Phylogeny and taxonomic revision of Hygrophorus robustus (Hygrophoraceae, Agaricales) from southwestern China

Hygrophorus robustus was originally described from Yunnan province, China. This taxon is characterized by its robust basidiomata, salmon buff lamellae, tapered toward the base of the stipe, the odor of Tricholoma matsutake, the absence of cystidia and clamp connections, and a symbiotic association with Castanopsis delavayi. In this study, the phylogenetic position of this taxon is inferred by molecular phylogenetic analysis based on DNA sequences of internal transcribed spacer (ITS). The ITS result showed that it is nested within the genus Tricholoma and is affiliated with the North American T. grave. The morphological anatomy of this species also shows that its characteristics fit the concept of the genus Tricholoma, such as regular lamellar trama. Thus, H. robustus should be taxonomically transferred to Tricholoma, and the name of the new combination should be T. robustum. However, this name was used in the genus as Tricholoma robustum (Alb. & Schwein.) Ricken. Thus, we propose a new name T. aurantiophyllum for H. robustus.