Introduction to fungi and cultivated mushrooms

Fungi

Fungi form one of the major kingdoms of living organisms. Currently, British, Australian and Latin American textbooks may describe five kingdoms (Animalia, Plantae, Fungi, Protista, and Prokaryota or Monera) while textbooks in the US most often use a system of six kingdoms (Animalia, Plantae, Fungi, Protista, Archaea and Bacteria).

Fungi are not to be confused with plants as they lack chlorophyll and therefore cannot photosynthesise their food from carbon dioxide and water. Instead, they absorb their food through thin filaments, which are called hyphae, made up of many cells arranged end to end. A fungal mycelium consists of these colourless threads of hyphae which grow through the substrate and then, if conditions are right, produce a fruiting body. This is what we recognise as the mushroom or toadstool. This structure produces and distributes the spores made after meiosis and therefore reproduces the species.

Electronmicrograph of hyphae
(of the mushroom Pleurotus)

Image provided by Dra Carmen Sánchez, Laboratory of Biotechnology, Research Centre for Biological Sciences, Universidad
Autónoma de Tlaxcala, México.

The mushrooms are the fruiting bodies, on the underside of which the sexual spores are formed. The fruiting bodies are different for each species, and there are many diverse and colourful examples, some very different from the the white button mushrooms seen in supermarkets.

Lentinula (Shiang-gu or Shiitake)
© Prof. S. W. Chiu.

The biological definition of fungi is that they:

are eukaryotic (organisms that have DNA contained in a nucleus);grow as hyphae;have rigid cell walls containing chitin (a strong material made of nitrogenous polysaccharides);obtain nutrients by secreting enzymes and absorbing digestion products from the substrate;
produce spores for reproduction and dispersal.

Cultivated Mushrooms

Mushrooms are cultivated around the world, global annual production being in the region of 12 million metric tonnes. They are an ideal source of food as they contain high levels of protein, containing all the essential amino acids and have virtually no cholesterol (see section 4.12 by Stephanie Ingram). Agaricus bisporus or the common white cultivated mushroom is the most extensively cultivated mushroom in the world accounting for about 46% of the total world crop of cultivated mushrooms. A. bisporus is also commonly known as the button mushroom, and in the market place it is sold under a variety of what are effectivly 'brand names', such as portabello/portabellas (which are large open-capped mature mushrooms) criminis (immature mushrooms), or the products of different strains like whites or chestnuts.

It is grown on composted straw and animal manure indoors where the temperature, humidity and carbon dioxide levels are tightly controlled. It is mainly grown in Europe, America, China and Australasia. There has been a big increase in the interest in more 'exotic' mushrooms in the last twenty-five years, and now species such as Lentinula and Pleurotus can be found alongside Agaricus in most supermarkets.

Agaricus bisporus
© David Moore

Lentinula edodes
© Prof. S. W. Chiu.

Lentinula edodes, or the Shiang-gu (the Chinese name, or Shiitake (the Japanese name), is traditionally grown on logs outdoors in forests. Environmental manipulation of the crop is achieved by heavy watering, shading or positioning the logs in areas of different microclimate. The cropping period is 3 to 7 years. A more intensive cultivation technique is growing in popularity involving growth on synthetic logs made mainly from sawdust, wood chippings and other agricultural wastes compressed into plastic bags. Lentinula global production in 2002 was about 1.8 million tonnes compared with about 6 million tonnes of Agaricus. 80% of production occurs in China, though it is also a major farming industry in Japan and South Korea is also cultivated commercially increasingly in Europe and North America.

Pleurotus species or oyster mushroom. This can be grown on a wide range of plant wastes compressed in plastic bags. Oyster mushroom production is light dependent. Some growers operate a 12 hour light cycle using fluorescent lamps. Pleurotus is the second most important mushrooms in terms of production, representing about 26% of the world market share today. Production of these mushrooms has increased by over 60% in the last 25 years. China is the major producer, though they are grown worldwide.

Pleurotus
©Prof. S. W. Chiu.

Other Cultivated Fungi

Here are some other fungi which are cultivated

Ganoderma © Prof. S. W. Chiu

Ganoderma
Some species of fungi are cultivated for medicinal properties instead of as food. Ganoderma is cultivated mainly in China where it is called lingzhi. It has been described as being able to prevent a wide range of clinical conditions including chronic bronchitis, coronary heart disease and cancer.

Volvariella volvacea or Paddy Straw mushroom.
This is another fungus cultivated for food. It made up around 6% of total world production of cultivated mushrooms in 2002. As its name suggests it is grown mainly on rice straw, though other wastes do make suitable substrates. Unlike other exotic mushrooms it is sold at an immature stage. A low yield and poor storage qualities have restricted the production of this crop.

Volvariella volvacea
© Prof. S. W. Chiu.

Wild Fungi

Here is a gallery of 100 our own digital photographs of fungi. Click on any of the low resolution gallery images to download high resolution JPG graphic files suitable for your own image manipulation or poster-making projects. As with other items on this website, there are no copyright issues for educational users, but all rights are reserved for any commercial use. If you wish to use any of this material commercially, contact the webmaster. Even more images of this sort can be found on websites hyperlinked on the General Information page.

Agaricus macrosporus

Agaricus sylvaticus Blushing Wood Mushroom

Aleuria aurantia Orange Peel Fungus

Amanita muscaria Fly Agaric

Sam finds a troop of Fly Agarics Children are safe with mushrooms in the wild, providing they don't try to eat them!

Photo: Becky Moore

Sam's troop of Fly Agarics

Photo: Becky Moore

Armillaria mellea Honey Fungus (note the rhizomorphs on the left)

Auricularia auricula-judea Jelly Ear

Bjerkandera adusta Smoky Bracket

Boletus parasiticus (parasitising a puffball)

Calocera cornea Small Stagshorn

Colocera viscosa Yellow Stagshorn

Claviceps purpurea Ergot

Clavulinopsis corniculata Meadow Coral

Clavulinopsis fusiformis Golden Spindles

Clitocybe nebularis Clouded Agaric

Coprinus comatus Shaggy Inkcap or Lawyer's Wig

Coprinellus micaceus Glistening Inkcap

Cordyceps militaris Scarlet Caterpillar club (parasitic on insect pupa)

Craterellus cornucopioides Horn of Plenty

Crepidotus variabilis Variable Oysterling

Crucibulum laeve Common Bird's Nest

Cultivated mushrooms: Agaricus bisporus, three species of Pleurotus, and Leninula edodes

Cyathus striatus Fluted Bird's Nest

Daldinia concentrica King Alfred's Cakes or Cramp Balls

Exidia thuretiana White Brain Fungus

A Fairy Ring (of Hebeloma crustuliniforme around the remains of its original host tree)

Fistulina hepatica Beefsteak Fungus

Ganoderma applanatum Artist's Bracket (growing from a fallen log)

Ganoderma (luccidum?) as Lingzhi - sold as a medicine

Geastrum fornicatum Arched Earthstar

Geastrum triplex Collared Earthstar

Guignardia phylloprena on holly

Gymnopilus penetrans Common Rustgill

Hygrocybe chlorophana Golden Waxcap

Hypholoma fasciculare Sulphur Tuft

Laccaria amethystina Amethyst Deceiver

Lactarius deterrimus False Saffron Milkcap

Lepista flaccida Tawny Funnel Cap

Lepista nuda Wood Blewit

Lycoperdon echinatum Spiny Puffball

Lycoperdon perlatum Common Puffball

Macrolepiota rhacodes Shaggy Parasol (a very large mushroom, but look at the coin)

Marasmius setosus (a very tiny mushroom, on a penny to compare with the Shaggy Parasol)

Marasmius setosus (on beech litter)

Mycena metata

Nectria cinnabarina Coral Spot

Neobulgaria pura Beech Jellydisk

Otidea onotica Hare's Ear

Oudemansiella mucida Porcelain Mushroom

Photo: Ted Pitman

Peziza badia Bay Cup

Phallus impudicus Stinkhorn

Photo: Paul Dyer

Phallus impudicus Stinkhorn (a young 'egg' sliced to show the unexpanded 'mushroom' inside)

Phellinus ferruginosus Rusty Porecrust

Pleurotus cornucopiae Branching Oyster Mushroom

Pleurotus ostreatus Oyster Mushroom (cultivated)

Psathyrella multipedata Clustered Brittlestem

Pseudohydnum gelatinosum (a fungus that has teeth rather than gills or pores)

Puccinia buxi Box Rust

Ramaria fumosa

Ramaria stricta Upright Coral

Rhytisma acerinum Sycamore Tarspot

Rotting fruit and vegetables

Russula chloroides Blue Band Brittlegill

Russula mairei

Russula ochroleuca Ochre Brittlegill

Scleroderma citrinum Common Earthball

Scleroderma citrinum Common Earthball (sliced open to show the spore mass inside)

Sheltering insects under the cap of of Hebeloma crustuliniforme

Taphrina Witch's Broom

Trametes versicolor Turkey Tail

Trametes versicolor Turkey Tail (in winter)

Tremella mesenterica Yellow Brain

Tricholomopsis rutilans Plums and Custard

Xylaria hypoxylon Candle Snuff Fungus

Xylaria polymorpha Dead Man's Fingers

Return to Mostly Mushroom Farming home page

Return to David Moore's World of Fungi contents page