The species Pirex concentricus was originally described by Mordecai Cubitt Cooke and Job Bicknell Ellis in 1885 as Radulum concentricum. Ellis collected the type specimens from Oregon.[4] A century after Cooke's publication, Kurt Hjortstam and Leif Ryvarden circumscribed the new genus Pirex to contain this fungus, as they believed it to have a unique combination of traits that would not adequately fit into any other known genera. The name Pirex is an anagram of the fungal genus Irpex.[5]
In 1995, Hjortstam considered Pirex to be a synonym of Pseudolagarobasidium, and proposed the new combinationPseudolagarobasidium concentricum. Modern systematics considers the two genera to be distinct;[6]Pseudolagarobasidium is classified in the family Phanerochaetaceae. Hjortstam added Hydnum subvinosum Berk. & Broome to Pirex in 1987,[7] but this fungus is considered now a species of Radulodon.[8]
^Hallenberg, Nils; Ryberg, Martin; Nilsson, R. Henrik; Wood, Alan R.; Wu, Sheng-Hua (2008). "Pseudolagarobasidium (Basidiomycota): on the reinstatement of a genus of parasitic, saprophytic, and endophytic resupinate fungi". Canadian Journal of Botany. 86 (11): 1319–1325. doi:10.1139/B08-088.
^Hjortstam, K. (1987). "A check-list to genera and species of corticioid fungi (Hymenomycetes)". Windahlia. 17: :55–85.