What Are Slime Moulds
What are They
Family Menu
Species Menu
PlasmodiumMembers of this class are commonly referred to as slime moulds. These have been thought to belong to both the animal and fungi kingdoms at one time or another. It's now known that they are quite unrelated to animals and fungi, and are now classified in the Kingdom Protista.

However, slime moulds do exhibit characteristics of both fungi and animals. In the feeding stage, the slime moulds move about as a mass of protoplasm (image to the right), (the plasmodium) feeding on bacteria, spores, and other organic matter much like an amoeba. When the food supply is exhausted or other unfavourable conditions occur, the plasmodium changes, taking on the appearance of a fungus.
There are two main groups of slime moulds in the Protista Kingdom.

1 - Plasmodial slime moulds, or true slime moulds are large single-celled massas with thousands of nuclei called a plasmodium. They are formed when individual flagellated cells swarm together and fuse. The result is one large bag of cytoplasm with many diploid nuclei.

2 - Cellular slime moulds spend most of their lives as separate single-celled amoeboid protists, but upon the release of a chemical signal, the individual cells aggregate into a great swarm, known as a pseudoplasmodia, and eventually muticellular slugs.
The plasmodial stage is found in cool, shady, moist places on rotting logs, leaf litter, moist shaded soil, or other organic matter. There are around 1000 known species that feed on decaying organic matter, bacteria, protozoa, and other minute organisms, which they engulfs and digest. The plasmodium may reach several hundred millimetres in diameter and is often brightly coloured, although many are also inconspicuous.
Fruiting bodies

Life Cycle
Below is a detailed a life cycle, but not all slime moulds will follow this exactly.

1 - Once a spore is released from the fruiting body, it's dispersed, either by insects, animals, rain or air movement. On landing in a suitable location with appropriate moisture and temperature, one to four protoplasts are germinated.

2 - The protoplasts once released from the spore's wall through either a pore or fissure will be either a flagellated swarm cell if conditions are wet, or a non-flagellated myxamoebae cell in dryer conditions.

3 - If conditions for growth are not suitable, the cells can become microcysts to survive for long periods of time.

4 - A diploid zygote is formed when two compatible myxamoebae or swarm cells fuse. This is known as plasmogamy and karyogamy.

5 - After a time of feeding and growing, the zygote develops into a single-celled multinucleate structure known as a plasmodium.

6 - If environmental conditions are not suitable, then the plasmodium can change into another dormant state known as the sclerotium.

7 -
When the conditions are right, the mature plasmodium produces one to many fruiting bodies containing spores, depending on species.

Assorted plasmodiums: at this point, they are unidentifiable.
The Hidden Forest
Slime moulds