fungi mushrooms mycology the fifth kingdom

Are Slime Moulds Really Fungi?

Are Slime Moulds really Fungi?

No, slime moulds are not fungi. They are members of the Kingdom Protozoa. They used to be included among the fungi because people found their dry fruiting structures in the woods when they were out collecting fungi.

In fact, the most characteristic structure of a slime mould is a plasmodium -- a giant amoeba with thousands of nuclei in a single mass of protoplasm. This plasmodium moves around slowly in decaying organic matter or the soil, eating - swallowing up or ingesting -- bacteria and other tiny particles of organic matter.

No true fungus 'eats' in this way. All fungi have to absorb their food.

When the giant amoeba has accumulated enough food reserves, or when the weather gets cold or dry, the plasmodium will undergo an amazing change, turning from a slimy, slowly undulating mass into a series of small, dry fruiting bodies which contain powdery spores.

After they have been dispersed, each of these spores will germinate and release a tiny amoeba which, if it successfully finds and mates with another amoeba, can then begin to feed and develop into a new plasmodium.

Slime moulds used to be called Myxomycetes, but this name implied that they were a kind of fungus, so they are now called Myxostelida, which is one of many Phyla in the Kingdom Protozoa.

[Remember that we now recognize seven Kingdoms.
There are two prokaryotic Kingdoms: Archaebacteria and Eubacteria.
There are five eukaryotic Kingdoms: Plantae, Animalia, Eumycota (Fungi), Chromista (Stramenopila), and Protozoa.]

To see some pictures of Myxostelida, go to Chapter 2a.

For a more detailed account, refer to Chapter 2 of the book The Fifth Kingdom

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