Myxomycota

Abstract

The taxonomic division Myxomycota is made up of those eukaryotic microorganisms commonly referred to as the true slime moulds or (as they are known to biologists) myxomycetes. Since their discovery, myxomycetes have been variously classified as plants, animals or fungi. However, there is now abundant molecular data to confirm that they are amoebozoans and not fungi. Myxomycetes are usually present and sometimes abundant in terrestrial ecosystems, where they are associated with various types of decaying plant materials (e.g. coarse woody debris and forest floor litter). Because they produce aerial spore‐bearing structures that resemble those of certain fungi and also typically occur in some of the same types of ecological situations as fungi, myxomycetes have been traditionally studied by mycologists, and this continues to be the case in most instances. For example, the myxomycetes are still included in many textbooks of fungi.

Key Concepts

  • Since their discovery, myxomycetes have been variously classified as plants, animals or fungi, but there is now abundant molecular data to confirm that they are amoebozoans and not fungi.
  • Because they produce aerial spore‐bearing structures that resemble those of certain fungi and also typically occur in some of the same types of ecological situations as fungi, myxomycetes have been traditionally studied by mycologists, and this continues to be the case.
  • Approximately 900 species of myxomycetes have been described, but the concept of species as used for many of the more familiar groups of organisms is often rather problematic.
  • Molecular data indicate that the myxomycetes consist of two main assemblages, the light‐ and the dark‐spored myxomycetes.
  • Myxomycetes have been recorded from every major type of terrestrial ecosystem examined to date, and at least a few species have been recovered from aquatic habitats microorganisms.

Keywords: amoebozoans; dark‐spored clade; ecology; fruiting body; light‐spored clade; morphospecies; myxomycetes; taxonomy

Figure 1. Myxomycete life cycle. A. Spore. B. Germinating spore. C. Uninucleate amoeboflagellate stage, with (right) or without (left) flagella. D. Microcyst. E and F. Fusion of two compatible amoeboflagellates to produce a single cell. G. Zygote. H. Early plasmodium. I. Sclerotium (derived from the plasmodium only under adverse conditions). J. Portion of a mature plasmodium. K. Beginning of the formation of fruiting bodies. L. Mature fruiting bodies with spores still enclosed. Adapted from Stephenson 2011 © Mushroom Research Foundation.
Figure 2. Myxomycete plasmodium. Image produced by Randy Darrah.
Figure 3. Types of fruiting bodies found in the myxomycetes. (a). Sporangium. (b). Plasmodiocarp. (c). Pseudoaethalium. (d). Aethalium. Image produced by Randy Darrah.
Figure 4. Basic structural components of the fruiting body of a myxomycete. A. Hypothallus. B. Spores. C. Peridium. D. Capillitium. E. Columella. F. Stalk. Adapted from Stephenson 2003 © Landcare Research.
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Further Reading

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Stephenson SL (2003) Myxomycetes of New Zealand. Hong Kong: Fungal Diversity Press.

Stephenson SL (2010) The Kingdom Fungi: The Biology of Mushrooms, Molds, and Lichens. Portland, Oregon: Timber Press.

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How to Cite close
Stephenson, Steven L, and Darrah, Randy G(Apr 2017) Myxomycota. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0027205]