Editing Basidiomycota (section)

===Rusts===
[[rust (fungus)|Rusts]] ([[Pucciniales]], previously known as [[Uredinales]]) at their greatest complexity, produce five different types of spores on two different host plants in two unrelated host families. Such rusts are heteroecious (requiring two hosts) and macrocyclic (producing all five spores types). Wheat [[stem rust]] is an example. By convention, the stages and spore states are numbered by [[Roman numerals]]. Typically, basidiospores infect host one, also known as the alternate or sexual host, and the mycelium forms [[pycnidia]], which are miniature, flask-shaped, hollow, submicroscopic bodies embedded in the host tissue (such as a leaf). This stage, numbered "0", produces single-celled spores that ooze out in a sweet liquid and that act as nonmotile [[spermatia]], and also protruding [[receptive hyphae]]. [[Insect]]s and probably other [[Vector (epidemiology)|vectors]] such as rain carry the spermatia from spermagonium to spermagonium, cross inoculating the mating types. Neither thallus is male or female. Once crossed, the dikaryons are established and a second spore stage is formed, numbered "I" and called [[aecia]], which form dikaryotic [[aeciospore]]s in dry chains in inverted cup-shaped bodies embedded in host tissue. These aeciospores then infect the second host, known as the primary or asexual host (in macrocyclic rusts). On the primary host a repeating spore stage is formed, numbered "II", the [[urediospore]]s in dry pustules called [[uredinia]]. Urediospores are dikaryotic and can infect the same host that produced them. They repeatedly infect this host over the growing season. At the end of the season, a fourth spore type, the [[teliospore]], is formed. It is thicker-walled and serves to overwinter or to survive other harsh conditions. It does not continue the infection process, rather it remains dormant for a period and then germinates to form basidia (stage "IV"), sometimes called a [[promycelium]]. In the Pucciniales, the basidia are cylindrical and become 3-[[septum|septate]] after meiosis, with each of the 4 cells bearing one basidiospore each. The basidiospores disperse and start the infection process on host 1 again. [[Autoecious]] rusts complete their life-cycles on one host instead of two, and microcyclic rusts cut out one or more stages.{{cn|date=January 2024}}