Agaricales

Agaricales
Agaricus campestris (Agaricaceae)
Scientific classification
Kingdom: Fungi
Subkingdom: Dikarya
Phylum: Basidiomycota
Subphylum: Agaricomycotina
Class: Agaricomycetes
Subclass: Agaricomycetidae
Order: Agaricales
Underw., 1899[1]
Families
33 families

Genera Incertae sedis

  • Amogaster
  • Brunneocorticium
  • Cheilophlebium
  • Cleistocybe
  • Cribrospora
  • Disporotrichum
  • Mesophelliopsis
  • Panaeolina
  • Panaeolus
  • Phlebophyllum
  • Plicatura
  • Plicaturopsis
  • Sedecula
  • Setchelliogaster
  • Trichocybe

The fungal order Agaricales, also known as gilled mushrooms (for their distinctive gills), or euagarics, contains some of the most familiar types of mushrooms. The order has 33 families, 413 genera, and over 13000 described species.[2] They range from the ubiquitous common mushroom to the deadly destroying angel and the hallucinogenic fly agaric to the bioluminescent jack-o-lantern mushroom.

Contents

Classification

Macrolepiota procera (Parasol mushroom)

Some notable fungi with gill-like structures, such as chanterelles, have long been recognized as being substantially different from usual Agaricales. Interestingly, molecular studies are showing more groups of agarics as being more divergent than previously thought, such as the genera Russula and Lactarius belonging to a separate order Russulales, and other gilled fungi, including such species as Paxillus involutus and Hygrophoropsis aurantiaca showing a closer affinity with Boletes in the order Boletales.

Also, some other quite distinctive fungi, the puffballs, and some clavaroid fungi, e.g. Typhula, and the Beefsteak fungus have been recently been shown to lie within the Agaricales.

The term agaric had traditionally referred to Agaricales, which were defined as exactly those fungi with gills. Given the discoveries described above, those two categories are not synonymous (although there is a very large overlap between the two groups).

Distribution and habitat

Agarics are ubiquitous, being found across all continents. Most are terrestrial, their habitats including all types of woodland and grassland, varying largely from one genus to another. Agarics were long thought to be solely terrestrial, until the 2005 discovery of Psathyrella aquatica, the only gilled mushroom known to fruit underwater.[3]

Cortinarius archeri

Characteristics

Basidiocarps of the agarics are typically fleshy, with a stipe, often called a stem or stalk, a pileus (or cap) and lamellae (or gills), where basidiospores are produced. This is indeed the stereotyped structure of what we would call a mushroom.

Life cycle

The fungus fruit body is the spore-producing stage of the life cycle. Most fungi reproduce by spores and the fruit bodies are developed specifically for the production and dispersal of spores. The spores produced by fruit bodies are usually the result of sexual reproduction.[4]

The fruit body is the visible part of the growing fungus. It is supported by and develops from an extensive network of thread-like filaments called hyphae. Hyphae are often collectively termed the mycelium; the food-absorbing part of the fungus—as opposed to the spore-producing fruit body of the fungus—is called the vegetative mycelium. The individual hyphae that compose the mycelium absorb nutrients and water from the substratum in which they are growing. When the nutrient supply is adequte and envirnmental conditions are favorable, some fungi may grow in the same location for several years. Fungi cannot make their own food, namely carbohydrates, as can green plants. Some species are saprobic, obtaining nutrients from dead organic material, whereas others are parasitic on living plants or animals or even on other fungi. Many fungi, especially gilled mushroomes and boletes, have an extensive mycelium that lives in association with the roots of woody plants. This association, which is beneficial to both the fungus and host plant, is termed a mycorrhiza.[4]

When the environmental conditions are favorable and the mycelium is at the proper stage of development, one or more fruit bodies are produced by the fungus. The actual conditions necessary for fruit body formation and spore production are not clearly understood. Humidity, light, temperature, aeration, and nutrition are all factors thought to be important in fruit body formation. The genetic makeup and the general physiology of the fungus hyphae are also important in the initiation and formation of young fruit bodies and their development to a mature stage. The spores produced by a fruit body are released when it is mature. When they land in a suitable environment, the spores germinate and the hyphae grow to initiate the life cycle anew.[4]

See also

References

  1. ↑ Underwood, L.M. (1899). Moulds, mildews and mushrooms: a guide to the systematic study of the Fungi and Mycetozoa and their literature. New York: Henry Holt. pp. 97. 
  2. ↑ Kirk PM, Cannon PF, Minter DW, Stalpers JA. (2008). Dictionary of the Fungi. 10th ed. Wallingford: CABI. p. 12. ISBN 0-85199-826-7. 
  3. ↑ Frank JL, Coffan RA, Southworth D. (2010). "Aquatic gilled mushrooms: Psathyrella fruiting in the Rogue River in southern Oregon". Mycologia 102 (1): 93–107. doi:10.3852/07-190. 
  4. ↑ 4.0 4.1 4.2 Alexopolous et al., pp. 508–43.

Cited texts

External links