The Collaborative International Dictionary of English v.0.48:

Myxomycota \Myxomycota\ n. (Biol.)
   The slime molds; organisms having a noncellular and
   multinucleate creeping vegetative phase and a propagative
   spore-producing stage: comprises Myxomycetes and
   Acrasiomycetes and Plasmodiophoromycetes; in some
   classifications placed in the kingdom Protoctista.

   Syn: division Myxomycota, Gymnomycota, division Gymnomycota.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Myxomycota
    n 1: slime molds; organisms having a noncellular and
         multinucleate creeping vegetative phase and a propagative
         spore-producing stage: comprises Myxomycetes and
         Acrasiomycetes; in some classifications placed in the
         kingdom Protoctista [syn: Myxomycota, division
         Myxomycota, Gymnomycota, division Gymnomycota]