All known members fruit, either sorocarpically (Dictyostelia), or sporocarpically (Myxogastria, Protosporangiida); with a life cycle having a single haploid amoeboid state (Dictyostelia); or a life cycle with a bikont ciliated amoebae state that gives rise to a non-ciliate obligate amoeboid state from which sporocarps develop (Myxogastria and Protosporangiida); ciliated amoebae of myxogastrids and protosporangiids and amoebae of dictyostelids flat and form wide pseudopodia with acutely pointed subpseudopodia and no pronounced streaming of the granular cytoplasm; where sex is well studied, the zygote cannibalizes haploid amoebae.
These are true slime molds, divided into the myxomycetes, dictyostelids, and protostelids. The myxomycetes are plasmodial slime molds. These fungus-like organisms have a life cycle that involves two very different trophic (feeding) stages: uninucleate amoebae, with or without flagella, and plasmodia.
A plasmodium is a distinctive multinucleate structure that typically occurs in cool, moist, shady places like stumps and leaf litter on the forest floor. Under favorable conditions, the plasmodium gives rise to one or more fruiting bodies containing spores that are for most species dispersed by the wind and complete the life cycle by germinating to produce the uninucleate amoeboflagellate cells.
There are approximately 1000 recognized species of myxomycetes.