Two New Species of Collybiopsis (Omphalotaceae, Agaricales) from Southwestern Guizhou, China

Abstract Two new species of Collybiopsis, Co. guizhouensis and Co. anlongensis, are described from southwestern Guizhou Province, China, based on morphological and multi-gene phylogenetic analyses (internal transcribed spacer (ITS), nuclear large subunit ribosomal DNA (nrLSU), and translation elongation factor 1-α (tef1-α)). Phylogenetic analyses (ML/BI) of the combined ITS–nrLSU–tef1-α dataset placed each species within a distinct and well-supported clade: Co. guizhouensis (ML-BP = 100%; BI-PP = 0.94) and Co. anlongensis (ML-BP = 100%; BI-PP = 1.00). These molecular results, together with morphological distinctions, support their recognition as new species.