Basidiomycota
Urediniomycetes
Subdivision Ustilaginomycotina
Ustilaginomycetes
Subdivision Hymenomycotina
Homobasidiomycetes - mushrooms
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The Division
Basidiomycota is a large
taxon within the Kingdom
Fungi that includes those species that produce
spores in a club-shaped structure called a
basidium. Essentially the sister group of the
Ascomycota, it contains some 30,000 species (37% of the described fungi). The Basidiomycota was traditionally divided into
Homobasidiomycetes — the true
mushrooms — and Heterobasidiomycetes — the
rusts and
Hymenomycotina (Hymenomycetes; mushrooms), the Ustilaginomycotina (Ustilaginomycetes; true smut fungi), and the Teliomycotina (Urediniomycetes; rusts).
Basidiomycota include both unicellular (some yeasts) and multicellular forms and sexual and asexual species. They occur in terrestrial and aquatic environments (including the marine environment) and can be characterized by bearing sexual spores on
basidia, having a long-lived
dikaryon, and usually showing
clamp connections.
Basidium
The basidium (pl., basidia) is a microscopic structure found at the ends of hyphae in the fruiting bodies of basidiomycete fungi — that is, the basidium is the diagnostic feature of those fungi classified as Basidiomycota. The basidium usually bears four sexual spores called basidiospores. The word basidium literally means little pedestal, from the way in which the basidium supports the spores. However, some biologists suggest that the structure more closely resembles a club; thus, the Basidiomycota are also known as the club fungi.
Life cycle
Basidiomycetes have a peculiar sexuality.
They most often are heterothallic, but with a bipolar (unifactorial) or tetrapolar (bifactorial) mating system acting like many sexes.
Usually, somatogamy (hyphogamy) is performed.
Most basidiomycetes live out most of their life as dikaryotic (heterokaryotic) mycelium, with karyogamy and meiosis happening in the basidium.
There are examples of diploid life cycles as well: the genus Xerula was found to sometimes produce diploid clones as spores, and Armillaria, a common forest pathogen, has diploid mycelium, where karyogamy directly follows plasmogamy.
Asexual spores (
