The Club Fungi, or Basidiomycetes, are one of the commonly recognized groups of true fungi, and form a monophyletic group of fungi. This group includes the mushrooms and toadstools, as well as shelf fungi, coral fungi, jelly fungi, stink horns, rusts, smuts, earth stars, and fairy rings. These fungi are major decomposers of plant leaf litter in moist and forested systems, especially with their ability to decompose the lignin in wood. They are found in practically every terrestrial ecosystem, as well as freshwater and marine habitats. Many form mutualistic relationships with the roots of plants (mycorrhizae), but others are parasitic on plants, such as the rusts/smuts.
- Geologic Age: Devonian - present
└Unikonts: fungi, slime molds, animals└Basidiomycota
- Diversity: Group with about 25,000 species
- Examples include mushrooms, toadstools, shelf fungi, coral fungi, jelly fungi, stink horns, rusts, smuts, earth stars, and fairy rings
- Ecology and Form
- Major decomposers of plant litter
- The body of a fungus are aggregated hair-like strands called mycelium (plural = mycelia), which creeps along the ground releasing enzymes and digesting plant material for energy.
- Basidiomycete mycelium have crosswalls (=septate), and the crosswalls are perforated
- In their "vegetative" feeding phase, the mycelia are monokaryotic, in which they have 1 nucleus per cell, which is typical of most eukaryotes. During reproduction, these fungi become dikaryotic, in which they have 2 nuclei per cell. See Life Cycle below for more details.
- Clamp connections connect two cells and allow accurate segregation of nuclei during mitosis and growth
- Life cycle: club fungi can reproduce both sexually and asexually
- Basidiomycetes exhibit a complex, haplontic life cycle
Below: life cycle of basidiomycetes
- Sexual reproduction in club fungi begins when monokaryotic mycelia strands come in contact with mycelia from another individual
- The tips of the mycelia, from each organism, fuse together. This creates new cells that combine the protoplasm and organelles of both organisms, but the nuclei do not fuse. This is a process called plasmogamy, and creates cells with two nuclei (=dikaryotic or binucleate)
- From these fused cells, these two organisms will begin to produce a large fruiting body, called a basidiocarp, such as a mushroom. This basidiocarp continues to grow and mature creating areas of fertile tissue, such as the gills on a mushroom.
Above: click to see the growth of a basidiocarp
- Along the edge of the gills are special cells called basidia (singular = basidium). Inside these cells, the two nuclei fuse to form a diploid zygote. This is called karyogamy, and completes fertilization.
Above: diagram of a basidum
- The diploid zygote will then go through meiosis to produce four haploid spores. These spores are then dispersed into nature
- The spores then germinate into monokaryotic mycelia
“Hymenomycetes” - Class Basidomycetes, e.g. Coprinus or Agaricus
Above: Fairy ring around a pine treeAbove: Cap fungus or toadstool (Amanita) basidiocarpAbove: Jelly fungus (Dacrymyces) basidiocarp
"Gasteromycetes” - Class Basidomycetes
Above: Stink horn (Phallus) basidiocarpBelow: Puffball basiocarpAbove: Earth star (Geastrum) basidiocarp
Below: Bird's nest fungus (Cyathus) basidiocarp
Rust/Smuts - Classes Teliomycetes and Ustomycetes
- Rusts (Teliomycetes) ~7,000spp.; Smuts (Ustomycetes), ~1,070spp., e.g. Puccinia
- Tremendously important due to agricultural damage
- e.g. wheat rust, white pine blister, cedar-apple rust, coffee rust & peanut rust; corn smut, wheat bunt smut
- Do not form basidioma, but possess dikaryotic hyphae and basidia
- Extremely complex lifecycle
- Heteroecious: require two different hosts
- Autoecious: require one different hosts
Above: white pine blister rust (Cronartium)