A basidiospore is a reproductive

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

produced by Basidiomycete

fungi A fungus (plural, : fungi or funguses) is any member of the group of Eukaryote, eukaryotic organisms that includes microorganisms such as yeasts and Mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified ...

, a grouping that includes mushrooms, shelf fungi,

rusts Rust is an iron oxide, a usually reddish-brown oxide formed by the reaction of iron and oxygen in the catalytic presence of water or air moisture. Rust consists of hydrous iron(III) oxides (Fe2O3·nH2O) and iron(III) oxide-hydroxide (Fe ...

, and

smut Smut may refer to: * Smut (fungus), a group of plant parasitic fungi * ''Smut'' (comics), an adult British comic title dating back to the 1980s * A colloquial term for obscenity in general or pornography Pornography (often shortened to po ...

s. Basidiospores typically each contain one

haploid Ploidy () is the number of complete sets of chromosomes in a cell (biology), cell, and hence the number of possible alleles for Autosome, autosomal and Pseudoautosomal region, pseudoautosomal genes. Sets of chromosomes refer to the number of mat ...

nucleus that is the product of meiosis, and they are produced by specialized fungal cells called basidia. Typically, four basidiospores develop on appendages from each basidium, of which two are of one strain and the other two of its opposite strain. In gills under a cap of one common species, there exist millions of basidia. Some gilled mushrooms in the order Agaricales have the ability to release billions of spores. The puffball fungus '' Calvatia gigantea'' has been calculated to produce about five trillion basidiospores. Most basidiospores are forcibly discharged, and are thus considered ballistospores. These spores serve as the main air dispersal units for the fungi. The spores are released during periods of high humidity and generally have a night-time or pre-dawn peak concentration in the atmosphere. When basidiospores encounter a favorable substrate, they may germinate, typically by forming

hyphae A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one or ...

. These hyphae grow outward from the original spore, forming an expanding circle of mycelium. The circular shape of a fungal colony explains the formation of fairy rings, and also the circular lesions of skin-infecting fungi that cause ringworm. Some basidiospores germinate repetitively by forming small spores instead of hyphae.

General structure and shape

Basidiospores are generally characterized by an attachment peg (called a

hilar appendage Hilum may refer to: * Hilum (anatomy), a part of an organ where structures such as blood vessels and nerves enter the body * Hilum (botany), a scar on a seed or spore created by detachment See also * Fovea (disambiguation), another term associa ...

) on its surface. This is where the spore was attached to the basidium. The hilar appendage is quite prominent in some basidiospores, but less evident in others. An apical germ pore may also be present. Many basidiospores have an asymmetric shape due to their development on the basidium. Basidiospores are typically single-celled (without septa), and typically range from spherical to oval to oblong, to ellipsoid or cylindrical. The surface of the spore can be fairly smooth, or it can be ornamented. The color of the spore print is usually found in the spore wall, although in rare instances – like the yellow spores of ''

Clavaria helicoides ''Clavaria'' is a genus of fungi in the family Clavariaceae. Species of ''Clavaria'' produce basidiocarps (fruit bodies) that are either cylindrical to club-shaped or branched and coral-like. They are often grouped with similar-looking species f ...

'' – the

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. ...

is responsible for the spore color.

References

Tree of Life: Basidiomycota

Basidiospores
Basidiomycota Fungal morphology and anatomy Mycology {{Basidiomycota-stub