Hyphomycetes

Hyphomycetes are a form-class of Fungi, part of what has often been referred to as Fungi imperfecti, Deuteromycota, or anamorphic fungi. Hyphomycetes lack closed fruiting bodies, and are often referred to as moulds (or molds). Most hyphomycetes are now assigned to the Ascomycota, on the basis of genetic connections made by life-cycle studies or by phylogenetic analysis of DNA sequences; many remain unassigned phylogenetically. Identification of hyphomycetes is primarily based on microscopic morphology including: conidial morphology, especially septation, shape, size, colour and cell wall texture, the arrangement of conidia as they are borne on the conidiogenous cells (e.g. if they are solitary, arthrocatenate, blastocatenate, basocatenate, or gloiosporae), the type conidiogenous cell (e.g. non-specialized or hypha-like, phialide, annellide, or sympodial), and other additional features such as the presence of sporodochia or synnemata.^{[1] [2] [3]}

Taxonomic and nomenclatural history

Because asexual forms of fungi usually occur separately from their sexual forms, when microscopic fungi began to be studied in the early 19th century, it was often unknown when two morphologically different forms were actually part of one species. The tendency for some organisms to apparently only have asexual forms, or for their sexual forms to be discovered long after the asexual forms, meant that an independent taxonomy was developed for asexual fungi. Near the beginning of the 20th century, when it became clearer that many asexual and sexual forms were related, the concept of 'form taxa' was developed. The independent taxonomy of asexual forms was regarded as artificial, not representative of evolutionary relationships, and intended to be practical for identification purposes. The taxonomy of the sexual states was considered the true classification. The result was that many fungal species ended up with two accepted Latin binomials, one for the asexual form (or anamorph) and the other for the sexual form (teleomorph). This dual nomenclature was only abandoned in January 2012, and the transition to a single name system, with one name representing all morphs of a fungus, is still incomplete.

Ecological importance

• Common on submerged decaying leaves and other organic matter – Particularly in clean running water – Good aeration • Branched septate mycelium – Spreads through leaf tissue • Conidiophores – Project into the water – Bear conidia • Usually branched tetraradiate structures • Important role in the breakdown of organic matter in rivers – Leaf litter falls into river – Colonised and conditioned by fungi • Mycelium spreads over surface and penetrates leaf • Extra-cellular enzymes break down leaf tissue • Leaf tissue made more palatable to invertebrates • Leaves with fungi (conditioned) are a more nutritious source of food than unconditioned leaves • Hyphomycete fungi increase the food value of leaves in the aquatic environment

See also

References

External links

Wikispecies has information related to: Hyphomycetes

• http://www.generaofhyphomycetes.org
• http://www.mycology.adelaide.edu.au/Fungal_Descriptions/Hyphomycetes_(hyaline)/
• http://www-biol.paisley.ac.uk/bioref/Fungi/Botrytis_cinerea.html

Literature

• Keith A. Seifert, Gareth Morgan-Jones, Walter Gams, Bryce Kendrick: The Genera of Hyphomycetes. Issue 9 of CBS Biodiversity Series, ISSN 1571-8859. CBS-KNAW Fungal Biodiversity Centre, 2011. ISBN 9789070351854.