AbstractMyxogastria (also called Myxomycetes or plasmodial slime‐moulds) are mostly known through their usually conspicuous fruiting bodies. Another unifying trait is the presence of a facultative flagellate stage along with the obligate amoeboid stage. Here we show with two‐gene phylogenies (SSU rRNA and EF‐1alpha genes) that the incertae sedis, non‐flagellate Echinosteliopsis oligospora belongs to the dark‐spore clade (Fuscisporidia) of the Myxogastria. In addition, we confirm that Echinostelium bisporum, firstly described as a protostelid, belongs to the Echinosteliida, which are divided into three major clades and are paraphyletic to the remaining Fuscisporidia.