Slime moulds are not fungi, but in the past they were generally treated as such and included in the kingdom of Fungi. Many were grouped under the heading 'myxomycetes', and many books about fungi still include a short section describing, with illustrations, some of the more common slime moulds. We are doing so here not to perpetuate the taxonomic inaccuracy but because many people find slime moulds and ask us to help identify the strange 'fungi' they have photographed.
The slime moulds (spelt molds in America) are not a monophyletic group but at least three very different groups of organisms, sometimes collectively placed under the heading Eumycetozoa. Nowhere near as plentiful as fungi species (which run in to millions worldwide), slime mould species known to science certainly number in excess of 1000.
The name 'slime mould' refers to just one phase of the life cycle of some (but not all) of the organisms in this group when they take the form of a gelatinous slime. When conditions become unfavourable for them continuing in the 'slimes' stage, slime moulds form sporangia, which are essentially clusters of spores. Sporangia are often borne upon the tips of slender stalks. When spores from the sporangia are carried by wind, water or animals to new habitats, they may 'germinate to produce new amoebae, and so the life cycle of the slime mould is repeated..
When they have access to plenty of food, those slime moulds belonging to the grouping Amoebozoa (the largest group of slime moulds and the kinds most likely to be seen by a casual walker in the countryside) generally live as separate single-celled organisms; however, when food (in the form of bacteria, fungal yeasts and other microorganisms that live on decaying plant matter) becomes scarce many individual slime mould organisms may group together and start moving en masse in search of food - quite an unsettling sight if you are of a nervous disposition! In this state they are easy to spot, and they are often found on grass or humus-rich soil and, in particular, on damp rotting logs in shady woodland settings.
If you have taken pictures of beautiful, unusual or just plain weird slime moulds and would be willing to have them shown on the First Nature website (with proper acknowledgement of you as the photographer, of course) to help other people learn more about and enjoy these fascinating organisms, please see our Contributors guide...
This page includes picture content kindly contributed by Pippa Cottrell, Gerald Gladstone, Simon Harding, David Kelly, Sarah Perkins and Kayley Priestley.
If you have found this information helpful, please consider helping to keep First Nature online by making a small donation towards the web hosting and internet costs.
Any donations over and above the essential running costs will help support the conservation work of Plantlife, the Rvers Trust and charitable botanic gardens - as do author royalties and publisher proceeds from Pat and Sue's nature books - available from First Nature...