Banksia L.f., an iconic genus of the Proteaceae, is endemic to Australia, with its highest species richness and phylogenetic diversity (PD) in southwestern Western Australia. Analysis of the phylogenetic component of richness and endemism uncovered important patterns of Banksia evolutionary history that are not seen at the species level. We found that Banksia is significantly phylogenetically clustered in this region, likely due to recent evolutionary radiations. We also found significant concentrations of phylogenetic endemism in this region, both neoendemism (short, range-restricted evolutionary branches) and paleoendemism (long, range-restricted evolutionary branches). There is a striking northwest to southeast divide in phyloturnover in southwestern Western Australia. The majority of the variation in turnover patterns can be explained by environmental factors, with climate representing the largest covariate. This study adds to the growing body of evidence that indicates the importance of integrating phylogenetic and biodiversity data to inform conservation planning.

Studies on large-scale geographic patterns of aquatic plant diversity can promote research on the generality of macroecological patterns in different ecosystems. Here, we compiled a checklist of 889 aquatic angiosperms in China, including 738 helophytes (emergent and marshy plants) and 151 hydrophytes (submerged, free-floating, and floating-leaved plants). We explore the geographic patterns and environmental correlates of aquatic plant diversity based on six metrics including species richness (SR), weighted endemism (WE), phylogenetic diversity (PD), phylogenetic endemism (PE), the standardized effect size of phylogenetic diversity (PDses), and the standardized effect size of mean phylogenetic distance (MPDses). Our results show that the diversity of aquatic plants in China is extremely uneven, with high diversity in southeastern China and low diversity in northwestern China, and the geographic patterns of taxonomic and PD are generally consistent. The pattern of helophytes differs from that of hydrophytes. Notably, the wavy-shaped pattern of aquatic plant diversity (especially SR and PD for hydrophytes) across the latitude observed in this study is not consistent with those previously observed for aquatic plants in other continents. Climatic variables and water environmental variables are the main drivers of aquatic plant diversity in China; however, the effects of individual variables differ between helophytes and hydrophytes. Water environmental variables have a greater impact on PDses and MPDses of hydrophytes than those of helophytes. Overall, our work provides insight into understanding the large-scale patterns of aquatic plant diversity and is a critical addition to previous studies on the macroecological pattern of terrestrial organisms.

Crassulaceae is a mid-sized family of angiosperms, most species of which are herbaceous succulents, usually with 5-merous flowers and one or two whorls of stamens. Although previous phylogenetic studies revealed seven major “clades” in Crassulaceae and greatly improved our understanding of the evolutionary history of the family, relationships among major clades are still contentious. In addition, the biogeographic origin and evolution of important morphological characters delimiting infrafamilial taxa have not been subject to formal biogeographic and character evolution analyses based on a well-supported phylogeny backbone. In this study, we used plastomic data of 52 species, representing all major clades revealed in previous studies to reconstruct a robust phylogeny of Crassulaceae, based on which we unraveled the spatiotemporal framework of diversification of the family. We found that the family may originate in southern Africa and then dispersed to the Mediterranean, from there to eastern Asia, Macaronesia, and North America. The crown age of Crassulaceae was dated at ca. 63.93 million years ago, shortly after the Cretaceous–Paleogene (K-Pg) boundary. We also traced the evolution of six important morphological characters previously used to delimit infrafamilial taxa and demonstrated widespread parallel and convergent evolution of both vegetative (life form and phyllotaxis) and floral characters (number of stamen whorls, petals free or fused, and flower merism). Our results provide a robust backbone phylogeny as a foundation for further investigations, and also some important new insights into biogeography and evolution of the family Crassulaceae.

Previous phylogenetic analyses indicated that Polygonoideae, the largest subfamily in the Polygonaceae, is monophyletic. Phylogenetic relationships within the Polygonoideae have been substantially controversial. We collected 160 samples representing all currently recognized tribes for a more comprehensive phylogenetic analysis of the subfamily. Here, we reconstructed phylogenetic relationships of the Polygonoideae, inferred ancestral character states, and estimated the divergence time with a dense taxon sampling. This study corroborated and expanded previous results regarding the phylogenetic relationships of the Polygonoideae clade, and resolved the phylogenetic status of some controversial taxa by integrating molecular and morphological evidence. Phylogenetic analyses based on the complete plastomes suggested strong support for six primary clades that correspond to the most recent circumscription of tribes: Polygoneae, Rumiceae, Calligoneae, Pteroxygoneae, Fagopyreae, and Persicarieae. In addition, we provided further morphological data and assessed characters that supported different clades. The 3-colpate pollen, 5-parted perianth, and 3 styles were inferred to be the ancestral states of Polygonoideae. Divergence time estimation revealed that Polygonoideae originated around the late Cretaceous, and diversification was concentrated in the Eocene and Miocene. Time estimation indicated that the rapid uplift of the Tibetan Plateau and the intensification of the Asian monsoons might be potential driving forces for the diversification of Polygonoideae. Overall, this study advances our understanding of the phylogeny and diversification of the Polygonoideae and highlights the adaptive evolution of the taxa.

Disjunct distribution is a key issue in biogeography and ecology, but it is often difficult to determine the relative roles of dispersal vs. vicariance in disjunctions. We studied the phylogeographic pattern of the monotypic Conandron ramondioides (Gesneriaceae), which shows Sino-Japanese disjunctions, with ddRAD sequencing based on a comprehensive sampling of 11 populations from mainland China, Taiwan Island, and Japan. We found a very high degree of genetic differentiation among these three regions, with very limited gene flow and a clear Isolation by Distance pattern. Mainland China and Japan clades diverged first from a widespread ancestral population in the middle Miocene, followed by a later divergence between mainland China and Taiwan Island clades in the early Pliocene. Three current groups have survived in various glacial refugia during the Last Glacial Maximum, and experienced contraction and/or bottlenecks since their divergence during Quaternary glacial cycles, with strong niche divergence between mainland China+Japan and Taiwan Island ranges. Thus, we verified a predominant role of vicariance in the current disjunction of the monotypic genus Conandron. The sharp phylogenetic separation, ecological niche divergence among these three groups, and the great number of private alleles in all populations sampled indicated a considerable time of independent evolution, and suggests the need for a taxonomic survey to detect potentially overlooked taxa.

Resolving the infrageneric classification of species-rich genera has been challenging in plant taxonomy. Ilex L. is a subcosmopolitan genus with over 600 species of dioecious trees and shrubs. Many classification systems based on morphological data have been proposed during the past 250 years. However, these systems (such as Loesener's and Galle's systems) may not truly reflect Ilex's evolutionary trajectories because most of those system's infrageneric hierarchies are not monophyletic. In this study, we reconstructed a phylogeny of Ilex L. comprising 15 moderately to highly supported clades using rigorously identified samples (202 species) and closely authenticated gene sequences of three nuclear genes [internal transcribed spacer (ITS), external transcribed spacer (ETS), and nepGS]. The newly generated phylogenetic tree resembles essentially that of the nuclear tree of Manen et al., but shows conspicuous topological differences with the phylogeny of Yao et al. Closely scrutinizing morphological variation and distributional patterns of 202 species, this study found that most lineages of Ilex identified herein are well defined by a particular trait or a combination of morphological and distributional traits, displaying phylogeny–morphology–distribution conformity that has seldom been uncovered in previous studies. Given the general phylogeny–morphology–distribution conformity revealed in this genus, we put forward an updated sectional classification system for Ilex that temporarily contains 14 sections. The new classification will provide a robust framework for studying the evolution and diversification of this ecologically and economically important genus.

Gomphomastacinae is a grasshopper subfamily in Eumastacidae, with a morphology and distribution distinct from other subfamilies. The alpine genera of Gomphomastacinae that inhabit the Qinghai–Tibet Plateau in China show unique characteristics adapted to high-altitude life. However, their phylogenetic position and biogeographic history remain controversial. Thus, to determine the diversification history of these alpine genera and the origin of the subfamily, we obtained mitochondrial genome sequences from all seven Gomphomastacinae genera distributed in China. The reconstructed phylogeny was well supported and confirmed the phylogenetic position of Gomphomastacinae within Eumastacidae. Time calibration revealed a deep-time origin of the subfamily dating back to the Cretaceous period, and the diversification among alpine genera was also an ancient pre-Miocene event (30–50 Ma). Based on phylogeny and time estimates, the most likely biogeographic scenario is that Gomphomastacinae originated from an ancestral lineage that lived in East Gondwana and dispersed to Central and Western Asia through India. Subsequently, the alpine genera likely diverged along with the uplift of the Qinghai–Tibet Plateau and survived drastic climate change by in situ adaptation to high-altitude dwellings.

Eudicots exhibit diverse life forms and occupy a wide variety of habitats in the modern terrestrial ecosystems, and the diversification began during the Early Cretaceous; however, few Early Cretaceous fossils are preserved as multiorgan whole plants that can provide sufficient morphological characters for detailed phylogenetic assessment. Here, Fairlingtonia microgyna sp. nov. is reported from the upper Lower Cretaceous of Zhonggou Formation, Hanxia Section, Yumen City, western Gansu Province, Northwest China. The specimen is exceptionally preserved as multiorgan whole plant fossil with fibrous adventitious roots, simple and deeply dissected leaves, solitary and dehiscent capsular fruits attached to the creeping stems. As such, it was interpreted as a herbaceous eudicot. Phylogenetic analyses support a placement within the Papaveraceae, most likely in Papaveroideae, but there are obvious differences in morphological characteristics, which cannot confirm the systematic position within the Papaveraceae. Fossil records of Fairlingtonia from contemporaneous deposits (late Aptian to early Albian) in Northwest China and eastern North America provide direct evidence of the geographical radiation of Fairlingtonia on Laurasia. And the morphological characters of F. microgyna, including creeping leafy branches, fibrous adventitious roots, small and deeply dissected leaves as well as small capsular fruits with tiny seeds probably indicate that it was a colonizer of lake-shore environments under wet and bright conditions and possessed fast-growing and rapid propagation habitats, which allowed it to expand its geographic range with both sexual and asexual reproduction.

The Ventilago Gaertn. (Rhamnaceae) is widely distributed in pantropical areas of Africa, Asia, and Australia. However, fossil records of this taxon are sparse, which limits understanding of the evolution and biogeographic history of the genus. In the present study, we report and describe two new fossil species of Ventilago, V. siwalika sp. nov. from the Miocene sediments of Himachal Pradesh, western Himalaya, and V. pliocenica sp. nov. from the Pliocene sediments of Jharkhand, eastern India based on single-winged samaras. Ventilago pliocenica is characterized by a prominent midvein, obtuse to sub-round apex with mucronate tip, longitudinal secondary veins extending the full length of the fruit, and reticulate nature of higher-order veins, the presence of equatorial rim, the hypanthium, and short pedicel. On the other hand, V. siwalika is characterized by a prominent midvein, obtuse to sub-round apex with mucronate tip, longitudinal secondary veins extending the full length of the fruit, and reticulate nature of higher-order veins. Our discovery represents the first unambiguous fossil record of single-winged samara of Ventilago from India and provides valuable insights into the evolution of this genus. In this paper, we also review its biogeographic history and add new information to understand its hypothetical migration route. Present and earlier records of Ventilago also suggest that this genus was a common forest element during Neogene (Miocene time) in Asia.