Abstract
The Amanita subgenus Amanitina contains six sections, and the species diversity of this subgenus has still not been explored in Thailand. Twenty samples collected in 2019 and 2020, which had the morphological characteristics of the Amanita subgen. Amanitina, were observed in this study. Both the microscopical characteristics and multi-gene phylogenetic analyses of the ITS, nrLSU, RPB2, TEF1-α, and TUB gene regions revealed that the 20 samples represented nine species and dispersed into four sections. Remarkably, three taxa were different from any other currently known species. Here, we describe them as new to science, namely A. albifragilis, A. claristriata, and A. fulvisquamea. Moreover, we also recognized six interesting taxa, including four records that were new to Thailand, viz. A. cacaina, A. citrinoannulata, A. griseofarinosa, and A. neoovoidea, as well as two previously recorded species, A. caojizong and A. oberwinkleriana. Moreover, we provide the first RPB2 and TEF1-α gene sequences for A. cacaina. Detailed descriptions, illustrations as line drawings, and comparisons with related taxa are provided.