A. Life Cycle
The myxomycete life cycle (Fig.2.4) encom-
passes two very different trophic stages, one
consisting of uninucleate amoebae, with or
without flagella, and the other consisting of a
distinctive multinucleate structure, the plasmo-
dium (Martin et al. 1983 ). Much of what isFig. 2.4Generalized life cycle in myxomycetes. (a,b)
A protoplast emerges from the spore. (c) The proto-
plast can take the form of an amoeba or a flagellated cell
(the term amoeboflagellate refers to both forms) during
the first trophic stage. (d) Under dry conditions or in
the absence of food, an amoeboflagellate forms a
microcyst, or resting stage. (e–g) Compatible amoebo-
flagellates fuse to form a zygote (g). (h–j) The nucleus
of the zygote divides by mitosis (h), and each
subsequent nucleus also divides without being followed
by cytokinesis, thereby producing a single large cell (j),
the plasmodium, that represents the second trophic
stage. Under adverse conditions, the plasmodium can
form the second type of resting stage found in myxo-
mycetes, the sclerotium (i). (k,l) Fruiting bodies are
formed from the plasmodium. During fruiting body
formation, spores are produced. Adapted from
Stephenson ( 2003 )28 S.L. Stephenson