Amanita chuformis, a new Amanita species with a marginate basal bulb

Amanita chuformis, a new species in the A. pseudogemmata-A. ballerina subclade of Amanita section Phalloideae, is described from China with both multi-gene phylogenetic and morphological data. This species occurs in subalpine coniferous forests in southwestern China and is characterized by its brownish pileus decorated with conical to patch-like volval remnants, a slightly striate pileal margin, a marginate basal bulb, and weakly amyloid to amyloid, subglobose to broadly ellipsoid basidiospores measuring 9.5–11 × 8–9.5 μm. Phylogenetic analyses based on internal transcribed spacer (ITS) region, the nuclear ribosomal RNA large subunit (nrLSU) and the genes for the polymerase II second largest subunit (RPB2) and for translation elongation factor 1-α (TEF1α) indicate A. chuformis is close to A. pseudogemmata and A. levistriata. The new species is described, illustrated and compared with closely related and similar species.