Fungal species are not immune to the threats facing animals and plants and are thus also prone to extinction. Yet, until 2015, fungi were nearly absent on the IUCN Red List. Recent efforts to identify fungal species under threat have significantly increased the number of published fungal assessments. The 597 species of fungi published in the 2022-1 IUCN Red List update (21 July 2022) are the basis for the first global review of the extinction risk of fungi and the threats they face. Nearly 50% of the assessed species are threatened, with 10% NT and 9% DD. For regions with a larger number of assessments (i.e., Europe, North America, and South America), subanalyses are provided. Data for lichenized and nonlichenized fungi are also summarized separately. Habitat loss/degradation followed by climate change, invasive species, and pollution are the primary identified threats. Bias in the data is discussed along with knowledge gaps. Suggested actions to address these gaps are provided along with a discussion of the use of assessments to facilitate on-the-ground conservation efforts. A research agenda for conservation mycology to assist in the assessment process and implementation of effective species/habitat management is presented.

This study presents a comprehensive phylogenetic analysis of the genus Meripilus and its allied genera Henningsia and Physisporinus within the Meripilaceae family, in the broader context of the residual polyporoid clade. The three genera are morphologically similar and characterized by resupinate to pileate basidiomes that harden and often darken upon drying, a monomitic hyphal structure, simple-septate generative hyphae, and globose to ovoid basidiospores, with variable presence of cystidia. Species in Henningsia and Meripilus, in turn, present gloeopleurous hyphae in the context and large, multipileate basidiomes. Recent studies have indicated that Physisporinus, as currently defined, is not monophyletic, with Meripilus nested within it. Phylogenetic analysis based on four molecular markers confirmed the paraphyletic nature of Physisporinus, with Meripilus and Henningsia both nested within it. Morphological examinations of specimens collected in South America, along with revisions of type specimens, show that this segregation is not natural and causes nomenclatural problems. We propose to transfer all species currently placed in Physisporinus into Meripilus, thereby preventing the division of the genus into morphologically indistinguishable groups. As a result of this reclassification, we propose 35 new combinations in Meripilus and describe three new species from South America.

The family Steccherinaceae includes genera with smooth, hydnoid, and poroid hymenophores, monomitic to dimitic hyphal systems, and generative hyphae with clamps or simple septa. Steccherinum is the largest genus in the family, with a worldwide distribution, and is characterized mainly by a dimitic hyphal system and presence of thick-walled encrusted cystidia. Species traditionally included in Steccherinum, however, have been transferred to other genera based on results of molecular phylogenetic analyses. Even though knowledge of Steccherinaceae has increased in the past few years, very little is known about the hydnoid species of the family, especially from the Neotropics. In this study, we present morphological and phylogenetic analyses on hydnoid specimens of Steccherinaceae collected in the Neotropics. Molecular data of nuc internal transcribed spacer region ITS1-5.8S-ITS rDNA (ITS) and portions of nuc 28S rDNA (28S), translation elongation factor 1-α (tef1), and the largest subunit of RNA polymerase II (rpb1) were obtained from Brazilian collections. Types and original collections were studied for morphological comparison. Samples we studied grouped in four different genera of Steccherinaceae: Cabalodontia, Etheirodon, Metuloidea, and Steccherinum. Three new neotropical species, Cabalodontia delicata, Etheirodon purpureum, and Steccherinum larssonii, are described. In addition, the new combinations Cabalodontia albofibrillosa and Metuloidea reniformis are proposed. The four genera presented in this study are compared and discussed in detail.

Phlebiodontia is proposed as a new genus in the Meruliaceae based on morphological and molecular data. The genus is typified by Phlebiodontia rajchenbergii, a new species proposed for Brazil, and also includes P. acanthocystis (Hawaii) and P. subochracea (Germany), which are new combinations proposed in this study. The species of Phlebiodontia are morphologically characterized by yellowish ceraceous basidiomes, with slightly warted to hydnoid hymenophore, monomitic hyphal system, clamped generative hyphae, presence of smooth thin-walled cystidia and broadly ellipsoid to allantoid basidiospores. The phylogenetic relationships of Phlebiodontia and the related taxa in Meruliaceae were inferred from a 4-locus dataset including nuc rDNA ITS1-5.8S-ITS2 (ITS), the D1-D2 domains of 28S rDNA (28S), RNA polymerase II largest subunit (rpb1) and translation elongation factor 1- (tef1). This work presents complete descriptions, comments and discussion about morphology and distribution of Phlebiodontia species.