|Families & genera|
The dictyosteliids are a group of protists often called cellular slime molds, which is a misnomer, since they aren't related true molds. When food is readily available, they take the form of individual amoebae, which feed and divide normally. However, when the food supply is exhausted, these aggregate in merging streams to form a pseudoplasmodium or slug. The slug is capable of migrating towards light or heat. Slugs exhibit distinct cell types in the anterior and posterior, and under the correct circumstances will mature into a fruiting body. The fruiting body consists of spores, which are inactive cells encased in a resistant cell wall, and supporting structures, mostly in the form of a stalk.
There is a definite correspondence between different parts of the slug and parts of the final stalked sporangium. As such, dictyosteliids have been of interest to those studying cellular communication and differentiation. Aggregation takes place by chemotaxis to chemicals produced by other amoebae, notably cAMP. Dictyosteliid amoebae move using filose pseudopods, and appear particularly closely related to the Acanthamoebida and Stereomyxida.