Genus Pentarhizidium

Monophyletic (Gastony & Ungerer, 1997; Rothfels et al., 2012a). The name Pentarhizidium was first used in 1927, in the context of describing the morphological distinctiveness of the P. orientale stele (Hayata, 1927). However, the paper lacked a description of the genus itself and we consider Pentarhizidium and P. orientale as nomina nuda until the genus was formally described and a type (P. japonicum) was designated (Hayata, 1928).