In fungi, a basidiocarp, basidiome or basidioma (plural: basidiomata), is the sporocarp

Sporocarp (fungi)

In fungi, the sporocarp is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne...

 of a basidiomycete, the multicellular

Multicellular organism

Multicellular organisms are organisms that consist of more than one cell, in contrast to single-celled organisms. Most life that can be seen with the the naked eye is multicellular, as are all animals and land plants.-Evolutionary history:Multicellularity has evolved independently dozens of times...

 structure on which the spore

Spore

In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...

-producing hymenium

Hymenium

The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some cells develop into sterile cells called cystidia or...

 is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts

Ustilaginomycetes

Ustilaginomycetes is the class of true smut fungi. They are plant parasites with about 1400 recognised species in 70 genera....

 do not produce such structures. As with other sporocarps, epigeous (above-ground) basidiocarps that are visible to the naked eye (especially those with a more or less agaricoid morphology) are commonly referred to as mushrooms, while hypogeous (underground) basidiocarps are usually called false truffles.

Structure

All basidiocarps serve as the structure on which the hymenium is produced. Basidia are found on the surface of the hymenium, and the basidia ultimately produce spores. In its simplest form, a basidiocarp consists of an undifferentiated fruiting structure with a hymenium on the surface; such a structure is characteristic of many simple jelly

Jelly fungi

The class Heterobasidiomycetes or jelly fungi is a paraphyletic group of several fungal orders: Tremellales, Auriculariales, Dacrymycetales. These fungi are so named because their foliose to irregularly branched fruiting body is, or appears to be, the consistency of jelly. Actually, many are...

 and club fungi. In more complex basidiocarps, there is differentiation into a stipe

Stipe (mycology)

thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...

, a pileus

Pileus (mycology)

The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...

, and/or various types of hymenophores.

Types

Basidiocarps are classified into various types of growth forms based on the degree of differentiation into a stipe, pileus, and hymenophore, as well as the type of hymenophore, if present.

Growth forms include:

• jelly fungus – fruiting body is an undifferentiated mass of jelly-like tissue.
• club fungus and coral fungus – erect fruiting body without a distinct stipe and pileus, either unbranched (club fungus) or profusely branched (coral fungus).
• polypore
  Polypore
  Polypores are a group of tough, leathery poroid mushrooms similar to boletes, but typically lacking a distinct stalk. The technical distinction between the two types of mushrooms is that polypores do not have the spore-bearing tissue continuous along the entire underside of the mushroom. Many...
  
   – fruiting body is hard, woody, and perennial, and often grows shelf-like on the side of a tree or log. Polypores have a pileus, and usually (but not always) tubes and no stipe.
• cantharelloid fungus – fruiting body with shallow fold-like lamellae running over most of the lower surface of the fruiting body and not much differentiation between the stipe and pileus.
• tooth fungus or "hydnoid fungus" – fruiting body with tooth-like hymenophores.
• gasteromycete or "gastroid fungus" – fruiting body has a ball-like shape and in which the hymenophore has become entirely enclosed on the inside of the fruiting body.
• false truffle
  False truffle
  A false truffle or a Hymenogastrale is any species of fungi that has truffle-resembling underground fruiting bodies that produce basidiocarps....
  
   – like a gasteromycete, however, but with a hypogeous (underground) fruiting body.
• secotioid fungus
  Secotioid
  Secotioid fungi are an intermediate growth form between mushroom-like hymenomycetes and closed bag-shaped gasteromycetes, where an evolutionary process of gasteromycetation has started but not run to completion...
  
   – like a gasteromycete, but with stipe. Though to be an evolutionarily intermediate stage between a gasteromycete and an agaric.
• agaric
  Agaric
  An agaric is a type of fungal fruiting body characterized by the presence of a pileus that is clearly differentiated from the stipe , with lamellae on the underside of the pileus. "Agaric" can also refer to a basidiomycete species characterized by an agaric-type fruiting body...
  
   or "agaricoid fungus" – fruiting body with a pileus, lamellae, and (usually) a stipe.
• bolete
  Bolete
  A bolete is a type of fungal fruiting body characterized by the presence of a pileus that is clearly differentiated from the stipe, with a spongy surface of pores on the underside of the pileus...
  
   – fruiting body with a pileus, a stipe, and tubes.

Basic divisions of Agaricomycotina

Agaricomycotina

The subphylum Agaricomycotina, also known as the hymenomycetes, is one of three taxa of the fungal division Basidiomycota . The Agaricomycotina contain some 20,000 species, and about 98% of these are in the class Agaricomycetes: most of the fungi known as mushrooms, including the bracket fungi and...

 were formerly based entirely upon the growth form of the mushroom. Molecular phylogenetic investigation (as well as supporting evidence from micromorphology and chemotaxonomy

Chemotaxonomy

Chemotaxonomy , also called chemosystematics, is the attempt to classify and identify organisms , according to demonstrable differences and similarities in their biochemical compositions. The compounds studied in most of the cases are mostly proteins, amino acids and peptides...

) has since demonstrated that similar types of basidiomycete growth form are often examples of convergent evolution

Convergent evolution

Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...

 and do not always reflect a close relationship between different groups of fungi. For example, agarics have arisen independently in the Agaricales

Agaricales

The fungal order Agaricales, also known as gilled mushrooms , or euagarics, contains some of the most familiar types of mushrooms. The order has 33 extant families, 413 genera, and over 13000 described species, along with five extinct genera known only from the fossil record...

, the Boletales

Boletales

The Boletales are an order of Agaricomycetes, containing over 1300 species with a diverse array of fruiting body types. The boletes are the best known members of this group, and until recently, the Boletales were thought to only contain boletes...

, the Russulales

Russulales

The Russulales are an order of the Agaricomycetes,...

, and other groups, while secotioid fungi and false truffles have arisen independently many times just within the Agaricales. http://www.mykoweb.com/articles/Homobasidiomycete_clades.html

External links

• Evolution & Morphology in the Homobasidiomycetes: The Clade/Morphology Chart by Gary Lincoff & Michael Wood, MykoWeb, November 27, 2005.
• "Mycomorphology Part 1: Why Do Mushrooms Look Like Mushrooms?" by Peter Werner, Mycena News, December 2002. (Archived at MycoWeb)
• "Mycomorphology Part 2: Basidiocarp Keeps its Balance" by Peter Werner, Mycena News, March 2003. (Archived at MycoWeb)