Teleomorph, anamorph and holomorph

In mycology, the terms teleomorph, anamorph, and holomorph apply to portions of the life cycles of fungi in the phyla Ascomycota and Basidiomycota:

Fungi are classified primarily based on the structures associated with sexual reproduction, which tend to be evolutionarily conserved. However, many fungi reproduce only asexually, and cannot be easily placed in a classification based on sexual characters; some produce both asexual and sexual states. These problematic species are often members of the Ascomycota, but a few of them belong to the Basidiomycota. Even among fungi that reproduce both sexually and asexually, often only one method of reproduction can be observed at a specific point in time or under specific conditions. Additionally, fungi typically grow in mixed colonies and sporulate amongst each other. These facts have made it very difficult to link the various states of the same fungus.

Fungi that are not known to produce a teleomorph were historically placed into an artificial phylum, the "Deuteromycota", also known as "Fungi Imperfecti", simply for convenience. Some workers hold that this is an obsolete concept, and that molecular phylogeny allows accurate placement of species which are only known from part of their life cycle. Others retain the term deuteromycetes, but give it a lowercase "d" and no taxonomic rank.

Historically, Article 59 of the International Code of Botanical Nomenclature permitted mycologists to give asexually reproducing fungi (anamorphs) separate names from their sexual states (teleomorphs) but this practice was discontinued as of 1 January 2013.

The dual naming system can be confusing for novices. It is essential for workers in plant pathology, mold identification, medical mycology, and food microbiology, fields in which asexually reproducing fungi are commonly encountered.

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