Systematics of fungi

Modern fungal systematics is based upon analysis of a plethora of different genes, but morphology and ultra-structure in the hyphal cells are also important.

Below you will find an overview of recognized phyla. You can either use the interactive presentation, where you can  zoom into each phylum and find inforamtion about the phylum-characteristics and pictures of representatives. Or you can find the same information in plain text below.

 

Phylum Basidiomycota (club fungi) is the next most species rich phylum in the fungal kingdom. Here we find the majority of the fungi with conspicuous fruit bodies, such as gill fungi, boletes, puffballs, bracket fungi, chanterelles and jelly fungi, but also plant parasites without basidiocarps such as rust and smut fungi. Like Ascomycota the hyphae are septated, but the spores are sited on stalks (sterigmata) on a club formed basidium. The ecological span is great: plant (seldom animal) parasites, saprotrophes and mycorrhiza – but lichens are very rare.

Phylum Ascomycota (sac fungi) is the most species rich and variable phylum in the fungal kingdom. Here we find yeasts, moulds, plant parasites, lichens, cup fungi, morels, truffles etc. The hyphae are septated. The sporangium is a sac formed ascus. Mitospores are common and dominating in many groups. Except for the yeasts and some plant parasites, Ascomycota forms ascocarps, which can be small as in the majority of plant parasites or conspicuous as in cup fungi, morels and truffles. The ecological span is enormous, such as parasites on plants and animals, saprotrophes, mycorrhiza builders and lichens.

Phylum Mucoromycota (pin moulds) this phylum is a part of the former Zygomycota (zygote fungi) which is polyphyletic and now divided into two phyla. The fungi of both phyla have immotile spores and no flagellate stages. The mycelium is prominent, but unseptated. The sexual process produces a zygosporangium, usually serving as a resting “spore”. Mitospores are very common and often produced inside globose sporangia as we can see in the common grey pin moulds on bread or jam. Mucoromycota comprises saprotrophes in soil, plant remains or food, occasionally parasites. Some few species of Mucoromycota form ectomycorrhizal, viz. the small, truffle-like Endogone. The order Glomales is ecologically important since all species form arbuscular mycorrhiza with green plants. Many grasses (Poaceae) have this kind of mycorrhiza. Arbuscular mycorrhiza is possibly not so prominent in arctic and alpine climate compared with e.g. temperate regions, but may be overlooked.

Phylum Zoopagomycota (insect moulds) share many of the above mentioned characteristics, but forms its own phylum. Earlier it was classified in Zygomycota (no longer valid). All species are parasites on insects or other small invertebrates, or even amphibia (frogs e.g.) in their digestion tract.

The genus Olpidium is odd because it appear related to Zoopagomycota, but has flagellated spores and is unicellular.

Phylum Blastocladiomycota is reminiscent Chytridiomycota, but deviates by its life cycle featuring a haploid gametophyte and a diploid sporophyte (unique in the fungal kingdom). They live in fresh water as saprotrophes or parasites on plants and invertebrates. The simple hyphal structure has no septa, but can be unicellular.

Phylum Chytridiomycota (chytrids) is often considered as the most basal fungal group. The fungi have flagellated spores (zoospores) and gametes, a characteristic that is considered primitive in the fungal kingdom. They are unicellular or produce a slight mycelium without septa. Most species live in fresh water, either as saprotrophes on dead plants, algae and animals, or as parasites on plants and animals. Many are, however, also found in soil.

Phylum Neocallimastigomycota (rumen fungi) is similar to Chytridiomycota, but the fungi are anaerobic, lack mitochondria, and live inside the gastrointestinal tract of herbivore mammals, where they break down cellulose or hemicellulose.

Phylum Cryptomycota is unicellular or few celled fungi that are intracellular parasites on algae, even planktonic, or Blastocladiomycota and other simple fungi.

Phylum Microsporidia comprises unicellular intracellular animal parasites without mitochondria. Based on molecular phylogeny this phylum is now classified in the fungal kingdom. Earlier they were classified as protozoans. Their relation to other fungi is still disputed, although some claim that it is a sister group to Cryptomycota.

Phylum Aphelida is a very basal group comprising single celled parasites on algae. Still little is known about this group.

 

Figure from a study published in 2011 , showing what the authors call supernetwork summarizing the eight fungal backbone trees. The full study can be found at doi:10.1093/molbev/msr285