The recently described fungal phylum Entorrhizomycota was established solely for the genus
Entorrhiza, species of which cause root-galls in Cyperaceae and Juncaceae. Talbotiomyces calosporus
(incertae sedis) shares morphological characteristics and an ecological niche with species of Entorrhiza. We
investigated the higher classification of T. calosporus to determine whether it belongs in Entorrhizomycota.
Ribosomal DNA sequences showed Talbotiomyces to be a close relative of Entorrhiza and both taxa form a
highly supported monophyletic group. Based on molecular phylogenetic analyses and in congruence with
existing morphological and ecological data, Entorrhiza and Talbotiomyces represent a deep dichotomy
within the Entorrhizomycota. While species of Entorrhiza are characterised by dolipores and occur on
monocotyledons, members of Talbotiomyces are characterised by simple pores and are associated with
eudicotyledons. This expands the host range of the recently described Entorrhizomycota from Poales to
other angiosperms. Higher taxa, namely Talbotiomycetales ord. nov. and Talbotiomycetaceae fam. nov.,
are proposed here to accommodate Talbotiomyces.