Leccinum is one of the most important groups of boletes. Most species in this genus are ectomycorrhizal symbionts of various plants, and some of them are well-known edible mushrooms, making it an exceptionally important group ecologically and economically. The scientific problems related to this genus include that the identification of species in this genus from China need to be verified, especially those referring to European or North American species, and knowledge of the phylogeny and diversity of the species from China is limited. In this study, we conducted multi-locus (nrLSU, tef1-α, rpb2) and single-locus (ITS) phylogenetic investigations and morphological observisions of Leccinum from China, Europe and North America. Nine Leccinum species from China, including three new species, namely L. album, L.parascabrum and L.pseudoborneense, were revealed and described. Leccinum album is morphologically characterized by the white basidioma, the white hymenophore staining indistinct greenish blue when injured, and the white context not changing color in pileus but staining distinct greenish blue in the base of the stipe when injured. Leccinumparascabrum is characterized by the initially reddish brown to chestnut-brown and then pale brownish to brown pileus, the white to pallid and then light brown hymenophore lacking color change when injured, and the white context lacking color change in pileus but staining greenish blue in the base of the stipe when injured. Leccinumpseudoborneense is characterized by the pale brown to dark brown pileus, the initially white and then brown hymenophore lacking color change when injured, and the white context in pileus and stipe lacking color change in pileus but staining blue in stipe when bruised. Color photos of fresh basidiomata, line drawings of microscopic features and detailed descriptions of the new species are presented.

The Qinghai-Xizang Plateau (abbreviated as Q-X Plateau) is the world’s highest plateau, characterized by a Holarctic flora. The plateau and its surrounding mountainous areas cover two of the 34 world’s biodiversity hotspots. Former studies have shown that the diversity of fungal species on the plateau, especially that in the east-southeastern part, is remarkably high. In 2017, the Chinese government initiated the second scientific expedition to the Q-X Plateau. Supported by this comprehensive project, we conducted intensive fungal sampling on the Q-X Plateau and its surrounding areas, including the middle and southern parts of the Gaoligong Mountains, the Ailao Mountains, and the Yunnan-Guizhou Plateau. Ninety-two new and notable species of Basidiomycota are reported in this paper, based on 501 specimens and 1706 newly generated DNA sequences. These taxa involve 37 genera of seven orders, i.e., Agaricales, Auriculariales, Boletales, Cantharellales, Phallales, Polyporales, and Russulales, covering both Heterobasidiomycetes and Homobasidiomycetes. One new section, 64 new species, one new subspecies, two new varieties, one new combination, five new synonyms, and 11 new records to China, were documented. Ectomycorrhizal fungi account for two-thirds of the species, while the remaining ones are saprotrophic. Most specimens studied are from altitudes 2000–3700 m, in broad-leaved fagaceous forests, mixed forests with pines and fagaceous trees, and subalpine coniferous forests. Among the 92 species documented, 30 species are exclusive to the subalpine region, and 12 species cover both the subalpine and subtropical zones. Most of these subalpine species are either formerly described temperate species or close relatives of north temperate taxa, which suggests a strong temperate affinity of the funga on the Q-X Plateau. In obvious contrast to the subalpine elements, species from the adjacent subtropical zone often sit on long branches with an isolated position or have a close relationship with species from other subtropical and tropical parts of the world. In the surrounding areas with lower altitude of the Q-X Plateau, the endemic species apparently have evolved for a longer time, some relict species found their refuge, and the funga received more immigrants from the tropics. By comparing the species reported from the western Himalayas, through the Hengduan Mountains and central China to Taiwan Island, we found that altitude matters more than geographical distance in the development of the funga. The sharp altitude gradient on the Q-X Plateau and its surrounding mountains acts as a biodiversity hotspot to further test such speculation. In future studies, more efforts should be focused on other representative groups (Gomphalales, Hymenochaetales, Thelephorales, and Tremellales) and on the southern slope of the western Himalayas and the Pamir-Kunlun regions.

The genus Hemileccinum belongs to the subfamily Xerocomoideae of the family Boletaceae. In this study, phylogenetic inferences of Hemileccinum based on sequences of a single-locus (ITS) and a multi-locus (nrLSU, tef1-α, rpb1, rpb2) were conducted. Four new species, namely H. abidum, H. brevisporum, H. ferrugineipes and H. parvum were delimited and proposed based on morphological and molecular evidence. Descriptions and line-drawings of them were presented, as well as their comparisons to allied taxa. Our study shed new light on the recognition of the genus. The pileipellis of the species in this genus should mostly be regarded as (sub)epithelium to hyphoepithelium, because the pileipellis of most studied species here is composed of short inflated cells in the inner layer (subpellis) and filamentous hyphae in outer layer (suprapellis). The basidiospores of the studied species, including the type species, H. impolitum, have a warty surface.

A new species, Phlegmacium ochraceosquamosum, is described from southwestern China based on morphological and molecular evidence. The new taxon is associated with subtropical fagaceous trees and is characterized by a combination of viscid pale yellow to ochraceous yellow pileus covered with ochraceous brown squamules and fibrils, cylindrical to clavate stipe with ochraceous brown fibrillose girdles, and elongate to subamygdaliform basidiospores. Four species, namely P. glaucopus, P. paracephalixum, P. patrickense, and P. violaceorubens, were first discovered in China. Additional vouchers for two species, namely P. caesiocolor and P. kytoevuorii very recently reported from China, were provided. Illustrated morphological descriptions and comparisons with closely related species are provided. The recognition of these species was further confirmed by phylogenetic analysis based on ITS sequences.

We conducted morphological and molecular analyses to describe a new species of Piperaceae, Piper semi-transparens, which was observed in Hainan, Guangdong and Guangxi Provinces, China. Detailed morphological comparisons between the newly discovered species and other members of Piper indicate that Piper semi-transparens is similar to P. bonii and P. bonii var. macrophyllum, from which it differs in having glabrous leaf blades; stem densely short and unbranched pubescent when young, glabrous when mature; veins 5(–7); stamens 2; stigmas 3, rarely 4; spikes color white when mature; floral bracts glabrous; pericarp white and semi-transparent. Molecular analyses based on the ITS marker of nuclear ribosomal DNA strongly support that P. semi-transparens is a new species in the genus Piper, most closely related to P. bonii and P. bonii var. macrophyllum.