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Artocarpus altilis (Parkinson ex F.A. Zorn) Fosberg is native to the Pacific Islands, India, and the Philippines. It is also cultivated in Taiwan and Hainan. The complete plastome of the species was assembled and annotated in this study. The circular genome was 160,184 bp in size, presenting a typical quadripartite structure including two inverted repeats (IRs) of 25,734 bp, a large single-copy (LSC) of 88,791 bp, and a small single-copy (SSC) of 19,925 bp. The genome contained 132 genes, including 87 protein-coding genes, 37 tRNA genes, and eight rRNA genes. The total G/C content of complete plastome was 36.0%, with the corresponding values of the LSC, SSC, and IR being 33.7%, 28.8%, and 42.7%, respectively. The complete plastome sequence of A. altilis (Parkinson ex F.A. Zorn) Fosberg will make contributions to the conservation genetics of this species as well as to phylogenetic studies of Moraceae.

Abstract Within urban green spaces, tree species diversity is believed to correlate with aboveground biomass, though there is some disagreement within the literature on the strength and directionality of the relationship. Therefore, we assessed the relationship between the biodiversity of woody species and the aboveground biomass of woody plant species in the tropical, coastal city of Haikou in southern China. To accomplish this, we obtained comprehensive tree and site data through field sampling of 190 urban functional units (UFUs, or work units) corresponding to six types of land uses governmental‐institutional, industrial‐commercial, park‐recreational, residential, transport infrastructure, and undeveloped area. Based on our field data, we investigated the relationship between tree species diversity and aboveground biomass using multiple regression, which revealed significant relationships across all five types of land uses. Aboveground biomass in green spaces was also correlated with anthropogenic factors, especially time since urban development, or site age, annual maintenance frequency by human caretakers, and human population density. Among these factors, maintenance is the strongest predictor of aboveground biomass in urban green space. Therefore, this study highlights the critical role of maintenance of urban green space in promoting both aboveground biomass and woody biodiversity in urban ecosystems and, consequently, on urban ecosystem services. Our findings contribute to a deeper understanding of the ecosystem services provided by communities of woody plant species in urban areas.

Abstract Background Myrtales is a species rich branch of Rosidae, with many species having important economic, medicinal, and ornamental value. At present, although there are reports on the chloroplast structure of Myrtales, a comprehensive analysis of the chloroplast structure of Myrtales is lacking. Phylogenetic and divergence time estimates of Myrtales are mostly constructed by using chloroplast gene fragments, and the support for relationships is low. A more reliable method to reconstruct the species divergence time and phylogenetic relationships is by using whole chloroplast genomes. In this study, we comprehensively analyzed the structural characteristics of Myrtales chloroplasts, compared variation hotspots, and reconstructed the species differentiation time of Myrtales with four fossils and one secondary calibration point. Results A total of 92 chloroplast sequences of Myrtales, representing six families, 16 subfamilies and 78 genera, were obtained including nine newly sequenced chloroplasts by whole genome sequencing. Structural analyses showed that the chloroplasts range in size between 152,214–171,315 bp and exhibit a typical four part structure. The IR region is between 23,901–36,747 bp, with the large single copy region spanning 83,691–91,249 bp and the small single copy region spanning 11,150–19,703 bp. In total, 123–133 genes are present in the chloroplasts including 77–81 protein coding genes, four rRNA genes and 30–31 tRNA genes. The GC content was 36.9–38.9%, with the average GC content being 37%. The GC content in the LSC, SSC and IR regions was 34.7–37.3%, 30.6–36.8% and 39.7–43.5%, respectively. By analyzing nucleotide polymorphism of the chloroplast, we propose 21 hypervariable regions as potential DNA barcode regions for Myrtales. Phylogenetic analyses showed that Myrtales and its corresponding families are monophyletic, with Combretaceae and the clade of Onagraceae + Lythraceae (BS = 100%, PP = 1) being sister groups. The results of molecular dating showed that the crown of Myrtales was most likely to be 104.90 Ma (95% HPD = 87.88–114.18 Ma), and differentiated from the Geraniales around 111.59 Ma (95% HPD = 95.50–118.62 Ma). Conclusions The chloroplast genome structure of Myrtales is similar to other angiosperms and has a typical four part structure. Due to the expansion and contraction of the IR region, the chloroplast genome sizes in this group are slightly different. The variation of noncoding regions of the chloroplast genome is larger than those of coding regions. Phylogenetic analysis showed that Combretaceae and Onagraceae + Lythraceae were well supported as sister groups. Molecular dating indicates that the Myrtales crown most likely originated during the Albian age of the Lower Cretaceous. These chloroplast genomes contribute to the study of genetic diversity and species evolution of Myrtales, while providing useful information for taxonomic and phylogenetic studies of Myrtales.

Abstract Background The Styracaceae are a woody, dicotyledonous family containing 12 genera and an estimated 160 species. Recent studies have shown that Styrax and Sinojackia are monophyletic, Alniphyllum and Bruinsmia cluster into a clade with an approximately 20-kb inversion in the Large Single-Copy (LSC) region. Halesia and Pterostyrax are not supported as monophyletic, while Melliodendron and Changiostyrax always form sister clades. Perkinsiodendron and Changiostyrax are newly established genera of Styracaceae. However, the phylogenetic relationship of Styracaceae at the generic level needs further research. Results We collected 28 complete plastomes of Styracaceae, including 12 sequences newly reported here and 16 publicly available sequences, comprising 11 of the 12 genera of Styracaceae. All species possessed the typical quadripartite structure of angiosperm plastomes, with sequence differences being minor, except for a large 20-kb (14 genes) inversion found in Alniphyllum and Bruinsmia. Seven coding sequences (rps4, rpl23, accD, rpoC1, psaA, rpoA and ndhH) were identified to possess positively selected sites. Phylogenetic reconstructions based on seven data sets (i.e., LSC, SSC, IR, Coding, Non-coding, combination of LSC + SSC and concatenation of LSC + SSC + one IR) produced similar topologies. In our analyses, all genera were strongly supported as monophyletic. Styrax was sister to the remaining genera. Alniphyllum and Bruinsmia form a clade. Halesia diptera does not cluster with Perkinsiodendron, while Perkinsiodendron and Rehderodendron form a clade. Changiostyrax is sister to a clade of Pterostyrax and Sinojackia. Conclusion Overall, our results demonstrate the power of plastid phylogenomics in improving estimates of phylogenetic relationships among genera. This study also provides insight into plastome evolution across Styracaceae.

Abstract To better identify biodiversity hotspots for conservation on Hainan Island, a tropical island in southern China, we assessed spatial variation in phylogenetic diversity and species richness using 18,976 georeferenced specimen records and a newly reconstructed molecular phylogeny of 957 native woody plants. Within this framework, we delineated bioregions based on vegetation composition and mapped areas of neoendemism and paleoendemism to identify areas of priority for conservation. Our results reveal that the southwest of Hainan is the most important hot spot for endemism and plant diversity followed by the southeast area. The distribution of endemic species showed a scattered, rather than clustered, pattern on the island. Based on phylogenetic range‐weighted turnover metrics, we delineated three major vegetational zones in Hainan. These largely correspond to natural secondary growth and managed forests (e.g., rubber and timber forests) in central Hainan, old‐growth forests and natural secondary growth forest at the margins of Hainan, and nature reserves on the island (e.g., Jianfeng and Diaoluo National Nature Reserves). Our study helps to elucidate potential botanical conservation priorities for Hainan within an evolutionary, phylogenetic framework.

We report and characterize the complete plastome of Lonicera gynochlamydea Hemsl. L. gynochlamydea is a shrub, belonging to the family Caprifoliaceae. Our results show that the length of the complete plastome is 154,643 bp, including 131 genes consisting of 84 protein-coding genes, 39 tRNA genes, and eight rRNA genes. The plastome exhibits the typical quadripartite structure and gene content of angiosperms, composed of two inverted repeats (IRs) regions of 23,846 bp, a large single-copy (LSC) region of 88,298 bp, and a small single-copy (SSC) region of 18,653 bp. The total G/C content in L. gynochlamydea plastome is 38.4%. The complete plastome sequence of L. gynochlamydea will make contributions to the conservation genetics of this species as well as to phylogenetic studies in Caprifoliaceae.

Diospyros nigra (J.F.Gmel.) M.R.Almeida is a rare tree in the family Ebenaceae. The species is native to South America, while having been introduced to Florida and Texas (USA), India, Java and Madagascar. Additionally, this species is distributed in Guangdong Province and the southwest portion of Hainan Province, China. Here, we report and characterize the complete plastome of a cultivar of D. nigra. The length of the complete plastome is 157,168 bp, including 131 genes consisting of 84 protein-coding genes, 37 tRNA genes and 8 rRNA genes. The plastome has the typical structure and gene content of angiosperms, including two inverted repeat (IR) regions of 26,095 bp, a large single copy (LSC) region of 86,610 bp and a small single-copy (SSC) region of 18,386 bp. The total G/C content of the plastome in D. nigra is 37.4%. The complete plastome sequence of D. nigra will make contributions to the conservation genetics of the species, as well as to phylogenetic studies in Ebenaceae.

The complete plastome of G. subelliptica, Merr. 1909. The complete length is 158,356 bp, with the typical structure and gene content of angiosperm plastomes, including a large single-copy region (LSC) of 86,220 bp, a repeat region (IRB), and a reverse repeat region (IRA) of 27,399 bp, respectively, and a small single-copy region (SSC) of 17,338 bp. The plastome contains 130 genes, including 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The total G/C content of the plastome is 36.1%.

Citrus australasica (F. Muell.) Swingle belongs to the family Rutaceae. Citrus australasica is native to eastern Australia and southeastern New Guinea, and is mainly concentrated in a small region of northern New South Wales and tropical rainforest areas in southern Queensland. The complete plastome length of C. australasica is 160,335 bp, with the typical structure and gene content of angiosperm plastids, including a 26,592 bp repeat B (IRB) region, 26,952 bp IRA, 87,678 bp large single copy (LSC) region and 18,756 bp small single copy (SSC) region. The plastid contains 135 genes, including 89 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The total G/C content of the C. australasica plastome is 38.4%. The complete plastome sequence of C. australasica will provide useful resources for conservation genetics research of this species and phylogenetic research of Rutaceae.

Lannea coromandelica (Houtt.) Merr. is a deciduous tree in the family Anacardiaceae, which grows in lowland and hill forests; 100–1800 m. SW Guangdong, S Guangxi, S Yunnan [Bhutan, India, Myanmar, Nepal, Sri Lanka; cultivated elsewhere in continental SE Asia, such as in Cambodia, Laos, Malaysia, Thailand, Vietnam, where it is probably naturalized]. The length of the complete plastome is 162,460 bp, including 130 genes consisting of 85 protein-coding genes, 37 tRNA genes and 8 rRNA genes. The assembled plastome has the typical structure and gene content of angiosperms plastome, which includes two inverted repeats (IRs) regions of 26,877 bp, a large single copy (LSC) region of 89,599 bp and a small single-copy (SSC) region of 19,107 bp. The total G/C content in the plastome of L. coromandelica is 37.7%. The complete plastome sequence of L. coromandelica will provide contributions to the conservation genetics of this species as well as to phylogenetic studies in Anacardiaceae.

Bridelia tomentosa is a deciduous shrub in the family of Phyllanthaceae. It grows in the evergreen primary or secondary thickets or forests in the sea level from 1000 to 1500 m. It distributed in.south China (e.g., Fujian, Guangdong, Guangxi, Hainan etc) and other south Asian countries (e.g. Bangladesh, Bhutan, Cambodia etc). Here, we report and characterize the complete plastome of B. tomentosa. The complete plastome is of 149,958 bp in length with a typical structure and gene content of angiosperm plastome, including two inverted repeat (IRs) regions of 26,354 bp, a large single-copy (LSC) region of 81,355 bp and a small single-copy (SSC) region of 15,895 bp. The plastome contains 129 genes, consisting of 84 protein-coding genes, 37 tRNA genes, eight rRNA genes. The overall G/C content in the plastome of B. tomentosa is 36.0%. The complete plastome sequence of B. tomentosa will provide a useful resource for the conservation genetics of this species as well as for phylogenetic studies in Phyllanthaceae.

The roles of natural and anthropogenic factors in contributing to the organization of biodiversity at large and small scales have long been challenging to disentangle, and doing so has never been attempted for the island province of Hainan in China based on patterns of taxonomic and phylogenetic diversity. Therefore, in this study, we evaluated the taxonomic and phylogenetic diversity of endemic plants on the island as a function of anthropogenic and natural variables based on non-metric multi-dimensional scaling (NMDS) ordination and generated generalized linear models (GLMs). We found that the highest phylogenetic diversity (1006) and the lowest mean phylogenetic distance (515.5) was in the provincial capital, Haikou. The NMDS analyses indicated that taxonomic diversity was significantly correlated with industrial revenue (p = 0.006) and population (p = 0.004). Furthermore, most phylogenetic diversity indices were strongly correlated with population and agricultural revenue, while the sampled natural environmental variables were not significantly correlated with plant diversity indices. These findings indicate that anthropogenic factors are the main present-day driving forces of plant diversity in Hainan, though we did detect a significant latitudinal diversity gradient of richness that likely reflects the historical roles of natural environmental factors in the organization of biodiversity on the island. Overall, our results are alarming for biodiversity of the island and indicate that conservation and sustainable use of endemic plant species must be made a critical priority.

Balakata baccata belongs to the family Euphorbiaceae and is distributed in Yunnan province, China, and other southeast Asian countries, e.g., Bangladesh, Cambodia, India, Indonesia, etc. Here, we report and characterize the complete plastome of B. baccata. The complete plastome is 163,988 bp in length and contains a typical quadripartite structure and gene content found in angiosperms, including two inverted repeat (IR) regions of 27,274 bp, a large single-copy (LSC) region of 90,946 bp and a small single-copy (SSC) region of 18,494 bp. The plastome contains 129 genes, consisting of 84 protein-coding genes, 37 tRNA genes, and eight rRNA genes. The overall G/C content in the plastome of B. baccata is 35.6%. Phylogenetic results show that B. baccata is the earliest diverging lineage of Euphorbioideae. Euphorbia helioscopia + E. esula, E. tirucalli + E. milii and B. baccata have a closer phylogenetic relationship than other taxa within Euphorbiaceae. The complete plastome sequence of B. baccata will provide a useful resource for the conservation genetics of this species as well as for phylogenetic studies in Euphorbiaceae.

Mallotus japonicus is a shrub species in the family of Euphorbiaceae. The study of plastome would be helpful for its phylogenetic study and species identification. The total length of complete plastome for Mallotus japonicus is of 164,912 bp, with typical part-four structure and gene content of angiosperm plastome, including two inverted repeat (IR) regions of 27,829 bp, a large single-copy (LSC) region of 90,319 bp, and a small single-copy (SSC) region of 18,935 bp. The plastome contains 125 genes, consisting of 80 unique protein-coding genes, 31 unique tRNA gene, four unique rRNA genes (5S rRNA, 4.5S rRNA, 16S rRNA, and 23S rRNA), and five pseudogenes. The overall G/C content in the plastome of Mallotus japonicus is 40.2%. The phylogenetic analysis indicates that M. japonicus is closer to M. peltatus than other species in this study. The complete plastome sequence is conducive to the exploitation and utilization of Euphorbiaceae resources and the phylogenetic study in future.

Xylosma longifolia is a tree species within Salicaceae and is distributed in Guizhou, Yunnan, Fujian, Guangxi, Guangdong, and Hainan provinces of China as well as in Vietnam, Laos, and India. There are no studies utilizing the complete plastome of Xylosma longifolia in the current literature. Therefore, this report provides a reference for the plastid gene sequence of Xylosma longifolia, and it contributes to the phylogenetic placement and species identification. In this report, we described the complete plastome sequence of Xylosma longifolia. The complete plastome length of Xylosma longifolia is 156,938 bp and has the typical quadripartite structure and gene content of angiosperms, including two inverted repeat (IR) regions of 27,514 bp, a large single-copy (LSC) region of 85,221 bp and a small single-copy (SSC) region of 16,689 bp. The plastome contains 130 genes, including 86 protein coding genes, 36 tRNA genes, eight rRNA genes (5S rRNA, 4.5S rRNA, 16S rRNA, and 23S rRNA). The GC content of the plastome is 36.8%. The complete plastome sequence will be a valuable resource for studies involving the phylogenetic inference of Salicaceae.

Vernicia montana Lour. is a deciduous tree species belonging to the family of Euphorbiaceae, distributed in southeast Asia. Here, we report and characterize the complete plastome of Vernicia montana Lour. The complete plastome is of 164,506 bp in length with a typical structure and gene content of angiosperm plastome, including two inverted repeat (IRs) regions of 27,965 bp, a large single-copy (LSC) region of 91,427 bp and a small single-copy (SSC) region of 17,149 bp. The plastome contains 130 genes, consisting of 81 protein-coding genes (six of which are repetitive in IR), 38 tRNA genes (seven of which are repetitive in IR), seven rRNA genes (5S rRNA, 4.5S rRNA, 23S rRNA and 16S rRNA) (three of which are repetitive in the IR), and four pseudogenes. The overall G/C content in the plastome of Vernicia montana Lour. is 35.8%. The complete plastome sequence of montana Lour. will provide a useful resource for the conservation genetics of this species as well as for phylogenetic studies in Euphorbiaceae.

Macaranga tanarius (L.) Muell. Arg. is a tree species within Euphorbiaceae, which can be used for building timber and its extract can be used to treat diabetes. In this report, we describe the complete plastome sequence of Macaranga tanarius. The complete plastome of Macaranga tanarius (L.) Muell. Arg. is of 165,362 bp in length, and it is with typical plastome structure and gene content of angiosperm plastome, including two reverse repeat regions (IRs) of 27,503 bp, large single copy region (LSC) of 91,443 bp, and small single copy (SSC) region of 18,913 bp. The plastome contains 131 genes, including 85 protein coding genes, 38 tRNA genes, eight rRNA genes (i.e., 5S rRNA, 4.5S rRNA, 16S rRNA, and 23S rRNA). The total G/C content of Macaranga tanarius (L.) Muell. Arg.plastome is 35.6%. The complete plastome sequence is conducive to the development and utilization of Euphorbiaceae resources and the phylogenetic study.

Flueggea virosa is a tropical plant of the Phyllanthaceae family, which has high medicinal value. Here, we report and characterize the complete plastome of F. virosa. The complete plastome is 154,961 bp in length and contains the typical structure and gene content of angiosperm plastome, including two inverted repeat (IR) regions of 27,575 bp, a large single-copy (LSC) region of 83,397 bp and a small single-copy (SSC) region of 16,414 bp. The plastome contains 130 genes, consisting of 80 unique protein-coding genes, 30 unique tRNA gene, 4 unique rRNA genes (5S rRNA, 4.5S rRNA, 23S rRNA and 16S rRNA). The overall A/T content in the plastome of F. virosa is 63.10%. The complete plastome sequence of F. virosa will provide a useful resource for the conservation genetics of this species as well as for phylogenetic studies in Phyllanthaceae.

Nephelium topengii is an evergreen tree of the Sapindaceae family, which can be used as timber. Here, we report and characterize the complete plastome of N. topengii. The complete plastome is 162,944 bp in length and contains the typical structure and gene content of angiosperm plastome, including two inverted repeat (IR) regions of 30,092 bp, a large single-copy (LSC) region of 85,909 bp and a small single-copy (SSC) region of 16,851bp. The plastome contains 130 genes, consisting of 80 unique protein-coding genes, 30 unique tRNA gene, 4 unique rRNA genes (5S rRNA, 4.5S rRNA, 23S rRNA and 16S rRNA). The overall A/T content in the plastome of N. topengii is 62.30%. The complete plastome sequence of N. topengii will provide a useful resource for the conservation genetics of this species as well as for phylogenetic studies in Sapindaceae.

Cymbidium tortisepalum (Orchidaceae) has been ranked as an endangered (EN) herb species in China. In this study, we report and characterize the complete plastid genome sequence of C. tortisepalum var. longibracteatum in order to provide genomic resources helpful for promoting its conservation and garden utilization. The complete plastome is 150,198 bp in length and contains the typical quadripartite structure of angiosperm, including two Inverted Repeat (IRs) regions of 25,682 bp, a Large Single-Copy (LSC) region of 85,035 bp and a Small Single-Copy (SSC) region of 13,799 bp. The plastome contains 111 genes, consisting of 77 unique protein-coding genes, 30 unique tRNA gene and 4 unique rRNA genes. The overall A/T content in the plastome of C. tortisepalum var. longibracteatum is 62.90%. The complete plastome sequence of C. tortisepalum var. longibracteatum will provide a useful resource for the conservation and garden utilization of this species as well as for the phylogenetic studies of Orchidaceae.

Pseuderanthemum haikangense (Acanthaceae) is a shrubs native to Guangdong, Hainan, Yunnan province of China. In this study, we report and characterize the complete plastome sequence of P. haikangense in order to provide genomic resources helpful for promoting its conservation and medicinal utilization. The complete plastome is 152,849 bp in length and contains the typical quadripartite structure of angiosperm, including two Inverted Repeat (IRs) regions of 25,849 bp, a Large Single-Copy (LSC) region of 83,878 bp and a Small Single-Copy (SSC) region of 17,273 bp. The plastome contains 113 genes, consisting of 79 unique protein-coding genes, 30 unique tRNA gene and 4 unique rRNA genes. The overall A/T content in the plastome of P. haikangense is 61.60%. The complete plastome sequence of P. haikangense will provide a useful resource for the conservation and garden utilization of this species as well as for the phylogenetic studies of Acanthaceae.

Diospyros is the largest genus (about 485 species) in Ebenaceae. It is a deciduous or evergreen tree or shrub. It grows in pantropical and extending into temperate regions. Here, we report and characterize the complete plastid genome sequences of D. maclurei Merr. and D. hainanensis Merr. in an effort to provide genomic resources useful for promoting their systematics research and potential economic development. The complete plastome of D. maclurei is 157,946 bp in length, including two Inverted Repeat (IR) regions of 26,081 bp, a Large Single-Copy (LSC) region of 87,387 bp, and a Small Single-Copy (SSC) region of 18,397 bp. The plastome contains 114 genes, consisting of 80 unique protein-coding genes, 30 unique tRNA genes, and four unique rRNA genes. The overall A/T content in the plastome of D. maclurei is 62.60%. The complete plastome of D. hainanensis is 157,999 bp in length, including two Inverted Repeat (IR) regions of 26,077 bp, a Large Single-Copy (LSC) region of 87,523 bp, and a Small Single-Copy (SSC) region of 18,322 bp. The plastome contains 114 genes, consisting of 80 unique protein-coding genes, 30 unique tRNA genes, and four unique rRNA genes. The overall A/T content in the plastome of D. hainanensis is 62.60%. The complete plastome sequences of D. Maclurei and D. hainanensis will provide a useful resource for the conservation genetics of the two species as well as for the phylogenetic studies of Diospyros.

The Sino-Japanese Floristic Region (SJFR) is a key area for plant phylogeographical research, due to its very high species diversity and disjunct distributions of a large number of species and genera. At present, the root cause and temporal origin of the discontinuous distribution of many plants in the Sino-Japanese flora are still unclear. Diabelia (Caprifoliaceae; Linnaeoideae) is a genus endemic to Asia, mostly in Japan, but two recent discoveries in China raised questions over the role of the East China Sea (ECS) in these species' disjunctions. Chloroplast DNA sequence data were generated from 402 population samples for two regions (rpl32-trnL, and trnH-psbA) and 11 nuclear microsatellite loci were screened for 549 individuals. Haplotype, population-level structure, combined analyses of ecological niche modeling, and reconstruction of ancestral state in phylogenies were also performed. During the Last Glacial Maximum (LGM) period after the Tertiary, Diabelia was potentially widely distributed in southeastern China, the continental shelf of the East China Sea and Japan (excluding Hokkaido). After LGM, all populations in China have disappeared except those in Zhejiang which may represent a Glacial refuge. Populations of Diabelia in Japan have not experienced significant bottleneck effects, and populations have maintained a relatively stable state. The observed discontinuous distribution of Diabelia species between China and Japan are interpreted as the result of relatively ancient divergence. The phylogenetic tree of chloroplast fragments shows the characteristics of multi-origin evolution (except for D. sanguinea). STRUCTURE analysis of nuclear Simple Sequence Repeat (nSSR) showed that the plants of the Diabelia were divided into five gene pools: D. serrata, D. spathulata, D. sanguinea, D. ionostachya (D. spathulata var. spathulata-Korea), and populations of D. ionostachya var. ionostachya in Yamagata prefecture, northern Japan. Molecular evidence provides new insights of Diabelia into biogeography, a potential glacial refuge, and population-level genetic structure within species. In the process of species differentiation, ECS acts as a corridor for two-way migration of animals and plants between China and Japan during glacial maxima, providing the possibility of secondary contact for discontinuously distributed species between China and Japan, or as a filter (creating isolation) during glacial minima. The influence of the ECS in speciation and biogeography of Diabelia in the Tertiary remains unresolved in this study. Understanding origins, evolutionary histories, and speciation will provide a framework for the conservation and cultivation of Diabelia.

Urban green spaces provide a host of ecosystem services, the quantity and structure of which play an important role in human well-being. Rapid urbanization may modify urban green spaces, having various effects on plant diversity. Tropical coastal cities have urbanized rapidly in recent decades, but few studies have been conducted with a focus on their green spaces. We studied the responses of cultivated and spontaneous plants, both key components of urban flora, to the landscape structure of urban green spaces and possible social drivers. We analyzed existing relationships between plant diversity indices, urban green space landscape metrics (using Systeme Probatoire d’Observation de la Terre (SPOT) data,), and social factors, including the type, population density, construction age, and GPS coordinates of each Urban Functional Unit, or UFU. We found that UFUs with more green space patches had higher cultivated and spontaneous species richness than those with fewer green space patches. Spontaneous species richness decreased when green space patches became fragmented, and it increased when green space patches were more connected (e.g., via land bridges). Conversely, cultivated species richness increased with green space patch fragmentation. The phylogenetic diversity of both cultivated and spontaneous plants were weakly associated with green space structure, which was strongly driven by land use. Old UFUs and those with larger populations had more green space patches overall, although they tended to be small and fragmented. Green space patch density was found to increase as the UFU age increased. From the viewpoint of knowledge transfer, understanding the effects and drivers of landscape patterns of urban green spaces could inform the development of improved policies and management of urban green space areas.

Understanding the factors that drive green space composition and richness in heterogeneous urban landscapes is critical for maintaining important ecosystem services and biodiversity. Few studies have been conducted on urban greening and plant diversity at the urban functional unit (UFU) level, although a handful of studies have explored the drivers of greening percentage and its relationships with plant richness in tropical cities. In this study, we conducted field surveys, compiled census and remote sensing data, and performed spatial analyses to investigate the interrelationship between greening percentages, plant diversity, and the socioeconomic variables of different primary and secondary UFUs in the cities of Beijing, Zhanjiang, and Haikou in China. We found that these relationships did not differ significantly between primary and secondary UFUs, and that Parks represented the largest areas of forested land, grassland, and water bodies across all three cities. Moreover, the greening percentages of all UFUs across these three cities were positively correlated with both socioeconomic variables and plant species richness. These relationships can be utilized to guide future green space planning within urban ecosystems.

Magnolia fordiana var. hainanensis (Dandy) Noot. (Magnoliaceae) is an endemic and ornamental tree distributed in Hainan, China. In this study, we report and characterize the complete plastid genome sequence of M. fordiana var. hainanensis in order to provide genomic resources helpful for promoting its conservation and garden utilization. The complete plastome is 160,157 bp in length and contains the typical quadripartite structure of angiosperm, including two Inverted Repeat (IRs) regions of 26,573 bp, a Large Single-Copy (LSC) region of 88,255 bp and a Small Single-Copy (SSC) region of 18,756 bp. The plastome contains 114 genes, consisting of 80 unique protein-coding genes, 30 unique tRNA gene and 4 unique rRNA genes. The overall A/T content in the plastome of M. fordiana var. hainanensis is 60.70%. The complete plastome sequence of M. fordiana var. hainanensis will provide a useful resource for the conservation and garden utilization of this species as well as for the phylogenetic studies of Magnoliaceae.

Croton laevigatus grows as an evergreen tree or shrub with 15 meters height. It is distributed in the dense or open forests of Hainan province, China. Here, we report and characterize the complete plastome of C. laevigatus in an effort to provide genomic resources useful for promoting its systematics research. The plastome of C. laevigatus is found to possess a total length 162,515 bp with the typical quadripartite structure of angiosperms, contains two Inverted Repeats (IRs) of 26,866 bp, a Large Single-Copy (LSC) region of 90,234 bp and a Small Single-Copy (SSC) region of 18,549 bp. The plastome contains 113 genes, consisting of 79 unique protein-coding genes, 30 unique tRNA genes and four unique rRNA genes. The overall A/T content in the plastome of C. laevigatus is 64.10%. The phylogenetic analysis indicated that C. laevigatus is close to C. tiglium within Euphorbiaceae in this study. The complete plastome sequence of C. laevigatus will provide a useful resource for the conservation genetics of this species as well as for the phylogenetic studies of Euphorbiaceae.

Euphorbia milii (Euphorbiaceae) grows as a scrambling shrub with many branches. Here, we report and characterize the complete plastome of E. milii in an effort to provide genomic resources useful for promoting its systematic research. The plastome of E. milii is found to possess a total length of 160,806 bp with the typical quadripartite structure of angiosperms, contains two Inverted Repeats (IRs) of 26,695 bp, a Large Single-Copy (LSC) region of 90,211 bp and a Small Single-Copy (SSC) region of 17,205 bp. The plastome contains 114 genes, consisting of 80 unique protein-coding genes, 30 unique tRNA genes and four unique rRNA genes. The overall A/T content in the plastome of E. milii is of 64.10%. The phylogenetic analysis indicated that E. milii is close to E. tirucalli within Euphorbiaceae in this study. The complete plastome sequence of E. milii will provide a useful resource for the conservation genetics of this species as well as for the phylogenetic studies of Euphorbiaceae.

Elaeagnus glabra is an evergreen vine or climbing shrub with 5 m height. It is widespread in southern China. It grows in the sunny forests or forest margins below 1000 m a.s.l. In this paper, we report and describe the complete plastome of E. glabra in order to provide useful genomic data for its systematic research. The complete plastome of E. glabra is 152,555 bp with a typical quadripartite structure of angiosperms. It contains two Inverted Repeats (IRs) of 25,918 bp, a large single-copy (LSC) of 82,408 bp, and a small single-copy (SSC) region of 18,311 bp. The complete plastome contains 129 genes, including 83 protein-coding genes, 38 tRNA genes, and eight rRNA genes. The overall A/T content in the chloroplast genome of E. glabra is 62.90%. The phylogenetic analysis indicated that E. glabra is close to E. loureirii within Elaeagnaceae. The complete plastome of E. glabra will provide useful resources for the development and utilization of this species and the phylogenetic study of Rosales.

Mallotus peltatus is a tropical plant of the Euphorbiaceae family, which could be used as a beverage and medicine in Hainan, China. Here, we report and characterize the complete plastome of M. peltatus. The complete plastome is 163,304 bp in length and contains a typical structure and gene content of angiosperm plastome, including two inverted repeat (IR) regions of 27,112 bp, a large single-copy (LSC) region of 89,886 bp and a small single-copy (SSC) region of 18,840 bp. The plastome contains 131 genes, consisting of 78 unique protein-coding genes, 30 unique tRNA gene, four unique rRNA genes (5S rRNA, 4.5S rRNA, 23S rRNA and 16S rRNA), and eight pseudogenes. The overall A/T content in the plastome of M. peltatus is 64.02%. The complete plastome sequence of M. peltatus will provide a useful resource for the conservation genetics of this species as well as for phylogenetic studies in Euphorbiaceae.

Magnolia omeiensis is an evergreen tree with 25 meters heights. It is distributed in tropical 1200–1300 m. Mount Emei. And it has been ranked as a CR (Critically Endangered) species in China. Here, we report and characterize the complete plastome of M. omeiensis in an effort to provide genomic resources useful for promoting its systematics research. The plastome of M. omeiensis is found to possess a total length 160,021 bp with the typical quadripartite structure of angiosperms, contains two Inverted Repeats (IRs) of 26,336 bp, a Large Single-Copy (LSC) region of 88,061 bp and a Small Single-Copy (SSC) region of 19,288 bp. The plastome contains 114 genes, consisting of 80 unique protein-coding genes, 30 unique tRNA genes and 4 unique rRNA genes. The overall A/T content in the plastome of M. omeiensis is 60.70%. The phylogenetic analysis indicated that M. omeiensis is close to Magnolia yunnanensis within Magnoliaceae in this study. The complete plastome sequence of M. omeiensis will provide a useful resource for the conservation genetics of this species as well as for the phylogenetic studies of Magnoliaceae.

iThe plastome of Manilkara zapota is found to be 158,386 bp long with the typical quadripartite structure of angiosperms, contains two inverted repeats (IRs) of 26,099 bp each, a large single-copy (LSC) region of 87,745 bp, and a small single-copy (SSC) region of 18,443 bp. The plastome contains 114 genes, consisting of 80 unique protein-coding genes, 30 unique tRNA genes, and 4 unique rRNA genes. The overall A/T content in the plastome of M. zapota is 63.00%. The phylogenetic analysis indicated that M. zapota is close to Sideroxylon wightianum within Sapotaceae in this study.

Jacaranda mimosifolia is a deciduous arbor with blue flowers native to Brazil, Bolivia, and Argentina in South America. After introduction from South America, it was widely cultivated as a garden ornamental plant in South China. The complete chloroplast (cp) genome sequence of this ornamental species is reported in this study, based on high-throughput sequencing (Illumina). The complete cp genome is 153,514 bp in length, containing a pair of inverted repeat regions (IRs) of 25,408 bp, a large single-copy (LSC) region of 84,755 bp, and a small single-copy (SSC) region of 17,943 bp. The cp genome contains 130 genes, consisting of 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The overall A/T content in the cp genome of J. mimosifolia is 61.70%. The phylogenetic analyses indicate that there is a close relationship between J. mimosifolia and Tecomaria capensis. The complete cp sequence of J. mimosifolia will provide a useful resource for the development and utilization of this species as well as for the phylogenetic studies in Bignoniaceae.

Anthropogenic processes and socio-economic factors play important roles in shaping plant diversity in urban parks. To investigate how plant diversity of Ma' anling urban volcano park in Hainan Province, China respond to these factors, we carried out a field investigation on the taxonomic and phylogenetic diversity of vascular plants and soil properties in this area. We found 284 species of vascular plants belonging to 88 families and 241 genera, which included 194 native species, 23 invasive species, 31 naturalized species, 40 cultivars, and 4 rare / endangered plant species. Tree composition and richness significantly varied between different vegetation formations (plantation, secondary forest, and abandoned land). Plant species richness and community composition were significantly affected by elevation (El), soil water content (WC), total soil nitrogen (TN) and soil organic matter (SOM). There were significant diversity differences between plantations and abandoned lands, but not between the plantations and secondary forests. The flora in the study site was tropical in nature, characterized by pantropic distributions. Compared to adjacent areas, floristic composition in the study site was most similar to that of Guangdong, followed by that of Vietnam. Our study revealed the diversity patterns of volcanic plants and provided the basis for future planning of plant conservation, such as preserving plant species, maintaining plant habitats, and coordinating plant management in this region.

[This corrects the article DOI: 10.1371/journal.pone.0198517.].

Environmental impact assessment (EIA) before and after the establishment of a Water Conservancy Project (WCP) is of great theoretical and practical importance for assessing the effectiveness of ecological restoration efforts. WCPs rehabilitate flood-damaged areas or other regions hit by disasters by controlling and redistributing surface water and groundwater. Using Geographic Information System (GIS) and Composite Evaluation Index (CEI) in predictive modeling, we studied the degree to which a WCP could change land use, plant communities, and species diversity in Yunnan, China. Via modeling, we quantified likely landscape pattern changes and linked them to naturality (i.e., the percentage of secondary vegetation types), diversity, and stability together with the human interferences (e.g., conservation or restoration project) of an ecosystem. The value of each index was determined by the evaluation system, and the weight percentage was decided through Analytical Hierarchy Process (AHP). We found that minor land-use changes would occur after the Chaishitan WCP was theoretically established. The greatest decline was farmland (0.079%), followed by forest (0.066%), with the least decline in water bodies (0.020%). We found 1,076 vascular plant species (including subspecies, varieties and form) belonging to 165 families and 647 genera in Chaishitan irrigation area before the water conservancy establishment. The naturality and diversity decreased 11.18 and 10.16% respectively. The CEI was 0.92, which indicated that Chaishitan WCP will enhance local landscape heterogeneity, and it will not deteriorate local ecological quality. Our study proposes a comprehensive ecological evaluation system for this WCP and further suggests the importance of including the ecological and environmental consequences of the WCP, along with the well-established socioeconomic evaluation systems for non-natural reserve areas. We conclude that the Chaishitan WCP will have minor environmental impacts on the local landscape and plant diversity. Furthermore, the irrigation project will provide sufficient water once established, which will enrich local plant diversity; therefore, we support its construction.

Clinacanthus nutans (Burm.f.) Lindau. is a medicinal species occurring in southern Guangdong province, Guangxi province, Hainan province and Yunnan province of China, which has been widely used in the medical field. However, its complete plastome information and systematic position are still unknown. In order to enhance the development of its medicinal value, we report and characterize the complete plastid genome sequence of C. nutans in an effort to provide genomic resources useful to promoting its medicinal value and systematic research. The complete plastome is 151,669 bp in length and contains the typical structure and gene content of angiosperm plastome, including two Inverted Repeat (IR) regions of 25,366 bp, a Large Single-Copy (LSC) region of 83,502 bp and a Small Single-Copy (SSC) region of 17,435 bp. The plastome contains 113 genes, consisting of 80 unique protein-coding genes, 29 unique tRNA gene and four unique rRNA genes (5S rRNA, 4.5S rRNA, 23S rRNA and 16S rRNA). The overall A/T content in the plastome of C. nutans is 61.60%. The complete plastome sequence of C. nutans will provide a useful resource for the conservation genetics of this species as well as for the phylogenetic studies of Acanthaceae.

Pandanus tectorius Parkinson ex Du Roi (Pandanaceae) is a tree or shrub which is widely distributed in seashores and sandy beaches in Fujian, Guangdong, Guangxi, Guizhou, Hainan, Taiwan, Yunnan Provinces of China. P. tectorius sometimes is used as a living fence, the leaves are used for weaving and the fruit is beneficial for the treatment of diabetes. Here, we report and characterize the complete plastid genome sequence of P. tectorius in an effort to provide genomic resources useful for promoting its conservation. The complete plastome is 159,362 bp in length and contains the typical structure and gene content of angiosperm plastome, including two inverted repeat (IR) regions of 26,702 bp, a large single-copy (LSC) region of 87,447 bp and a small single-copy (SSC) region of 18,511 bp. The plastome contains 114 genes, consisting of 80 unique protein-coding genes, 30 unique tRNA genes, and 4 unique rRNA genes (5S rRNA, 4.5S rRNA, 23S rRNA, and 16S rRNA). The overall A/T content in the plastome of P. tectorius is 62.40%. The complete plastome sequence of P.tectorius will provide a useful resource for the conservation genetics of this species as well as for the phylogenetic studies of Pandanaceae.

Dillenia indica Linn. is an endangered plant species occurring in southern Guangxi province and Yunnan province of China, which has been grown in gardens as an ornamental plant and is widely used in the medical field. Here, we report and characterize the complete plastid genome sequence of D. indica to provide genomic resources useful for promoting its conservation. The complete plastome is 159,266 bp in length and contains the typical structure and gene content of angiosperm plastome, including two inverted repeat (IR) regions of 26,457 bp, a large single-copy (LSC) region of 88,305 bp, and a small single-copy (SSC) region of 18,047 bp. The plastome contains 115 genes, consisting of 81 unique protein-coding genes, 30 unique tRNA genes, and 4 unique rRNA genes (5S rRNA, 4.5S rRNA, 23S rRNA, and 16S rRNA). The overall A/T content in the plastome of D. indica is 63.40%. The complete plastome sequence of D. indica will provide a useful resource for the conservation genetics of this species as well as for the phylogenetic studies of Dilleniaceae.

Heptacodium miconioides Rehd. is a rare and endangered plant species occurring in Anhui, Hubei, and Zhejiang Provinces of China, which is endemic to China. Here, we report and characterize the complete plastid genome sequence of H. miconioides in an effort to provide genomic resources useful for promoting its conservation. The complete plastome is 156,313 bp in length and contains the typical structure and gene content of angiosperm plastome, including two inverted repeat (IR) regions of 23,904 bp, a large single-copy (LSC) region of 89,760 bp and a small single-copy (SSC) region of 18,745 bp. The plastome contains 114 genes, comprising 79 unique protein-coding genes, 31 unique tRNA genes, and 4 unique rRNA genes (5S rRNA, 4.5S rRNA, 23S rRNA, and 16S rRNA). The overall A/T content in the plastome of D. indica is 61.60%. The complete plastome sequence of H. miconioides will provide a useful resource for the conservation genetics of this species as well as for the phylogenetic studies of Caprifoliaceae.

Syzygium forrestii Merr. et Perry is an evergreen broad-leaved tree, 8–15 metres tall. It is mainly distributed in the Southwest of China (Nu river valley to Xishuangbanna area), growing from 800 to 2400 metres above sea level. It grows in the evergreen broad-leaved forest and the hillside shrubbery. It is an endemic plant species in China. At present, it has not been artificially introduced and cultivated. However, its complete plastome information and systematic position is still unknown. Here we report and characterize the complete plastid genome sequence of S. forrestii in an effort to provide genomic resources useful for promoting its conservation and systematic research. The complete plastome is 159,996 bp in length and contains the typical structure and gene content of angiosperm plastome, including two inverted repeat (IR) regions of 26,414 bp, a large single-copy (LSC) region of 88,560 bp and a small single-copy (SSC) region of 18,608 bp. The plastome contains 115 genes, consisting of 81 unique protein-coding genes, 30 unique tRNA gene and 4 unique rRNA genes (5S rRNA, 4.5S rRNA, 23S rRNA and 16S rRNA). The overall A/T content in the plastome of S. forrestii is 63.10%. The complete plastome sequence of S. forrestii will provide a useful resource for the conservation genetics of this species as well as for the phylogenetic studies of Myrtaceae.

Homalium (Salicaceae) is mainly distributed in tropical and subtropical regions. Here we report and characterize the complete plastid genome sequences of Homalium paniculiflorum, H. stenophyllum, and H. ceylanicum in an effort to provide genomic resources useful for promoting its systematics research. The plastomes of H. paniculiflorum, H. stenophyllum, and H. ceylanicum were found to possess a total length 157,206 bp, 156,395 bp, and 156,551 bp, respectively. They all have typical quadripartite structure of angiosperms, containing two Inverted Repeats (IRs) of 27,796 bp in H. paniculiflorum, 27,669 in H. stenophyllum and 27,639 bp in H. ceylanicum, a Large Single-Copy (LSC) region of 85,031 bp (H. paniculiflorum), 84,458 bp (H. stenophyllum) and 84,627 bp (H. ceylanicum), a Small Single-Copy (SSC) region of 16,584 bp (H. paniculiflorum), 16,599 bp (H. stenophyllum), and 16,646 bp (H. ceylanicum). The all plastome contains 111 genes, consisting of consisting of 77 unique protein-coding genes (seven of which are duplicated in the IR), 30 unique tRNA genes (seven of which are duplicated in the IR) and 4 unique rRNA genes. The overall A/T content in the plastomes of H. paniculiflorum, H. stenophyllum, and H. ceylanicum are 63.30, 63.20, and 63.20%. The complete plastome sequences of H. paniculiflorum, H. stenophyllum, and H. ceylanicum will provide a useful resource for the conservation genetics of the three species as well as for the phylogenetic studies of Homalium.

Antirhea chinensis is a plant of the family Rubiaceae. So far, there is no study on the genome of A. chinensis. Here we report and characterize the complete plastid genome sequence of A. chinensis in an effort to provide genomic resources useful for promoting its conservation. The complete plastome is 155,616 bp in length and contains the typical structure and gene content of angiosperm plastome, including two inverted repeat regions of 25,690 bp, a large single copy region of 86,252 bp and a small single copy region of 17,984 bp. The plastome contains 114 genes, consisting of 80 unique protein-coding genes, 30 unique tRNA genes, and 4 unique rRNA genes. The overall A/T content in the plastome of A. chinensis is 62.40%. The complete plastome sequence of A. chinensis will provide a useful resource for the conservation genetics of this species as well as for the phylogenetic studies for Rubiaceae.

Saprosma merrillii is a plant of the family Rubiaceae. So far, there is no study on the genome of S. merrillii. Here, we report and characterize the complete plastid genome sequence of S. merrillii in an effort to provide genomic resources useful for promoting its conservation. The complete plastome is 155,820 bp in length and contains the typical structure and gene content of angiosperm plastome, including two Inverted Repeat (IR) regions of 26,228 bp, a Large Single-Copy (LSC) region of 85,625 bp and a Small Single-Copy (SSC) region of 17,739 bp. The plastome contains 114 genes, consisting of 80 unique protein-coding genes, 30 unique tRNA genes, and 4 unique rRNA genes. The overall A/T content in the plastome of S. merrillii is 62.50%. The complete plastome sequence of S. merrillii will provide a useful resource for the conservation genetics of this species as well as for the phylogenetic studies for Rubiaceae.

Arisaema ringens is a dioecious herb of the family Araceae. So far, there have been no studies on the genome of A. ringens. Here we report and characterize the complete plastid genome sequence of A. ringens in an effort to provide genomic resources useful for promoting its conservation. The complete plastome is 160,792 bp in length and contains the typical structure and gene content of angiosperm plastome, including two inverted repeat regions of 25,312 bp, a large single copy region of 88,915 bp, and a small single copy region of 21,253 bp. The plastome contains 114 genes, consisting of 80 unique protein-coding genes, 30 unique tRNA genes, and 4 unique rRNA genes. The overall A/T content in the plastome of A. ringens is 63.50%. The complete plastome sequence of A. ringens will provide a useful resource for the conservation genetics of this species as well as for the phylogenetic studies for Araceae.

Hedyotis ovata is a plant of the family Rubiaceae. So far, there is no study on the genome of H. ovata. Here, we report and characterize the complete plastid genome sequence of H. ovata in an effort to provide genomic resources useful for promoting its conservation. The complete plastome is 154,560 bp in length and contains the typical structure and gene content of angiosperm plastome, including two inverted repeat (IR) regions of 26,058 bp, a large single-copy (LSC) region of 84,579 bp and a small single-copy (SSC) region of 17,865 bp. The plastome contains 114 genes, consisting of 80 unique protein-coding genes, 30 unique tRNA genes, and 4 unique rRNA genes. The overall A/T content in the plastome of H. ovata is 61.90%. The complete plastome sequence of H. ovata will provide a useful resource for the conservation genetics of this species as well as for the phylogenetic studies for Rubiaceae.