The plasmodiophores[1] (also known as plasmophorids[2] or plasmodiophorids[3]) are a group of obligate endoparasitic protists belonging to the subphylum Endomyxa in Cercozoa.

[9] In 1892, Engler placed the family in its own class “Plasmodiophorales”, later renamed “Plasmodiophoromycetes” to fit nomenclature standards.

[10] In 1969 Whittaker, in his five-kingdom system, elevated the group to a separate phylum “Plasmodiophoromycota”, acknowledging them as protists instead of fungi.

[1] In 1993 Cavalier-Smith included the plasmodiophores and their sister group Phagomyxida in their current class, Phytomyxea, as part of a polyphyletic phylum called Opalozoa, which at the time contained a diverse assemblage of unrelated zooflagellates, opalines and proteomyxids.

[12] Finally, after phylogenetic analyses, in 2002 Cavalier-Smith placed all Phytomyxea, including plasmodiophores, in the subphylum Endomyxa, inside the rhizarian phylum Cercozoa.