An accurate identification of poisonous mushrooms and the confirmation of the toxins involved are both of great importance in the treatment of mushroom poisoning incidents. In recent years, cases of mushroom poisoning by Inosperma spp. have been repeatedly reported from tropical Asia. It is urgent to know the real species diversity of Inosperma in this region. In the present study, we proposed two new Inosperma species from tropical Asia, namely I. muscarium and I. hainanense. They were described based on morphology and multilocus phylogeny. Detailed descriptions, color photographs and the discussion with other closely related species of the two new taxa were provided. In addition, a comprehensive muscarine determination of these two new species using ultrahigh performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) approach has been performed. Results showed that these two species were muscarine positive, with a content of 16.03 ± 1.23 g/kg in I. muscarium and a content of 11.87 ± 3.02 g/kg in I. hainanense, much higher than the known species I. virosum. Recovery of muscarine ranged from 93.45% to 97.25%, and the average recovery is 95.56%.

Pseudosperma citrinostipes sp. nov. from southwestern China is described and illustrated based on morphological, ecological, and molecular data. The new species is characterized by a medium-sized slender habit, straw yellow to golden yellow pileus, crowded lamellae without olive tinges, an equal stipe with lemon yellow to golden fibrils, large ellipsoid to subphaseoliform basidiospores, subfusiform to lageniform cheilocystidia, and the presence of caulocystidia at the stipe apex. Phylogenetically, P. citrinostipes is placed in the P. rimosum complex and is sister to the rest of the taxa of the species complex.

Many species of Inosperma cause neurotoxic poisoning in humans after consumption around the world. However, the toxic species of Inosperma and its toxin content remain unclear. In the present study, we proposed five new Inosperma species from China, namely, I. longisporum, I. nivalellum, I. sphaerobulbosum, I. squamulosobrunneum, and I. squamulosohinnuleum. Morphological and molecular phylogenetic analyses based on three genes (ITS, nrLSU, rpb2) revealed that these taxa are independent species. A key to 17 species of Inosperma in China is provided. In addition, targeted screening for the most notorious mushroom neurotoxins, muscarine, psilocybin, ibotenic acid, and muscimol, in these five new species was performed by using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Our results show that the neurotoxin contents in these five species varied: I. sphaerobulbosum contains none of the tested neurotoxins; I. nivalellum is muscarine positive; I. longisporum and I. squamulosohinnuleum contain both ibotenic acid and muscimol, and I. squamulosobrunneum only contains muscimol; psilocybin was not detected in these five new species.

Globally, many species of Amanita sect. Amanita (Amanitaceae, Agaricales) cause poisoning after consumption. Amanita flavomelleicepssp. nov. and Amanita parvisychnopyramissp. nov., two new species of A. section Amanita from China, are described here. Morphology and molecular phylogenetic analyses based on five genes (ITS, nrLSU, RPB2, TEF1-α, and TUB2) revealed these two taxa as distinct species. Amanita flavomelleicepssp. nov. is characterized by a yellowish-to-yellow pileus covered by verrucose volval remnants; a subglobose basal bulb with shortly limbate; subglobose to broadly ellipsoid, inamyloid basidiospores. Amanita parvisychnopyramissp. nov. is characterized by a brownish pileus covered by subconical volval remnants; an ovate basal bulb with a cream limbate; and subglobose-to-broadly ellipsoid, inamyloid basidiospores. Screening for the most notorious toxins by liquid chromatography tandem mass spectrometry (LC-MS/MS) revealed the presence of ibotenic acid (IBO) and muscimol (MUS) in A. parvisychnopyramis and the absence of these toxins in A. flavomelleiceps.