The detection of four major clades and new species from China with elongated cheilocystidia: A contribution to the genus Mallocybe (Inocybaceae, Agaricales)

Abstract

Mallocybe is a newly elevated genus of the ectomycorrhizal mushroom family, Inocybaceae, based on Inocybe subg. Mallocybe. Although new species in this genus have constantly been discovered worldwide during the past decades, species native to China is poorly documented. Moreover, as a characteristic feature, members of this genus often have phaseoliform basidiospores and short catenated cheilocystidia. Therefore, this study describes three new Chinese Mallocybe species with elongated cheilocystidia through morphological and molecular analyses. Of the identified species, while M. pallidipes was collected from Populus in northeastern China, M. aurantiodisca was discovered in subtropical evergreen broad-leaved forests dominated by Castanopsis in the Zhejiang Province, and M. longsicystis was discovered under fagaceous forests in tropical and subtropical China. From the multi-gene phylogenetic analysis, four major clades were also elucidated in the genus, of which three new species were grouped with three North American species in a full support clade. Finally, we discussed the systematic position of the new species and the genus's infrageneric phylogeny.