Any of various small simple eukaryotic organisms that live in damp terrestrial habitats and superficially resemble fungi, to which they are unrelated. They are often seen as slimy masses on rotting wood and show amoeboid movement, feeding by ingesting small particles of food. They exist either as free cells (myxamoebas) or as multinucleate aggregates of cells depending on the stage of the life cycle. When conditions become unfavourable, slime moulds form fruiting bodies (sporangia), from which spores are released. These disperse and subsequently germinate into small amoebas, thereby completing the life cycle. The classification of slime moulds has long been contentious. Modern molecular systematics identifies several distinct groups. Plasmodial slime moulds live as ‘giant cells’ (see plasmodium), formed by the fusion of individual flagellated cells and containing many nuclei. They fall into two groups: Myxogastria and Protostelia. Cellular slime moulds live mainly as separate amoeboid cells but aggregate to form a cellular swarm called a pseudoplasmodium, in which the plasma membranes of individual cells are retained. There are two groups: the Dictyostelida, which, like the plasmodial slime moulds, are included in the amoebozoans; and the acrasid slime moulds (Acrasidae), which belong to the excavates. Another unrelated group, the Labyrinthomycota, consists of the slime nets, protists that secrete filaments along which the cells glide.
Subjects: Chemistry — Biological Sciences.