Invasive species are a subset of naturalized species, and naturalized species are a subset of alien species. Determining the relationship among these three assemblages would be helpful in predicting and preventing biological invasion. Here, we reviewed the families, lifeforms, origins, introduction pathways and phylogenetic diversity of alien, naturalized and invasive vascular plants in China. The results show that species in the Asteraceae, Fabaceae and Poaceae families had a high dominance among alien, naturalized and invasive species. Moreover, almost all alien species in the Amaranthaceae, Solanaceae, Convolvulaceae and Euphorbiaceae families became naturalized species, and about 26.7% of the naturalized species became invasive species. Perennial herbs comprised a higher proportion of alien species than did annual herbs, though annual herbs were more suited to becoming invasive than perennial herbs. A considerable proportion (57.8%) of invasive species were introduced from America. More than half (56.5%) of alien species were introduced for their ornamental value, and half of these have become naturalized in China. Moreover, about half (55.2%) of all invasive species were introduced for their economic value (including ornamental, foraging and medicinal purposes). Invasive species were phylogenetically clustered and phylogenetically distant from alien and naturalized species, which indicates that phylogenetic differences could be helpful in becoming invasive. There is no doubt that human activity plays a significant role in biological invasion. This study suggests that when introducing alien species to a region, decision-makers should certainly consider the species’ phylogeny, beyond just its fundamental characteristics.

Large-diameter trees have mainly been used for timber production in forestry practices. Recently, their critical roles played in biodiversity conservation and maintenance of ecosystem functions have been recognized. However, current forestry policy on the management of large-diameter trees is weak. As China is the biggest consumer of large-diameter timbers, how to maintain sustainable large-diameter timber resources as well as maximize ecological functions of the forests is a critical question to address. Here we summarize historical uses, distribution patterns, and management strategies of large-diameter trees in China. We found that large-diameter trees are mainly distributed in old-growth forests. Although China’s forest cover has increased rapidly in the past decades, large-diameter trees are rarely found in plantation forests and secondary forests. We suggest that knowledge of large-diameter trees should be widely disseminated in local forestry departments, especially their irreplaceable value in terms of biodiversity conservation and ecosystem functions. Protection of large-diameter trees, especially those in old-growth forests, is critical for sustainable forestry. To meet the increasing demand of large-diameter timbers, plantation forests and secondary forests should apply forest density management with thinning to cultivate more large-diameter trees.

Discovery rates of new plant species need to be accelerated because many species will be extinct before they are formally described. Current studies have focused on where new species may occur and their characteristics. However, who will actually discover and describe these new species has received limited attention. Here, we used 31 576 vascular plant species distributed and described in China as a case study to explore the temporal patterns of the nationalities of the taxonomists. We found that most recently described species are endemic species, and there has been an increasing proportion of species descriptions by resident Chinese taxonomists over time. The proportion of species described by resident taxonomists reached an average of 80.8% between 1977 and 2018. By contrast, species discoveries by non-resident experts, often non-endemic species, showed signs of levelling off. Our study underscores an urgent need for training of, support for and collaboration with resident taxonomists in megadiverse countries with a high potential of discovering undescribed plant species.

In this paper, Sedum simingshanensesp. nov. is described as a new species based on morphological and molecular analyses, and its taxonomic relationships are discussed. Morphological analysis indicates S. simingshanense should be classified in the genus Sedum sect. Sedum and is distinct from the related species S. xunvense and S. formosanum in the morphology of its solitary, light green and smooth stems, flattened leaves, larger, obovate and spurless sepals, yellow anthers, 22–30 ovules per carpel, oblique follicles, and its habitat on shaded slopes or rocks. Phylogenetic analysis of sequences of the nuclear ribosomal internal transcribed spacer (ITS) also demonstrates that S. simingshanense has a highest similarity of only 97.22% with any known species and S. formosanum is the closest extant relative of the new species.

In this paper, Sedum yongkangense is described as a new species based on morphological and molecular analyses, and its taxonomic relationships are discussed. Morphological analysis indicates S. yongkangense should be classified in the genus Sedum L. sect. Sedum and is distinct from the related species S. ryukyuense, S. mukojimense and S. boninense in having the morphology of a biennial life form; spreading cymes with numerous flowers; unequal, linear, terete sepals; horizontally spreading follicles; and an inland habitat. Molecular analysis of sequences of the nuclear ribosomal internal transcribed spacer (ITS) also demonstrates that S. yongkangense has a highest similarity of only 87.21% with any known species. Phylogenetic analyses indicate that S. yongkangense should be closely related to S. bulbiferum, but the latter differs in having the morphology of a perennial life form; a congested fertile stem; axillary bulbils of leaves; a spatulate-oblanceolate and flat leaf blade; lanceolate to oblanceolate and flat sepals; and deep yellow anthers and spreading follicles.

In this paper, Nanocnide simingshanensis is described as a new species based on morphological and molecular analyses, and its taxonomic relationships are discussed. The new species is currently known only from the Siming Mountain region of Yuyao County and the Yaolin National Forest Park of Tonglu County, both in Zhejiang Province, eastern China, where it grows in shrubs at an elevation of about 650 m under deciduous broad-leaved forests and at a limestone cave entrance. Morphological analysis strongly supports that N. simingshanensis should be classified into the genus Nanocnide. This species is distinguished from the related species N. pilosa and N. lobata by having long straight hirsute hairs perpendicular to the stem, petioles and peduncles, longer petioles, larger leaf blades, and female inflorescences developing on branchlets. It differs from N. zhejiangensis and N. japonica by having glomerulate male inflorescences shorter than leaves (vs. cymose inflorescences longer than leaves). Nuclear ribosomal DNA internal transcribed spacer (ITS) phylogenetic analysis demonstrates that N. pilosa and N. lobata are the closest extant relatives to the new species.