Polythetic evidence supports the introduction of Hebeloma dipterocarpohilum sp. nov. (Hymenogastraceae, Agaricales), a lookalike of the edible H. parvisporum

Hebeloma dipterocarpohilum sp. nov. is described and illustrated based on materials collected from Northern Thailand. Microscopic characters’ drawings, basidiospores’ scanning microphotographs and pictures of the basidiomes are provided. Phylogenetic analyses based on DNA sequences of ITS and MCM7 gene regions were carried out to support species separation from the lookalike H. parvisporum. The novel species formed a well-supported clade with the closely related Hebeloma parvisporum. Micromorphologically, H. dipterocarpophilum has longer and broader cheilocystidia compared to H. parvisporum. Both species also differ in ecology, with H. dipterocarpohilum occurring in dry dipterocarp forests at elevations lower than 1,000 m a.s.l., whereas H. parvisporum is found at higher elevations, in Fagaceae-dominated forests without Dipterocarpaceae, in neighbouring Laos.