Two New Amanita Species in Section Amanita from Thailand

Based on a survey of macro-fungi in northern and northeastern Thailand, nine samples collected in 2020 are identified as Amanita and introduced here as two new species, Amanita kalasinensis and A. ravicrocina. Typical macro- and microscopical characteristics indicate that both of these two species belong to Amanita section Amanita, but differ from other currently known species. Amanita kalasinensis is characterized by having a greyish yellow pileus covering with a conical to granuliform, yellowish white volval remnant; the presence of clamps; and a broadly ellipsoid to ellipsoid basidiospore. Amanita ravicrocina is characterized by having a brown to greyish orange pileus covering with a patchy, white volval remnant; a collar-like volval remnant on the stipe; and a subglobose to broadly ellipsoid basidiospore. Multi-gene phylogenetic analysis of partial nuclear rDNA internal transcribed spacer region (ITS), partial nuclear rDNA large subunit region (nrLSU), RNA polymerase II second largest subunit (RPB2), partial translation elongation factor 1-alpha (TEF1-α), and beta-tubulin gene (TUB) also revealed that positions of A. kalasinensis and A. ravicrocina are well-supported within A. section Amanita, but form distinct lineages and do not show any close relationship with any species. The detailed morphological features, line-drawing illustration, and comparison with morphological similar taxa are provided.