grow from minute spores produced by the parent mushroom or toadstool. These spores are then forced out of the mushroom or toadstool and float in the air until they settle on suitably humid areas of ground, decaying trees or even food – humid conditions being their preferred environment.

The world of mushrooms and toadstools is littered with special terms. The generic term for mushrooms and toadstools being”fungi”, which is the plural form of “fungus” – meaning any of a large group of spore-producing organisms that feed on organic matter. Fungi include mould, yeast, mushrooms and toadstools.

The scientific study of fungi is called “mycology”, which is why people and animals that eat mushrooms are known as “mycophagists”. In fact, you’ll find that most technical terms that relate to mushrooms and toadstools begin with “myco”, which comes from the Greek “mukes” to mean “relating to fungi”.

Two words you may also frequently come across are: 
Agaric – often used to describe any fungus with an umbrella-like cap with gills beneath. Bolete – often used generally to describe any toadstool with pores (not gills) beneath.

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Mushroom & toadstool/fungi structure

Most mushrooms and toadstools are normally composed of three main elements: a stalk (sometimes called the stem or stipe), a cap and spore-bearing surfaces – normally on the underside of its cap.

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Mushroom & toadstool/fungi stalks

Tinder bracket Fomes fomentarius © Ita McCobb

There are six main stalk-related forms:

Complete lack of stalk – e.g. Tinder fungus Fomes fomentarius and Truffles Tuber aestivum and occasionally Puffballs Lycoperdon perlatum.

Squat stalk – e.g. White button mushrooms Agaricus bisporus, Parasol mushrooms Macrolepiota procera and Shaggy parasol Macrolepiota rhacodes.

Regular/slim stalk – e.g. the Porcelain fungus Oudermansiella mucida, Red staining/Deadly fibrecap Inocybe patouillardii and Red-cracked boletus Boletus chrysentero.

Growth at the base – e.g. the Fly agaric Amanita muscaria, Destroying angel Amanita virosa and the Tawny grisette Amanita fulva.

Bulbous base – e.g. the Common puffball Lycoperdon perlatum, Chanterelle Cantharellus cibarius and Meadow waxcap Hygrocybe pratensis.

Club base – e.g. the Bay boletus Boletus badius, the Blushing-wood mushroom Agaricus silvaticus and the Cep (Porcini, King Bolete) Boletus edulus.

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Mushroom & toadstool/fungi caps

Fly algaric Amanita muscaria © Jennifer Hope-Morley

Nine main forms of cap exist:

Campanulate (bell-shaped)

Conical (triangular)

Convex (domed)

Concave/depressed (dipping in the centre)

Flat (level top)

Infundibulum (funnel-shaped cavity)

Ovate (shape of half an oval)

Umbilicate (small central dip)

Umbonate (with a swelling or protuberance in the centre).

Take care when identifying toadstools and mushrooms as their caps often change shape as they mature – so what started out as ovate can become flat or even infundibulum (what a fabulous word!) as it matures.

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Mushroom & toadstool/fungi spore-bearing surface

Bolete Boletus fragrans © Ita McCobb

There are four main types of spore-bearing surfaces under the cap:

Gills – feathery-like strips radiating out from the stalk – e.g. Field mushroom Agaricus campestris.

Pores – creating a sponge-like surface made up of tiny tubes running through the under cap structure, e.g. Red-cracked bolete Boletus chrysenteron, Beefsteak fungus Fistulina hepatica.

Ridges – coral-like, short raised veins running under the cap and into the stalk – e.g. the Horn of plenty Craterellus cornucopioide, Chanterelle Cantherellus cibarius.

Teeth – formed from thousands of tiny projections that create a surface similar to a rubber brush – e.g. the Hedgehog fungus Hydnum repandum.

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Mushroom & toadstool/fungi spore prints

When the mushroom and toadstool spores that are produced on spore-bearing surfaces under the cap are ready, they are dispersed by falling or floating away on the air. If you cut off a mushroom or toadstool cap and place it, underside-down, for several hours on a piece of paper it leaves a powdery impression, this is called a “spore print”, and is used by specialists to help classify and identify mushrooms. Spore print colours are generally white but can be brown, black, purple, pink, yellow or cream and occasionally blue, green or red.

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Mushroom & toadstool/fungi species confusion

Fly algaric Amanita muscaria  (young form) © Ita McCobb

It is important to remember that many mushrooms and toadstools are similar in shape, colour and form and so it is difficult to differentiate between them as they evolve and grow, particularly as to what you can and can't eat! They can look very different at different life stages.

For help identifying mushrooms see Edible mushrooms & Toxic mushrooms, or visit: nifg.org.uk. For general guidance read our Guide to picking & eating mushrooms.

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References: The British Mycological Society; Guides for the Amateur Mycologist – No.4, Guide for the Kitchen Collector:Preservation and Cooking of Fungi, Shelley Evans, BMS, 1994; Identifying Mushrooms, Peninsula Mycological Circle; How to tell if a mushroom is friend or foe, Jo Kessel, Daily Telegraph, 26 Oct 2010; Champignons vénéneux, E. Garnweidner, Mini guide Nanthan tout terrain 1991; Oxford English Dictionary, Oxford University Press; Champignons, toxiques & comestibles, Institut Klorane; Collins Fungi Guide, Stefan Buczacki, Collins; Mushrooms, Roger Phillips, MacMillan.