The genus Mezoneuron Desf. (Caesalpinioideae, Fabaceae) comprises 23 extant species distributed throughout the Old World tropics and subtropics, yet its fossil record is scarce with finds restricted to Europe and North America. Here, we report a new Mezoneuron pod fossil from the lower Miocene Sanhaogou Formation of Jinggu Basin in Southwest China, representing the first fossil occurrence of this genus in Asia and the only one within its current distribution range. The fossil presents a vascularized wing along the placental suture and with poorly developed, irregular reticulate venation, which are typical pod characters in Mezoneuron. With detailed morphological observation and comparison, it is assigned as a new species, namely M. zhekunii Y.S. Zhao, L.B. Jia et T. Su sp. nov. Together with the historic and modern distribution of Mezoneuron and its relatives, we propose that Mezoneuron originated in the Northern Hemisphere no later than the middle Eocene. Mezoneuron attained relatively low latitudes in Asia no later than the early Miocene, with our fossil representing the lowest latitudinal record. The oblique and fine wrinkles of pod probably suggest a papery texture and low weight observed in mature pods of some extant Mezoneuron species, which favors wind dispersal.

Dalbergia is a pantropical genus of Fabaceae but has limited fossil records. This study introduces hitherto most diversified, well-preserved Dalbergia fossils and the earliest leaf mining damage traces on this genus from Yunnan, southwestern China. Modern Eurasian leaf miner collections and herbarium specimens were used for identification. After comparison, we proved ancient Yunnan to be a hotspot for Dalbergia, and their interactions with various arthropods (Lepidoptera and other insects) have been established since the late Paleogene. Because of the scarce validated worldwide Dalbergia fossils, our results are crucial for phylogeny calibrating and understanding the evolutionary history of analogous mining behavior observed from modern Dalbergia.

BACKGROUND:The "woody clade" in Saxifragales (WCS), encompassing four woody families (Altingiaceae, Cercidiphyllaceae, Daphniphyllaceae, and Hamamelidaceae), is a phylogenetically recalcitrant node in the angiosperm tree of life, as the interfamilial relationships of the WCS remain contentious. Based on a comprehensive sampling of WCS genera, this study aims to recover a robust maternal backbone phylogeny of the WCS by analyzing plastid genome (plastome) sequence data using Bayesian inference (BI), maximum likelihood (ML), and maximum parsimony (MP) methods, and to explore the possible causes of the phylogenetic recalcitrance with respect to deep relationships within the WCS, in combination with molecular and fossil evidence.RESULTS:Although the four WCS families were identically resolved as monophyletic, the MP analysis recovered different tree topologies for the relationships among Altingiaceae, Cercidiphyllaceae, and Daphniphyllaceae from the ML and BI phylogenies. The fossil-calibrated plastome phylogeny showed that the WCS underwent a rapid divergence of crown groups in the early Cretaceous (between 104.79 and 100.23 Ma), leading to the origin of the stem lineage ancestors of Altingiaceae, Cercidiphyllaceae, Daphniphyllaceae, and Hamamelidaceae within a very short time span (∼4.56 Ma). Compared with the tree topology recovered in a previous study based on nuclear genome data, cytonuclear discordance regarding the interfamilial relationships of the WCS was detected.CONCLUSIONS:Molecular and fossil evidence imply that the early divergence of the WCS might have experienced radiative diversification of crown groups, extensive extinctions at the genus and species levels around the Cretaceous/Paleocene boundary, and ancient hybridization. Such evolutionarily complex events may introduce biases in topological estimations within the WCS due to incomplete lineage sorting, cytonuclear discordance, and long-branch attraction, potentially impacting the accurate reconstruction of deep relationships.

Dalbergia is a pantropical genus of Fabaceae with a limited fossil records. In this study we describe diverse and well-preserved Dalbergia fossils distributed through Cenozoic (Eocene to Pliocene) strata in Yunnan Province, southwest China. Comparison with newly collected modern samples from Eurasian forests and herbarium specimens allows accurate identification of our fossil materials, and we demonstrate that Yunnan Province represents an hitherto unrecognised hotspot for the diversification of Dalbergia. Our findings also include evidence of the earliest known mining damage reported on Dalbergia leaflets, which sheds light on their interactions with various arthropods (Leucoptera and other insects) during the early Neogene. As such, our results improve knowledge of Dalbergia fossils in East Asia and are crucial for understanding the evolutionary history of analogous mining behavior observed from modern Dalbergia.

Surface uplift at the southeastern margin of the Tibetan Plateau has been widely studied, but more palaeoaltimetry data are required to better understand the elevation history of this geologically complex region. In this study, fossil leaves of Abies (Pinaceae), a cool-temperate element, recovered from the latest Miocene–Pliocene Yangyi Formation of the southern Baoshan Basin, were used as a proxy to estimate the local palaeoelevation. Based on the regional modern altitude range (2100–4280 m) of the genus as well as regional temperature discrepancy (1.5 °C) between the past and present, the palaeoelevation of the study area was calculated to be >2360 m above sea level as compared to 1760 m at present. Our result suggests that the southern Baoshan Basin experienced pronounced uplift prior to the time of fossil deposition, probably as a result of crustal shortening and thickening of the northern Baoshan Terrane during the Eocene–Oligocene. We infer that surface growth in areas south of the Dali Basin may have been greater than previously interpreted, and that a widespread plateau or plateau patches higher than 2000 m probably extended southwards into at least the Baoshan Basin by the latest Miocene–Pliocene. We also infer that the elevation of the southern Baoshan Basin has decreased by at least 690 m since then, in contrast to most other scenarios in which the elevation of the southeastern margin of the Tibetan Plateau has increased or remained close to modern levels since the late Miocene. The major cause of the inferred altitude decline is likely tectonic deformation. As a transtensional graben basin, the Baoshan Basin has experienced pull-apart and base-fall movement since the late Miocene, which would reduce the altitude of its southern part located on the hanging wall. Surface erosion associated with the increased summer rainfall might also have played a role especially in reducing the local relief, although its contribution can be limited. Our study provides one of the few palaeoelevation estimates from areas south of the Dali Basin and an example of past elevation loss at the southeastern margin of the Tibetan Plateau, thus shedding important light on the landscape evolution of this region.

Here, we infer the historical biogeography and evolutionary diversification of the genus Lilium. For this purpose, we used the complete plastomes of 64 currently accepted species in the genus Lilium (14 plastomes were newly sequenced) to recover the phylogenetic backbone of the genus and a time-calibrated phylogenetic framework to estimate biogeographical history scenarios and evolutionary diversification rates of Lilium. Our results suggest that ancient climatic changes and geological tectonic activities jointly shaped the distribution range and drove evolutionary radiation of Lilium, including the Middle Miocene Climate Optimum (MMCO), the late Miocene global cooling, as well as the successive uplift of the Qinghai-Tibet Plateau (QTP) and the strengthening of the monsoon climate in East Asia during the late Miocene and the Pliocene. This case study suggests that the unique geological and climatic events in the Neogene of East Asia, in particular the uplift of QTP and the enhancement of monsoonal climate, may have played an essential role in formation of uneven distribution of plant diversity in the Northern Hemisphere.

Whether East Asian relict plants have recently taken refuge in their extant ranges or have long been inhabitants in those areas remains uncertain due to insufficient fossil records. Here, we report well-preserved new fossil fruit valves of an East Asian relict genus, Craigia, from the late Eocene of Southwest China, in its extant geographic range. The front projection of these fruit valves has a vertical crease in the middle and pinnate veins, whereas their back projection possesses a stout vascular bundle in the middle separating two flask-shaped locules. Morphological comparisons suggest the placement of these fruit valves within the fossil species, C. oregonensis. Based on recent fossil records, Craigia possibly originated in the high latitudes of Northeast Asia during the Paleocene. It migrated to Southwest China by passing through Central Asia and Tibet when the climate in these areas was warm and wet during the early Paleogene. Our finding of Craigia fruit valves in Southwest China suggests that the genus arrived in and has inhabited its extant geographical range, at least since ∼34 million years ago (late Eocene).

Wildfire bears a close relationship with vegetation as its fuel source. The southeastern margin of the Tibetan Plateau witnesses frequent wildfires among various types of vegetation, whereas such wide interactions between wildfire and vegetation remain poorly studied from geological times. In this study, we reported a local fire using sedimentary macroscopic charcoals from the latest Miocene to early Pliocene of the Baoshan Basin in this region, and then inferred the local vegetation at the time of the fire event based chiefly on the coexistent fruit and seed fossil assemblage. Our taxonomic results show that the charcoal assemblage is probably dominated by broadleaved plants and the fruit and seed fossil assemblage is apparently dominated by Salix (Salicaceae) followed by Sambucus (Adoxaceae), suggesting a deciduous broadleaved forest in which the fire likely occurred. Under a seasonally dry climate associated with the Asian monsoon, this type of vegetation might be prone to natural fire, because in the wet rainy season the plants grew well to accumulate biofuel and in the dry season abundant ground litter resulting from leaf decay would be desiccated to become highly flammable. Due to the fire-tolerant habit of Salix as the dominant plant, the forest might be in return adapted to the fire event or even more fires that potentially followed. All these may suggest a close relationship between the fire event and the reconstructed vegetation. Our finding documents a new type of wildfire–vegetation interaction, namely the interaction between wildfire and deciduous broadleaved forest, from the geological past at the southeastern margin of the Tibetan Plateau. It therefore sheds new light on the wildfire history coupling vegetation change in the region.

Dipteronia, now endemic to East Asia, was widely distributed in North America during the Paleogene; however, its fossil records in Asia are scarce and none are of the Neogene. Here, we report the first Neogene Dipteronia samaras from South Korea. The more complete fossil records suggest that Dipteronia possibly originated in either Asia or North America and that its two known lineages have different geographical histories. The Dipteronia sinensis lineage was established in Asia and North America in the Paleocene and reached its maximum range in the Eocene, followed by stepwise range contraction and extirpation in North America, South Korea, and southwestern China, finally becoming endemic to central China. In contrast, the Dipteronia dyeriana lineage might have been restricted to southwestern China, where it originated, indicating historical confinement. The current restricted distribution of Dipteronia possibly resulted from its evolutionary deceleration in a constantly changing environment.

植物化石在青藏高原形成过程、植物系统演化和高原生物多样性格局演变的研究中, 发挥着不可替代的作用. 近十年来, 青藏高原新生代植物学研究取得重要进展, 主要包括: (1) 大量新类群被发现. 在西藏新生代植物记录中, 一共发表了63个新种, 其中45个是2010年以后发表的, 占全部新种的70%以上. 这些新种不少是其所在科、属在亚洲乃至全球最早的化石记录, 因此青藏高原是亚洲植物区系的重要源头. (2) 古近纪青藏高原是全球植物区系交流的十字路口, 是植物区系交汇的一个港湾. 目前的古植物地理学研究表明, 该地区植物区系成分的传播和交流, 有进入青藏、走出青藏、走出印度和进出非洲4种模式. (3) 植物化石见证了青藏高原差异隆升的历史. 古高程重建发现古近纪青藏高原中部存在东西向的亚热带中央谷地. 对西藏芒康不同层位植物组合的古高程研究表明, 这一地区在始新世-渐新世之交快速抬升了将近1000m, 达到现今高程; 结合其他古高程重建工作, 推断青藏高原东南缘(即横断山地区)在早渐新世就已经达到现代的高程, 而此时青藏高原中部仍存在着一个东西向的中央谷地. (4) 植被与地球环境协同演化. 青藏高原地区经历了热带、亚热带、温带、高寒区等不同气候类型的演替, 植被和植物多样性也随之改变, 体现了植被对青藏高原地形地貌演变的响应. (5) 先进方法和新思路逐渐应用于古植物学研究和古环境分析. 荧光显微技术、古气候模型等在古植物学研究中得到应用, 多学科交叉融合正在成为青藏高原新生代植物学研究的新趋势. 尽管青藏高原新生代植物学研究取得了长足进步, 但是该地区的化石记录仍旧缺乏, 今后需要继续开展古植物学的研究, 利用多学科手段深入解析青藏高原植物多样性演变历史与古环境变化过程.

The genus Mucuna Adans. (Papilionoideae, Fabaceae) contains approximately 105 extant species. It is widely distributed in pantropical areas, with its center of diversity located in Asia. Recent molecular phylogenetic analyses investigated the historical biogeography of the genus; however, a lack of fossil evidence has limited a fuller understanding of the genus. Here, we present the first macrofossil record of Mucuna in the form of pod, collected from late Miocene sediments of the Yen Bai Basin, northern Vietnam. This fossil specimen is characterized by linear-oblong, compressed, torulose, slightly curved pods containing at least three to five seeds, a pair of thickened marginal wings, and an apex with a cone-shaped beak. Detailed morphological observation indicates that these fossil pods belong to Mucuna, and are provisionally assigned to M. cf. birdwoodiana Tutcher. Our discovery supports the hypothesis that Mucuna originated in Asia; moreover, it implies that the genus has been present and has adapted to the humid tropical climate in northern Vietnam since at least the late Miocene.

云南地处青藏高原东南缘,生物多样性丰富,季风气候特征明显.新生代剧烈的构造活动形成了众多山间盆地,其间保存了大量精美的植物化石,是探讨新生代以来植被、植物多样性和地球环境演变的理想地区.但是长期以来,由于地层年代学证据的缺乏,这些新生代沉积盆地的地质年代还存在很大争议.本研究通过对滇东南地区富宁县普阳盆地的含煤地层开展深入的孢粉学研究,探讨盆地含煤地层年代及其古气候演化过程.剖面下部煤层孢粉组合以杉粉属(Taxodiaceaepollenites)为主,指示以杉科为主的湿润沼泽森林,冬春季相对湿润;剖面上部孢粉组合指示以常绿栎类为主的亚热带常绿-落叶阔叶混交林,生长山核桃粉属(Caryapollenites)、冬青粉属(Ilexpollenites)、胡桃粉属(Juglanspollenites)、枫香粉属(Liquidambarpollenites)等亚热带常见树种,气候温暖湿润,季节分明.结合新发现的哺乳动物化石证据和周边地区不同地质时代的孢粉组合,普阳盆地含煤地层的沉积时代应为晚始新世;同时,孢粉组合也表明滇东南地区植被现代化面貌至少在晚始新世就已经开始出现.

Plant fossils play an important role in understanding landscape evolution across the Tibetan Region, as well as plant diversity across wider eastern Asia. Within the last decade or so, paleobotanical investigations within the Tibet Region have led to a paradigm shift in our understanding of how the present plateau formed and how this affected the regional climate and biota. This is because: (1) Numerous new taxa have been reported. Of all the Cenozoic records of new plant fossil species reported from the Tibet (Xizang) Autonomous Region 45 out of 63 (70%) were documented after 2010. Among these, many represent the earliest records from Asia, or in some cases worldwide, at the genus or family level. (2) These fossils show that during the Paleogene, the region now occupied by the Tibetan Plateau was a globally significant floristic exchange hub. Based on paleobiogeographic studies, grounded by fossil evidence, there are four models of regional floristic migration and exchange, i.e., into Tibet, out of Tibet, out of India and into/out of Africa. (3) Plant fossils evidence the asynchronous formation histories for different parts of the Tibetan Plateau. During most of the Paleogene, there was a wide east-west trending valley with a subtropical climate in central Tibet bounded by high (>4 km) mountain systems, but that by the early Oligocene the modern high plateau had begun to form by the rise of the valley floor. Paleoelevation reconstructions using radiometrically-dated plant fossil assemblages in southeastern Tibet show that by the earliest Oligocene southeastern Tibet (including the Hengduan Mountains) had reached its present elevation. (4) The coevolution between vegetation, landform and paleoenvironment is evidenced by fossil records from what is now the central Tibetan Plateau. From the Paleocene to Pliocene, plant diversity transformed from that of tropical, to subtropical forests, through warm to cool temperate woodland and eventually to deciduous shrubland in response to landscape evolution from a seasonally humid lowland valley, to a high and dry plateau. (5) Advanced multidisciplinary technologies and novel ideas applied to paleobotanical material and paleoenvironmental reconstructions, e.g., fluorescence microscopy and paleoclimatic models, have been essential for interpreting Cenozoic floras on the Tibetan Region. However, despite significant progress investigating Cenozoic floras of the Tibetan Region, fossil records across this large region remain sparse, and for a better understanding of regional ecosystem dynamics and management more paleobotanical discoveries and multidisciplinary studies are required.

The Hengduan Mountains region (HMR) on the southeastern Tibetan Plateau, supports a high diversity of herbs, particularly in its subalpine to alpine ecosystems, due to high altitude and cool temperate climate. Current understanding on the formation of such herbaceous richness is based chiefly on molecular phylogenies; however, direct geological evidence is lacking because herbs are rarely preserved as macroscopic fossils. In this study, we present abundant fossil fruits and seeds of herbs from the late Pliocene Heqing Basin in the southern HMR. Our systematic analysis shows the presence of at least 18 species belonging to 11 genera, that is, Ranunculus, Corydalis, Rumex, Polygonum, Chenopodium, Stellaria, Fragaria, Astragalus, Aster, Carex, and Schoenoplectus, of which Polygonum is most abundant followed by Astragalus. This finding throws the first light from fossil evidence on the rise of herbaceous diversity in the region. We interpret the local assembly of these herbs as resulting from rapid pre-Pliocene species diversifications of many herbaceous groups in the HMR. As nowadays most of these herbs grow primarily in meadows and a few occur as subaquatic plants, we suggest an open meadow hosting some scattered shrubs in the vicinity of a vegetated wetland in the Heqing Basin during the late Pliocene. This provides the first direct evidence of past treeless open vegetation within the HMR and thus improves our knowledge of vegetation evolution in the region. We suggest that the uplift-induced climate cooling and monsoon-associated precipitation seasonality are potentially the key driving forces for the opening of meadow vegetation in the HMR.

Extant Bauhinia (Leguminosae) is a genus of 300 species of trees, shrubs, and lianas, widely distributed in pantropical areas, but its diversification history in southeastern Asia, one of its centers of highest diversity, remains unclear. We report new fossils of three Bauhinia species with cuticular preservation from the Paleogene of Puyang Basin, southwestern China. Our finding likely extends the emergence of Bauhinia in Asia to the late Eocene. Together with previously reported fossil records, we show that the diversification of Bauhina in Asia and the phenomenon of a small region harboring multiple Bauhinia species in southwestern China could be traced back to the Paleogene.

AbstractBackgroundLilium(Liliaceae) is an economically important genus with great medicinal, ornamental, and edible values, however evolutionary history of the genus remains poorly understood due to the lack of robust phylogeny. Based on a large plastome data set, this study aims to recover a robust backbone phylogeny of the genus to infer its historical biogeography and evolutionary diversification. Results Complete plastomes representing 50 currently accepted species in the genusLiliumwere sampled for phylogenetic analysis, among which, plastomes representing 14 species were newly sequenced in this study. Under time-calibrated phylogenetic framework, biogeographic scenarios and evolutionary diversification ofLiliumwere explored. Phylogenetic analysis recovered a backbone phylogeny ofLilium, in which most nodes were fully supported; however, failed to resolve all intrageneric sections as monophyletic. Ancestral area reconstruction proposed that the ancestor ofLiliummight widely distribute throughout the temperate regions of the Northern Hemisphere, and has experienced multiple dispersal, extinction, and vicariance events during the evolutionary course. The rate of species diversification has sharply accelerated since the late Miocene (ca.9 Ma) and kept increasing in the Pliocene and Pleistocene. Conclusions The results suggest that ancient climatic changes and geological tectonic activities, such as the Middle Miocene Climate Optimum (MMCO), the late Miocene global cooling, as well as the successive uplift of the Qinghai-Tibetan Plateau (QTP) and the enhancement of monsoonal climate in East Asia during the late Miocene and the Pliocene, jointly shaped the distribution range and drove evolutionary radiation ofLilium. Resulted from radiative divergence and distant dispersal events, the genus may have experienced incomplete lineage sorting (ILS) and morphological convergence. The uplift of QTP and enhancement of monsoonal climate dramatically triggered radiative divergence of species, accounting for the higherLiliumspecies diversity in East Asia than in Central Asia, Europe, and North America. The findings shed light on the crucial role of the unique Neogene geological and climatic events in East Asia, such as the uplift of QTP and the establishment of monsoonal climate, in shaping the uneven distribution of plant diversity in the Northern Hemisphere.

Sambucus L. (Adoxaceae) has a rich fossil record with a major concentration in Europe and North Asia but a scarcity in relatively low latitudes of the Northern Hemisphere. Herein, we report fossil endocarps of the genus from the late Pliocene Heqing Basin of northwestern Yunnan, South China, which are assigned to two species, namely S. alveolatisemina and S. heqingensis Huang et Zhou sp. nov. Sambucus alveolatisemina has been formerly described from the similar geological horizon of the nearby Lanping Basin in northwestern Yunnan and possibly represents the fossil equivalent of S. adnata, an extant species commonly seen in this and neighboring regions. Sambucus heqingensis is newly erected due to its exceptionally slender endocarp shape together with the irregularly ridged endocarp surface and straight lateral margins. Our fossil discovery, in combination with the two fossil taxa from the late Pliocene Lanping Basin, suggests that the diversity of Sambucus might have risen in South China by the late Pliocene. We conclude that, as compared to Europe and North Asia, the distribution and diversification of the genus in South China with much lower latitudes is likely to be a recent event. This can be properly explained by the fact that Sambucus is generally a temperate element while the climate in South China in prior to the Pliocene might be too warm for its inhabitation. We propose a hypothesis that the colonization and diversification of the genus in other low-latitude regions of the Northern Hemisphere might have been similarly late in time.

Recent paleobotanical investigations in Vietnam provide a good opportunity to improve our understanding of the biodiversity and paleoclimatic conditions in the geological past of Southeast Asia. Palms (Arecaceae) are a diverse family of typical thermophilous plants with a relatively low tolerance for freezing. In this study, we describe well-preserved fossil palm leaves from the Oligocene Dong Ho Formation of Hoanh Bo Basin, northern Vietnam. Characters of the fossil leaves, such as a fan-shaped costapalmate lamina, an unarmed petiole, a costa slightly enlarged at the base that then tapers distally into the blade, and well-preserved amphistomatic leaves with cuticles, suggest that they represent a new fossil species, which we herein designate Sabalites colaniae A. Song, T. Su, T. V. Do et Z.K. Zhou sp. nov. Together with other paleontological and palaeoclimatic evidence, we conclude that a warm climate prevailed in northern Vietnam and nearby areas during the Oligocene.

Aims: Due to complex geomorphology and diverse landscapes, the southern Hengduan Mountains region is home to highly diverse vegetation.The evolution and formation of such diversity is an interesting topic in the fields of botany and ecology, and plant fossils are an important proxy for researching this question.Method: In this study, we integrated published sources of nine fossil floras from the Pliocene of the southern Hengduan Mountains region.We first inferred the vegetation types of these fossil floras on the basis of their taxonomic compositions and dominant elements, and then depicted the diversity and spatial distribution of vegetation in the regionduring the Pliocene.We also correlated the rise of vegetation diversity and the formation of vegetation distribution to major environmental changes in the southern Hengduan Mountains region.Results: Our synthesis indicates that the southern Hengduan Mountain region already held a variety of vegetation types during the Pliocene, including subtropical evergreen broadleaved forest, subtropical deciduous broadleaved forest, sclerophyllous evergreen broadleaved forest, mixed coniferous broadleaved forest and shrubby meadow.The vegetation tended to have a warm affinity in the south and a cool-temperate affinity in the north, demonstrating altitudinal gradients with latitude at that time.Moreover, vegetation types are shown to be stratified at some localities, suggesting altitudinal gradients at local scales that are likely associated with the occurrence of high mountains.These are highly similar to the modern patterns of vegetation diversity and distribution in this region. Conclusion:Our study concludes that the modern diversity and distribution of vegetation in the southern Hengduan Mountain region was established no later than the Pliocene.However, more plant fossils from deeper times are needed to verify if the current vegetation was formed at an earlier geological age.

The fossil record evidences an old origin and diversification of Malvaceae in the Northern Hemisphere. The central Tibetan Plateau was at a low elevation with a monsoon influence during the Eocene, allowing the development of a subtropical flora containing Malvaceae. The taxonomic study of fossils from the Eocene of what is now the Tibetan Plateau is still ongoing. Malvaceae fossils from the Eocene Jianglang flora, are attributed to sub-families Tilioideae and Sterculioideae, and are compared with modern species. A new specimen of Firmiana is described based on a fruit valve with a pinnate venation, the secondary veins starting at the ventral suture and reaching the midvein, and the seeds attached at the proximal part of the ventral suture. This specimen represents the earliest known occurrence of the genus. A new occurrence of Craigia is also reported based on detached membranous valves of a fruit capsule with a prominent fusiform locular area and radiating venation. Based on the fossil record of Firmiana and its modern distribution, we infer that the genus may have originated in East Asia and subsequently diversified in South China and Southeast Asia. The new occurrence of Craigia indicates that the genus was distributed in humid areas in South, Southwest and North China during the Eocene. Both fossil records evidence the important role that the Tibetan region played in the diversification of plants in East and Southeast Asia.