Powdery mildew is an economically important disease caused by c.1000 different fungal species. Erysiphe vaccinii is an emerging powdery mildew species that is impacting the blueberry industry. Once confined to North America, E.vaccinii is now spreading rapidly across major blueberry-growing regions, including China, Morocco, Mexico, and the USA, threatening millions in losses. This study documents its recent global spread by analyzing both herbarium specimens, some over 150-yr-old, and fresh samples collected world-wide. Our findings were integrated into a 'living phylogeny' via T-BAS to simplify pathogen identification and enable rapid responses to new outbreaks. We identified 50 haplotypes, two primary introductions world-wide, and revealed a shift from a generalist to a specialist pathogen. This research provides insights into the complexities of host specialization and highlights the need to address this emerging global threat to blueberry production.

Powdery mildews are highly destructive fungal plant pathogens that have a significant economic impact on both agricultural and ecological systems worldwide. The intricate relationship between powdery mildews and their host plants has led to cospeciation. In this study, we conducted an extensive evaluation of powdery mildew hosts to provide an updated understanding of the host ranges and distributions of these fungi. The "United States National Fungus Collections Fungus-Host Dataset" is the primary source of information for our analyses. The analysis of the dataset demonstrated the worldwide prevalence of powdery mildews; the data contained over 72,000 reports of powdery mildews, representing ∼8.7% of all host-fungal records. We have updated the taxonomy and nomenclature of powdery mildews. In total, powdery mildews infect ∼10,125 host taxa belonging to 205 families of flowering plants, which accounts for 1,970 genera in 200 countries across six continents. Furthermore, we estimate that powdery mildews infect approximately 2.9% of described angiosperm species. Our study underscores the need for regular updates on powdery mildew host information due to the continuously evolving taxonomy and the discovery of new host taxa. Since 1986, we estimate an additional 1,866 host taxa, 353 genera, and 36 families have been reported. Additionally, the identification of powdery mildew hosts provides valuable insights into the coevolutionary dynamics between the fungi and their plant hosts. Overall, this updated list provides valuable insights into the taxonomy and geographic distribution of powdery mildew species, which builds upon the previous work of Amano in 1986. Discerning the geographic spread and host range of economically significant plant pathogens is vital for biosecurity measures and identifying the origins and expansion of potentially harmful pathogens.

Although it is well documented that mountains tend to exhibit high biodiversity, how geological processes affect the assemblage of montane floras is a matter of ongoing research. Here, we explore landform-specific differences among montane floras based on a dataset comprising 17,576 angiosperm species representing 140 Chinese mountain floras, which we define as the collection of all angiosperm species growing on a specific mountain. Our results show that igneous bedrock (granitic and karst-granitic landforms) is correlated with higher species richness and phylogenetic overdispersion, while the opposite is true for sedimentary bedrock (karst, Danxia, and desert landforms), which is correlated with phylogenetic clustering. Furthermore, we show that landform type was the primary determinant of the assembly of evolutionarily older species within floras, while climate was a greater determinant for younger species. Our study indicates that landform type not only affects montane species richness, but also contributes to the composition of montane floras. To explain the assembly and differentiation of mountain floras, we propose the 'floristic geo-lithology hypothesis', which highlights the role of bedrock and landform processes in montane floristic assembly and provides insights for future research on speciation, migration, and biodiversity in montane regions.

Rubus L. (Rosaceae, Rosoideae) contains around 700 species distributed on all continents except Antarctica, with the highest species diversity in temperate to subtropical regions of the northern hemisphere. The taxonomy of Rubus is challenging due to the frequency of polyploidy, hybridization and apomixis. Previous studies mostly sampled sparsely and used limited DNA sequence data. The evolutionary relationships between infrageneric taxa, therefore, remain to be further clarified. In the present study, genotyping by sequencing (GBS) reduced-representation genome sequencing data from 186 accessions representing 65 species, 1 subspecies and 17 varieties of Rubus, with emphasis on diploid species, were used to infer a phylogeny using maximum likelihood and maximum parsimony methods. The major results were as follows: (1) we confirmed or reconfirmed the polyphyly or paraphyly of some traditionally circumscribed subgenera, sections and subsections; (2) 19 well-supported clades, which differed from one another on molecular, morphological and geographical grounds, were identified for the species sampled; (3) characteristics such as plants with dense bristles or not, leaves leathery or papyraceous, number of carpels, instead of inflorescences paniculate or not, aggregate fruits and leaves abaxially tomentose or not, may be of some use in classifying taxa whose drupelets are united into a thimble-shaped aggregate fruit that falls in its entirety from the dry receptacle; and (4) a preliminary classification scheme of diploid species of Rubus is proposed based on our results combined with those from previous phylogenetic analyses.

Although gymnosperms are well known for their large size, being the largest, tallest and most massive living organisms on earth, an exceptionally diminutive gymnosperm, Ephedra monosperma Gmelin ex C. A. Meyer (Ephedraceae), from southwestern China is compared with the much more massive gymnosperms that tend to receive far greater attention and publicity. Photographs of E. monosperma and its natural habitat are provided and voucher specimens are cited.

Genomic studies are now poised to explore whole communities of species. The -70 species of woody plants that anchor the coastal ecosystems of the tropics, collectively referred to as mangroves, are particularly suited to this exploration. In this study, we de novo sequenced the whole genomes of 32 mangroves, which we combined with other sequences of 30 additional species, comprising almost all mangroves globally. These community-wide genomic data will be valuable for ecology, evolution and biodiversity research. While the data revealed 27 independent origins of mangroves, the total phylogeny shows only modest increases in species number, even in coastal areas of active speciation, suggesting that mangrove extinction is common. A possible explanation for common extinction is the frequent sea-level rises and falls (SLRs and SLFs) documented in the geological record. Indeed, near-extinctions of species with extremely small population size (N) often happened during periods of rapid SLR, as revealed by the genome-wide heterozygosity of almost all mangroves. Reduction in N has possibly been further compounded by population fragmentation and the subsequent accumulation of deleterious mutations, thus pushing mangroves even closer to extinction. Crucially, the impact of the next SLR will be exacerbated by human encroachment into these mangrove habitats, potentially altering the ecosystems of tropical coasts irreversibly.

Bougainvillea Comm. ex Juss. is one of the renowned genera in the Nyctaginaceae, but despite its recognized horticultural value, the taxonomy and phylogeny of the genus is not well-studied. Phylogenetic reconstructions based on plastid genomes showed that B. pachyphylla and B. peruviana are basal taxa, while B. spinosa is sister to two distinct clades: the predominantly cultivated Bougainvillea clade (B. spectabilis, B. glabra, B. arborea, B. cultivar, B. praecox) and the clade containing wild species of Bougainvillea (B. berberidifolia, B. campanulata, B. infesta, B. modesta, B. luteoalba, B. stipitata, and B. stipitata var. grisebachiana). Early divergence of B. peruviana, B. pachyphylla and B. spinosa is highly supported, thus the previously proposed division of Bougainvillea into two subgenera (Bougainvillea and Tricycla) was not reflected in this study. Morphological analysis also revealed that leaf arrangement, size, and indumentum together with the perianth tube and anthocarp shape and indumentum are important characteristics in differentiating the species of Bougainvillea. In the present study, 11 species and one variety are recognized in Bougainvillea. Six names are newly reduced to synonymy, and lectotypes are designated for 27 names. In addition, a revised identification key and illustrations of the distinguishing parts are also provided in the paper.

Paraphlomisjinggangshanensis (Lamiaceae), a new species from Jiangxi Province, China, is described and illustrated. The new species is morphologically similar to P.intermedia, but can be easily distinguished from the latter by its cordate leaf base (vs. cuneate, decurrent), stem and calyx tube with glandular hairs (vs. short pubescent), and glabrous anthers (vs. ciliate anthers). A phylogenetic analysis, based on ITS regions, suggests that P.jinggangshanensis represents a separate branch in Paraphlomis and is closely related to Clade II. It is currently known only from Jinggangshan National Natural Reserve. Because of its limited distribution and small population size, the species was assessed as Near Threatened (NT) according to the IUCN Red List Categories and Criteria.

Geographical names and the entities they represent act as a fundamental cornerstone across numerous disciplines. However, inconsistent geographical names and arbitrarily defined regional geographical scales are common, hindering cross-disciplinary communication and synthesis. The Pan-Tibetan Highlands, comprising the Tibetan Plateau, Himalaya, Hengduan Mountains and Mountains of Central Asia, is a case in point. To rectify these inconsistencies of terminology, we employed a multi-disciplinary approach to standardize the nomenclature of the Tibetan Plateau and the three adjacent mountain regions, defining their spatial extent using historical and contemporary perspectives. A literature meta-analysis indicated that 'Tibetan Plateau', 'Himalaya' and 'Hengduan Mountains' are the most suitable names for these regions in terms of both priority (earliest use) and popularity, whereas 'Mountains of Central Asia' emerges as appropriate for the mountain chains to the west of the Tibetan Plateau. The new term 'Pan-Tibetan Highlands' is proposed to replace the less precise and arguably misleading 'High Mountain Asia' for these regions collectively. Additionally, new geographical boundaries, applicable back through time, are proposed for each region, based on geological and geomorphological features. Using these new boundaries, the Pan-Tibetan Highlands area is 3.95 x 10(6) km(2) with a mean elevation of 3824 m, while the Tibetan Plateau is smaller (1.82 x 10(6) km(2)) and higher (4465 m) than commonly assumed. Across the Pan-Tibetan Highlands, the proportion of protected areas is far below the proposed 30% anticipated in the post-2020 Global Biodiversity Framework target with only a few exceptions. Additionally, the Hengduan Mountains showed the highest vascular plant species richness and endemism, followed by Himalaya, Mountains of Central Asia and the Tibetan Plateau. The obvious conservation gap in the Pan-Tibetan Highlands calls for urgent research-based optimization of conservation networks. Our approach benefits quantitative spatial analysis by providing well-defined geographical scales for various fields, aiding cross-disciplinary comparisons and synthesis.

In 1958, Chun and Kuang described Cathaya Chun & Kuang as a new genus of Pinaceae. They included one fossil species, C.loehri (Engelh. & Kink.) Chun & Kuang and two extant species, C.argyrophylla Chun & Kuang and C.nanchuanensis Chun & Kuang. Under Art. 40.1 of the Shenzhen Code, they did not validly publish Cathaya because they did not designate a type species for the generic name. Four years later (Chun and Kuang 1962), they again published on Cathaya (in Chinese) where they cited the 1958 publication and included one species C.argyrophylla (with C.nanchuanensis in synonymy) under Cathaya. According to Art. 40.3, they validated both the generic name Cathaya and C.argyrophylla in 1962. Further examination of the type collection and botanical history of the discovery of C.argyrophylla revealed that the type collection Guang-Fu-Lin-Qu Exped. 00198 consists of 11 duplicates in the South China Institute of Botany (IBSC) and 9 duplicates in other herbaria (GAC, IBK, PE, SZ) and that the intended type specimen (IBSC0000004) consists of two gatherings: the bark, reproductive shoot and seed cones collected in 1955, whereas pollen-bearing cones were collected in 1956. We thus lectotypify the name C.argyrophylla with the specimen Guang-Fu-Lin-Qu Exped. 00198 (IBSC0000004 excl. pollen-bearing cones).

The type collection of Phoebe puwenensis consists of 18 specimens in the herbarium of Nanjing Forestry University (NF). Of those specimens, W. C. Cheng 30001 (NF2004054), which bears the notation “sp. nov.” and also a handwritten diagnosis, is chosen as the lectotype.

(2813) Hedyotis diffusa Willd., Sp. Pl. 1: 566. Jul 1798, nom. cons. prop. Typus: “Oldenlandia capensis?”, Klein (B-W barcode B -W 02588 -01 0, right-hand specimen [“B”]), typ. cons. prop. The name Hedyotis diffusa Willd. (Sp. Pl. 1: 566. 1798) has been applied for nearly two centuries to a taxon with usually solitary white flowers (Smith in Rees, Cycl. 17: Hedyotis no. 14. 1811). More recently, the species has been treated as Scleromitrion diffusum (Willd.) R.J. Wang (Wang & al. in Trop. Subtrop. Bot. 22: 440. 2014) based on a taxon with solitary-flowered (or 2- or 3-flowered) inflorescences. Conservation is required to preserve this longstanding application of the name. When Willdenow (l.c.) described Hedyotis diffusa as “Flores axillares solitarii pedunculati”, he did not specify in the protologue whether “pedunculati” referred to the peduncle of a solitary flower or an inflorescence. His description was interpreted as referring to a solitary flower by subsequent authors, including Smith (l.c.) as “Flower axillary, solitary, stalked”. Roxburgh (Hort. Bengal.: 11. 1814) initially transferred H. diffusa to Oldenlandia, as O. diffusa, without comment or description, but later (Fl. Ind. 1: 444. 1820) described the species as “Peduncles axillary, solitary, one-flowered […].” Hooker (Fl. Brit. India 3: 65. 1880), circumscribing the species in a broader sense, published two varieties of O. diffusa, including O. diffusa var. extensa Hook. f., which he described as 1- or 2-flowered and with a longer peduncle. This application of the name H. diffusa to a solitary-flowered taxon gained widespread acceptance around the world (Makino, New Ill. Fl. Japan: 580. 1961; Chao in Li & al., Fl. Taiwan 4: 271–272. 1978; Lee, Ill. Fl. Korea: 693. 1979; Manilal & Sivarajan, Fl. Calicut: 139–141. 1982). The 1- or 2-flowered concept of Hedyotis/Oldenlandia diffusa was followed until Sivarajan & Biju (in Taxon 39: 665–674. 1990) chose as lectotype, against the traditional application, Willdenow Herbarium no. 2588-01 A (material on left-hand side of sheet), which is a specimen of Hedyotis pseudocorymbosa Bakh. f. (Bakhuizen van den Brink & Koster in Blumea 12: 62. 1963) with a cymose inflorescence. Consequently, Oldenlandia diffusa (Willd.) Roxb. in the sense of Roxburgh, including Willdenow Herbarium no. 2588-01 B, was treated as Hedyotis brachypoda (DC.) Sivar. & Biju, based on Oldenlandia brachypoda DC. (Prodr. 4: 424. 1830). Hedyotis pseudocorymbosa was reduced to the synonymy of H. diffusa. Sivarajan & Biju's (l.c.) lectotypification was based on the interpretation that “pe-dunculati” in the protologue should refer to a multiple-flowered, stalked inflorescence. They mentioned that Roxburgh “started the confusion by […] misreading […] ‘solitarii pedunculati’ […] as 1-flowered” and pointed out that the flowers of Willdenow Herbarium 2588-01 B are sessile. Therefore, going against traditional usage, they lectotypified the name with a taxon with a (1-) 3- to 7-flowered pedunculate cyme. However, in the description of other species in Willdenow's Species plantarum, the word “pedunculati” was applied to both the stalk of a solitary flower, which is reflected in the description of Convolvulus pes-caprae L. as “pedunculis unifloris” (Willdenow, l.c.: 876), and also to multi-flowered inflorescences as “pedunculis multifloris” in Convolvulus vitifolius Burm. f. (Willdenow, l.c.: 864). The lectotypification by Sivarajan & Biju based on their interpretation of “pedunculati” was therefore not well grounded. Later, Dutta & Deb (Taxon. Revis. Hedyotis: 143–147. 2004) cited Willdenow Herbarium no. 2588-01 B with solitary flowers as the type of Hedyotis diffusa, describing the species as having “solitary sessile or pedicelled flower or pedunculate cyme of 2–3 flowers”. However, it was not an effective lectotypification because the phrase “designated here” or an equivalent was not included (Art. 7.11 of the ICN; Turland & al. in Regnum Veg. 159. 2018). The treatment also lacked priority over Sivarajan & Biju under Art. 9.19 of the ICN. In 2014, Wang & al. (l.c.) transferred Hedyotis diffusa in the sense of Dutta & Deb (l.c.), not of Sivarajan & Biju (l.c.), to Scleromitrion as S. diffusum. The treatment was based on the latest delimitation of the Scleromitrion clade, which was characterized by having homostylous flowers and exserted stamens and style (Guo & al. in Molec. Phylogen. Evol. 67: 110–122. 2013; Neupane & al. in Taxon 64: 299–322. 2015). The combination was applied to a solitary-flowered (or rarely 2- or 3-flowered) taxon. Although the combination is legitimate, the treatment is problematic due to misapplication of the name, which must be applied to a (1-) 3- to 7-flowered species according to the existing lectotype of the basionym. Despite Sivarajan & Biju's (l.c.) lectotypification, the traditional concept of Hedyotis diffusa is still widely adopted in the literature, in taxonomic revisions (Dutta & Deb, l.c.), regional floras (Lo & al. in Lo, Fl. Reipubl. Popularis Sin. 71(1): 26–77. 1999; Chen & Taylor in Wu & Raven, Fl. China 19: 147–174. 2011), traditional Chinese medicine (Chang & But, Pharmacol. Applic. Chin. Mater. Med. 1: 395–403. 1986; Li & al. in Food Chem. 119: 1239–1245. 2010; Zhao & Xiao, Encycl. Med. Pl. 4: 342–347. 2010), and anti-cancer research (Lee & al. in Amer. J. Chin. Med. 39: 201–213. 2011; Chen & al. in Molecules 21: 710. 2016). Chen & al. (l.c.) clearly defined the species with which they were dealing in a review of the phytochemistry, pharmacology, quality control, and pharmacokinetic characteristics of H. diffusa for clinical use based on the treatment in the Flora of China. To avoid further confusion, we propose to conserve the type indicated by Dutta & Deb (l.c.), Willdenow Herbarium no. 2588-01 B (material on right-hand side) (image available at https://herbarium.bgbm.org/object/BW02588010), representing a 1-flowered taxon, as a conserved type. This would preserve over 200 years of traditional and current usage. The species is, in a broad sense, a 1- to 3-flowered taxon, including in the sense of Smith (l.c.), Roxburgh (l.c. 1820), Dutta & Deb (l.c.), and Wang (l.c.). Conservation of Hedyotis diffusa with B-W no. 2588-01 B as type will affect the application of two names: Scleromitrion brachypodum (DC.) T.C. Hsu (Hsu & Chen in Taiwania 62: 151–156. 2017) (O. brachypoda DC.) will become a synonym of S. diffusum. Oldenlandia pseudocorymbosa (Bakh. f.) Raizada (Suppl. Fl. Gangetic Plain: 95. 1976) will apply to a distinct species, which matches its existing application (Dutta & Deb, l.c.; Nandikar & Kishor in Blumea 64: 225–230. 2019), instead of being included in synonymy under Hedyotis diffusa. Willdenow Herbarium no. 2588 includes two sheets of three individuals from three different taxa. Specimen B-W no. 2588-01 A will be Oldenlandia pseudocorymbosa and B-W no. 2588-02 is O. corymbosa L. (Sp. Pl.: 119. 1753). As the treatment by Sivarajan & Biju has not been adopted by other taxonomists, the conservation would not have a significant impact on the current application of the two names. The conservation will contribute to nomenclatural stability and prevent confusion in the widespread application of the name Hedyotis diffusa in traditional Chinese medicine and anti-cancer research. If the proposal is rejected, the name of the taxon currently known as H. diffusa would need to be changed to Scleromitrion brachypodum, as the name H. diffusa would have to be applied to a different taxon currently accepted as Oldenlandia pseudocorymbosa. TYS, https://orcid.org/0000-0001-5725-3314 MHYY, https://orcid.org/0000-0001-5029-819X DEB, https://orcid.org/0000-0003-1483-9651 PCS, https://orcid.org/0000-0001-6848-5073 DTWL, https://orcid.org/0000-0002-3443-1808 The authors would like to thank Prof. John McNeill and Dr. John Wiersema for the review of this manuscript. The project is funded by Wu Jieh Yee Charitable Foundation Limited. The authors would like to thank Harvard Herbaria staff for their technical support and hospitality during specimen check for this project. The first author would also like to thank Mr. Ying Wai Lam for his guidance on nomenclatural studies.

Identifying the contours and correlates of species turnover is central to understanding the nature of biogeographical regions. The Hengduan Mountains region of south-central China (HMR) is well known for its high diversity of plants, but its boundaries and internal floristic structure are poorly understood, especially in relation to geographical and environmental factors. With data on occurrences and elevational ranges of seed plants across the HMR and adjacent areas of the greater Qinghai-Tibet Plateau, we identified motifs (distinct species assemblages) by Grade of Membership models, and characterized relative contributions of geography, elevation, and climate to their spatial patterns. Motifs segregate primarily by latitude, elevation, and correlated environmental variables, most sharply across the tropical-temperate divide. Secondarily, they segregate by longitude and geographical features, and reveal a novel divide across the Jinsha River. A core set of motifs corresponds to previous delineations of the HMR. The HMR biodiversity hotspot is more a mosaic of floristic elements than a cohesive entity. Grade of Membership models effectively reveal the geographical contours of biotic structure, and are a valuable new tool for biogeographical analysis.

Sequencing multiple species that share the same ecological niche may be a new frontier for genomic studies. While such studies should shed light on molecular convergence, genomic-level analyses have been unsuccessful, due mainly to the absence of empirical controls. Woody plant species that colonized the global tropical coasts, collectively referred to as mangroves, are ideal for convergence studies. Here, we sequenced the genomes/transcriptomes of 16 species belonging in three major mangrove clades. To detect convergence in a large phylogeny, a CCS+ model is implemented, extending the more limited CCS method (convergence at conservative sites). Using the empirical control for reference, the CCS+ model reduces the noises drastically, thus permitting the identification of 73 convergent genes with P-true (probability of true convergence) > 0.9. Products of the convergent genes tend to be on the plasma membrane associated with salinity tolerance. Importantly, convergence is more often manifested at a higher level than at amino-acid (AA) sites. Relative to >50 plant species, mangroves strongly prefer 4 AAs and avoid 5 others across the genome. AA substitutions between mangrove species strongly reflect these tendencies. In conclusion, the selection of taxa, the number of species and, in particular, the empirical control are all crucial for detecting genome-wide convergence. We believe this large study of mangroves is the first successful attempt at detecting genome-wide site convergence.

In China,three institutes for botanical research were established in the 1920s,namely the Department of Botany,Biological Laboratory of the Science Society of China (1922,Nanjing),the Fan Memorial Institute of Biology (1928,Peiping),and the Institute of Botany,Peiping Academy of Sciences (1929,Peiping).Since then,plant taxonomy,plant systematics,and phytogeography have advanced and prospered as scientific disciplines in China.

From 2000 to 2019, 11,895 new names or new additions to the Chinese vascular flora were proposed by 4226 individuals (4086 articles and 140 books), as documented in the Chinese Plant Names Index (CPNI). During those 20 years, 4407 new taxa of vascular plants were described from China, including 7 new families, 132 new genera, 3543 new species, 68 new subspecies, 497 new varieties and 160 new forms. Additionally, 3562 new combinations and names at new rank and 306 new replacement names were also proposed. Among these various new names were 150 invalid names and 108 illegitimate names, including some that have not been resolved. Six hundred and forty three vascular plants were reported as new to China, while 2349 names were reduced to synonyms of 1406 taxa. The data show that the Chinese flora increased in size at the rate of about 200 taxa annually during those years. Despite the increased attention given to biodiversity in recent years, the evidence indicates that a large number of species in China have yet to be discovered. Further basic investigation of the Chinese flora is needed. Additionally, in the past two decades only 8.5％ of the newly published species have been based on molecular evidence, but in the past five years such data have increased significantly, reaching about 20％. Molecular data will undoubtedly become increasingly significant in the discovery of new species in the coming years. Yunnan, Guangxi, Sichuan, Xizang and Taiwan were important sources of new discoveries, with more than 3300 new taxa and records from these five provinces. By area, Taiwan and Hainan, two islands in southern China, have the highest density of newly discovered species. Regional plant surveys are still needed, especially in areas in the southwest and on the southern islands.