Purpureocorticium microsporum (Basidiomycota) gen. et sp. nov. from East Asia

A corticioid fungal species found in mountainous Taiwan, and Yunnan Province of China, is described as a new genus and new species: Purpureocorticium microsporum (Agaricomycetes, Basidiomycota). Morphological study and phylogenetic analyses based on sequence data respectively derived from the large subunit nuclear ribosomal RNA gene (LSU nrDNA) alone and the combined dataset of LSU nrDNA and translation elongation factor 1-α gene (tef1-α) indicated that Purpureocorticium does not belong to any clade of the Agaricomycetes. Purpureocorticium and P. microsporum are characterized by having a resupinate basidiocarp with smooth hymenial surface which turns purple in KOH, and becomes purplish after storage, microscopically having compact texture of subiculum, nodose-septate thin-walled generative hyphae, absence of cystidia, basidia subclavate with a median constriction, or utriform, bearing ovate-ellipsoid small-sized basidiospores, which are smooth and thin-walled, inamyloid, and nondextrinoid. The new combination Rhizochaete rubescens is proposed, based on morphological and phylogenetic evidences.