Wikipedia
Myxogastria (myxogastrids, ICZN) or Myxomycetes ( ICBN), is a class of Myxogastria, itself a grouping of slime moulds, that contains 5 orders, 14 families, 62 genera and 888 species. They are colloquially known as the plasmodial or acellular slime moulds.
All species pass through several, very different morphologic phases, such as microscopic individual cells, slimy amorphous organisms visible with the naked eye and conspicuously shaped fruit bodies. Although they are monocellular, they can reach immense widths and weights: in extreme cases they can be up to across and weigh up to .
The class Myxogastria is distributed worldwide, but it is more common in temperate regions where it has a higher biodiversity than in polar regions, the subtropics or tropics. They are mainly found in open forests, but also in extreme regions such as deserts, under snow blankets or underwater. They also occur on the bark of trees, sometimes high in the canopy. These are known as corticolous myxomycetes. Most species are very small.