The function and morphology of plant leaves typically differ according to leaf habit (evergreen vs deciduous), and these differences have been thought to respond divergently to climatic conditions. While the variations in leaf margins with leaf habit and their respective correlation with climate have been investigated, limited investigation has been conducted on other leaf physiognomic characters. In the present study, we studied 2111 evergreen and 1001 deciduous native woody dicotyledons, investigating how the occurrences of 21 leaf physiognomic characters vary with leaf habit in humid regions of China. We then analysed these leaf characters of evergreen and deciduous species and climate correlations using canonical correspondence analysis based on 498 and 521 calibration datasets, respectively. Our results show that most of leaf physiognomic characteristics differed significant between evergreen and deciduous species in terms of the percentage values and the ordination diagrams. The leaf physiognomic distribution of both evergreen and deciduous species exhibited remarkable differences in response to climate. The lobed, small (nano- and microphyll), obtuse apex, reflex base, wide (length: width ratio <= 2:1) and ovate shape leaves predominated in deciduous species and occurred in colder and drier climates, while untoothed, large (noto- and mesophyll), reflex apex, acute base, narrow (L:W ratio = 2-4:1) and elliptic shape leaves predominated in evergreen species and occurred in warmer and wetter climates. This distribution pattern was primarily influenced by winter temperature and precipitation. The leaf physiognomic characteristics of evergreen and deciduous species display distinct responses to winter climatic variables across humid regions of China, revealing differences in environmental tolerance between the two leaf habits. This also suggests that the East Asian winter monsoon especially influences the leaf physiognomic characters of both evergreen and deciduous species in China. Furthermore, our findings suggest that in addition to leaf margins, leaf habit could confound correlations between other leaf physiognomic characters and climate, potentially affecting the accurate prediction of paleoclimate in China using multivariate leaf physiognomy approaches.

We sequenced the leaf and inflorescence transcriptomes of 10 Elsholtzia species to mine genes related to the volatile terpenoid metabolic pathway. A total of 184.68 GB data and 1,231,162,678 clean reads were obtained from 20 Elsholtzia samples, and 333,848 unigenes with an average length of at least 1440 bp were obtained by Trinity assembly. KEGG pathway analysis showed that there were three pathways related to volatile terpene metabolism: terpenoid backbone biosynthesis (No. ko00900), monoterpenoid biosynthesis (No. ko00902), and sesquiterpenoid and triterpenoid biosynthesis (No. ko00909), with 437, 125, and 121 related unigenes, respectively. The essential oil content and composition in 20 Elsholtzia samples were determined by gas chromatography-mass spectrometry. The results showed that there were obvious interspecific differences among the 10 Elsholtzia species, but there were no significant differences between the different tissues among species. The expression levels of seven candidate genes involved in volatile terpenoid biosynthesis in Elsholtzia were further analyzed by quantitative real-time PCR. The results showed that HMGS had the highest expression among all genes, followed by GGPS4. In addition, there was not a significant correlation between the seven genes and the components with high essential oil contents. Combined with the essential oil components detected in this study, the possible biosynthetic pathway of the characteristic components in Elsholtzia plants was speculated to be a metabolic pathway with geraniol as the starting point and elsholtzione as the end product. Phylogenetic analysis was conducted using the nucleotide sequences of the geranyl diphosphate synthase candidate genes, and the results showed that genes related to the volatile terpenoid biosynthetic pathway may be more suitable gene fragments for resolving the Elsholtzia phylogeny.

Background Wild edible plants (WEPs) are non-cultivated and non-domesticated plants used for food. WEPs provided food, nutrition, herbs and other plant products for people in underdeveloped areas, such as the Everest region, to maintain their daily lives. Chenthang Town is the only Sherpa ethnic township in Tibet, China. The core purpose of this research is to investigate, collect and record the WEPs and related local knowledge and functions within the Sherpa community. The ultimate goal is to answer the question of why Sherpa people choose these particular plants. Materials and methods The field study was carried out in the six Sherpa communities of Chenthang Township from September 2019 to August 2020. The WEPs and related local knowledge were collected through semistructured interviews and direct observations. The field work was performed with the assistance of local guides. During the field survey, we collected plant specimens based on the principle of one plant with one vernacular name. In this study, we utilised a use report (UR) and cultural importance index (CI) to evaluate the comprehensive utilization value of WEPs in the daily diet of Sherpa people. Results We interviewed 78 people individually who provided us with 1199 use reports. In total, we collected 84 WEPs belonging to 65 genera in 41 families. These species were identified as 78 distinct ethno-species by local people, and the vernacular name of each ethno-species was recorded. Then, these use reports were classified into six use categories. All these plants were native wild plants. In these plants, Arisaema utile, Sorbus cuspidata and Elaeagnus umbellata have been introduced into home gardens by local people. Following the description of the Sherpa people, we articulated a collection calendar for WEPs. The Sherpa collect WEPs throughout nearly the entire year, January and February being the exceptions. Conclusion The collection calendar of wild edible plants reflects the wisdom of the Sherpa in terms of survival. The Sherpa cleverly survive the food shortage periods by harnessing the phenology of different species. In general, WEPs can provide the Sherpa with seasonal carbohydrates, nutrition, healthcare supplements and other products and services necessary for survival, which is likely why the Sherpa choose these plants.

Background: Strobilanthes cusia (Nees) Kuntze is an important medicinal, edible, and indigoyielding plant species. It has been cultivated for centuries and it is often the only natural dye still used in many places of East and Southeast Asia. Although S. cisia is extensively cultivated and widely used, the ecological factors of its environmental demands are poorly understood. Moreover, with the increasing demand and growing habitat degradation, its wild populations are in sharp decline. It is therefore imperative to understand the socio-ecological interactions of this species regarding its climatic niche, ethnobotanical importance, and human relations in order to meet its demand. Methods: We first collected S. cusia occurrences from plant species databases, literatures and ethnobotanical surveys. 244 wild occurrences and 10 variables were used to predict its suitable habitats using the MaxEnt model. Furthermore, for a better understanding of socio-ecological interactions regarding its distribution and use, we also collected use reports and calculated the relative importance level (RIL). Results: Strobilanthes cusia is valued for many reasons, as it contains numerous health benefits as a medicinal plant and use in tea alongside its indigo dying and tattooing properties. Indigo dye, Southern Banlangen, and Indigo Naturalis are its most important usages. Its suitable habitats are chiefly located in Western and Central Himalayas, Southern China, and Southern Japan. The 'temperature seasonality (standard deviation x 100)' (bio4), the 'precipitation of coldest quarter' (bio19), and the human footprint index showed the strongest association with the relative contributions of 38.5%, 32.4%, and 9.1%, respectively.

Background Wild edible plants (WEPs), which are identified as non-cultivated and non-domesticated plants for food. WEPs provided food, nutrition, herbs and other plant products for people in underdeveloped areas, such as the Everest region, to maintain their daily lives. Chenthang Town is the only Sherpa ethnic township in China. The core purpose of this research is to investigate, collect, and record the WEPs and related local knowledge and functions in the Sherpa community. Looking forward to answering the ultimate question, why did Sherpa people choose these plants? Materials and methods The field study was carried out in the six Sherpa communities of Chenthang Township from September 2019 to August 2020. The WEPs and related local knowledge were collected by semi-structured interview and direct observation. And the field works were performed with the assistance of local guides. During the field survey, we collected plant specimens based on the principle of one plant with one vernacular name. In this study, we used use-report (UR) and cultural importance index (CI) to evaluate the comprehensive utilization value of WEPs in the daily diet of Sherpa people. Results We interviewed 78 people individually who provided us with 1,199 use-reports. In total, we collected 84 WEPs belonging to 62 genera in 40 families. These species were identified into 78 ethno-species by local people, and the vernacular name of each ethno-species was recorded. These use-reports were classified into 6 use-categories. All of these plants were native wild plants. In these plants, Arisaema utile, Sorbus cuspidat and Elaeagnus umbellate have been introduced into home gardens by local people. According to the description of the Sherpa people, we drew a collecting calendar of WEPs. The Sherpa collect WEPs almost throughout the year, except for January and February. Conclusion WEPs have made a huge contribution to the Sherpa dietary in supplementing Carbohydrate, nutrition, and healthcare during the seasonal food shortage. In general, the diversity and products and services of WEPs based on local knowledge enhance the resistance and resilience of local food supply system to treat food shortage which might be the answer to why the locals choose these plants.

Background Douyu Village, inhabited by the Lhoba people, is situated within the Eastern Himalayas, in southeastern Tibet, China. The village is located among high mountains and valleys, which feature complex terrain with cold and dry climates and distinctive vegetation types and species. The Lhoba people in this village are isolated from other groups in China. The Lhoba people have lived in this village since the 15th century and mainly depended on gathering, hunting, and swidden agriculture before the 1960s. Because they have a long history and live under extreme climatic, geographical, and ecological conditions, the Lhoba people in Douyu Village may have unique traditional knowledge about wild plants. Thus, this research aims to record the traditional botanical knowledge of the Lhoba people in Douyu. Methods An ethnobotanical study was conducted on the Lhoba people in Douyu Village in Longzi County, Tibet, China. Semi-structured interviews and group discussions with informed consent were used in the study. We interviewed 41 informants (14 key informants) between 18 and 75 years of age. All information was collected, organized, and compiled into "use reports" for quantitative analysis. The informant consensus factor (ICF) was used to determine the homogeneity of the informants' knowledge of medicinal plants, while the cultural importance index (CI) was used to estimate the cultural importance of shared species. Results A total of 91 wild species (90 vascular plants and 1 fungus) belonging to 71 genera and 39 families utilized by the Lhoba people in Douyu were documented. Of these species, Pimpinella xizangense and Wikstroemia lungtzeensis are endemic to Longzi County, while Sinopodophyllum hexandrum and Paeonia ludlowii are endangered species in China. All habitats, from the field vegetation at the valley bottoms to the alpine shrubland and meadows, were used for plant collection, and the numbers of species of plants collected from the various vegetation types (except for fields) decreased with increasing altitude. Our study found that 55 species are edible plants and fungi, 29 species are medicinal plants, and 38 species are used for other purposes. Medicinal plants are used for 11 categories of diseases, among which diseases of blood-forming organs (ICF = 0.96) and gastrointestinal diseases (ICF = 0.95) exhibited the highest ICF values. Based on the CI values, the most important plants in this study area are Berberis xanthophloea, B. kongboensis, Sinopodophyllum hexandrum, Vicatia thibetica, and Hippophae rhamnoides subsp. gyantsensis. Moreover, a comparison of the wild plants used by Lhoba ethnic groups in three counties in China showed significant differences among these regions. Conclusions Our study demonstrates that the wild plants utilized by the Lhoba people in Douyu Village are highly diverse, at 90 plant and one fungal species, which reflects not only the number of species but also their diversified functions. The extreme climatic, geographical, and ecological conditions of Douyu within the high mountains and valleys of the Eastern Himalayas potentially affect the Lhoba people's culture, including plant utilization practices, and contribute to the rich diversity of the wild plants used by the local people.

Understanding how geographical patterns of plant richness are established is a key scientific question in ecology and biogeography. Climate factors, such as environmental energy, water availability, and rainfall seasonality, have been widely proposed to account for geographical patterns of plant richness at large scales. Using a compiled distribution data set of 3166 native woody dicotyledons across 732 calibration grids at the county level in humid regions of China, we explored the geographical pattern of woody dicotyledon richness and its relationship to climatic variations, especially the Asian monsoonal climate. We found that species richness decreases with increasing latitude. Our study indicates that water availability (particularly mean annual precipitation, MAP) is the major abiotic factor in determining large-scale distribution patterns of species richness. Moreover, the seasonality of rainfall variables under the Asian monsoon climate largely contributes to species richness, because species richness correlates more significantly with precipitation during the three driest consecutive months (P3DRY) than precipitation during the three wettest consecutive months (P3WET). Therefore, we conclude that woody dicotyledon richness in humid regions of China is mainly affected by the Asian winter monsoon.

Ethnopharmacological relevance: The Lhoba people are a small, ancient, tribal ethnic group from the Himalayas and are located in the Tibet Autonomous Region of China. Medog County is rich in biocultural diversity. For a long time, Medog has been almost isolated from the outside world. The Lhoba people, who live in Medog, have maintained a relatively unique lifestyle and have accumulated rich traditional knowledge (TK), especially about medicinal and edible plants. Currently, there is very little documentation of the plants traditionally used by the local Lhoba communities. Aim of the study: Our investigation aimed to (i) document the species of medicinal and food plants used by the Lhoba people in Medog County, Tibet, China; (ii) screen the most important plant taxa for specific medicines, and identify the aliments treated to further contribute to drug and food supplement research; and (iii) examine whether the ethnobotanical knowledge of the Lhoba is similar among different tribes and discuss traditional uses in the health practices and livelihoods of the local communities. Methods: Ethnobotanical data were recorded through semi-structured interviews, guided field trips, and quantitative analysis. The informant consensus factor (FIC) was used as a quantitative index. Results: Ninety-one informants (61 men and 30 women) were interviewed. A total of 75 species, including 37 medicinal plants for 14 categories of diseases and 57 edible plants from six types of food, were recorded. Among the usage types of medicinal plants, the highest FIC values were recorded for antidotes (FIC = 0.98), anthelmintics (FIC = 0.98), and treatments of gastrointestinal problems (FIC = 0.93). The FIC values for different types of edible plants were very similar. The most frequently used medicinal and food plants in the studied communities are Zanthoxylum motuoense, Crassocephalum crepidioides, and Swertia nervosa. According to the comparative study, few differences in the use of wild plants were found. There appeared to be more overlapping species between two Lhoba tribes in Medog, named Mixingba and Miguba, with 46 (61%) common species, compared with the Bo'gaer tribe in Milin, which had only two (2.7%) overlapping species. This might be due to the different geographical environments, vegetation types, and different influences of other ethnic cultures. Conclusions: The Lhoba people in Medog County, Tibet, China, have rich TK about the uses of wild plants. However, the TK is seriously threatened due to environmental degradation and acculturation, and it showed signs of being forgotten and abandoned by the younger generation. Therefore, measures are urgently needed to document and protect the TIC of the uses of the wild plant resources; and (i) the most frequently used medicinal and/or edible plants; (ii) the plants used to treat the most commonly mentioned diseases; and (iii) the endemic species that are widely used in Medog, which should be assessed for their potential future as food supplements and therapeutic products.

In this paper, correlation between modern leaf physiognomy and climate in China are examined, to optimize the use of leaf characters as a palaeoclimate proxy. A large dataset was compiled, recording the distribution of leaf physiognomic characters among 3166 native dicot trees species across 732 calibration grids on a county level. Grids span a range of ecological environments (tropical rainforests to alpine shrubs) across humid areas. Thirteen climatic parameters were included for each grid and 22 leaf physiognomic characters were scored for each tree species. The correlation between leaf physiognomic characters and climatic parameters were calculated based on single linear regressions (SLR) and multiple linear regressions (MLR). Results indicate clear spatial distribution patterns, linked to latitude, exist for all leaf characters, with temperature (Coldest Month Mean Temperature, CMMT) and precipitation (Growing Season Precipitation, GSP) being the main climate controls. Moreover, because leaf characters are more closely correlated with Precipitation during the Three Wettest Consecutive Months (P3WET), rather than with Precipitation during the Three Driest Consecutive Months (P3DRY), seasonal variations in rainfall associated with the Asian Monsoon might especially influence leaf physiognomic characters. Closer correlations between leaf physiognomy and climate are seen using MLR compared with SLR; therefore Mean Annual Temperature (MAT) and Mean Annual Precipitation (MAP) based on MLR equations provide the most promising basis for palaeoclimate reconstructions in China.

Several conservation programs have been started for the critically endangered Sichou oak（Quercus sichourensis） since 2007.These programs include detailed field investigations,seedling cultivation and research on the fruit biology of the species.In this study,we first report on the five mature individual trees found in our 9-year field investigation.Thus far,a total of 10 mature individuals have been recorded.All Q.sichourensis trees are healthy and most produce healthy acorns.Acorns of Q.sichourensis are large with dry masses of 8.0-14.0 g.These acorns had high moisture contents at collection and died shortly after（7-28 d） when dried with silica gel.Characteristics of Q,sichourensis acorns varied between populations.Compared with the acorns from Funing,the acorns collected from Ceheng were bigger,more viable（germination percentage was up to 96%）,less sensitive to desiccation,and germinated faster.Q.sichourensis occurs in regions with a distinct 5-6 month dry season.Habitat degradation is largely responsible for the rareness of Quercus sichorensis,but desiccation sensitivity of the acorns may also limit the regeneration of the species and potentially lead to its continued rareness.As a species with extremely small populations（PSESP）,Q.sichourensis is facing high risk of extinction and should be defined as a Critically Endangered species in the global IUCN Red List.

Cedrelospermum (Ulmaceae) is an extinct genus with extensive fossil records in Europe and North America. However, no fossil of the genus has been reported from Asia. Here we describe Cedrelospermum asiaticum L.B. Jia, Y.J. Huang et Z.K. Zhou sp. nov. based on compressed fruits from the late Miocene of Yunnan, southwestern China. The fossil fruits are characterized by an ovate fruit body adjoined by double wings, with the veins on the primary wing converging toward a stigmatic area. According to the historical geographic distribution of the genus, we hypothesize that Cedrelospermum originated in North America where both single-winged and double-winged fruits were reported. The single-winged form subsequently spread into Europe via the North Atlantic land bridge and the double-winged form dispersed into Asia via the Bering land bridge. From the Eocene to Oligocene, a southward retreat of the genus distribution probably took place, which coincided with the global surface cooling initiated during the Eocene–Oligocene transition. The extinction of Cedrelospermum from Asia may be related to the intensification of the East Asian monsoon.

The family Orchidaceae is not only one of the most diverse families of flowering plants, but also one of the most endangered plant taxa. Therefore, understanding how its species richness varies along geographical and environmental gradients is essential for conservation efforts. However, such knowledge is rarely available, especially on a large scale. We used a database extracted from herbarium records to investigate the relationships between orchid species richness and elevation, and to examine how elevational diversity in Yunnan Province, China, might be explained by mid-domain effect (MDE), species-area relationship (SAR), water-energy dynamics (WED), Rapoport's Rule, and climatic variables. This particular location was selected because it is one of the primary centers of distribution for orchids. We recorded 691 species that span 127 genera and account for 88.59% of all confirmed orchid species in Yunnan. Species richness, estimated at 200-m intervals along a slope, was closely correlated with elevation, peaking at 1395 to 1723 m. The elevational pattern of orchid richness was considerably shaped by MDE, SAR, WED, and climate. Among those four predictors, climate was the strongest while MDE was the weakest for predicting the elevational pattern of orchid richness. Species richness showed parabolic responses to mean annual temperature (MAT) and mean annual precipitation (MAP), with maximum richness values recorded at 13.7 to 17.7°C for MAT and 1237 to 1414 mm for MAP. Rapoport's Rule also helped to explain the elevational pattern of species richness in Yunnan, but those influences were not entirely uniform across all methods. These results suggested that the elevational pattern of orchid species richness in Yunnan is collectively shaped by several mechanisms related to geometric constraints, size of the land area, and environments. Because of the dominant role of climate in determining orchid richness, our findings may contribute to a better understanding of the potential effects of climate change on orchid diversity, and the development of conservation strategies for orchids.

Cenozoic plant relicts are those groups that were once widespread in the Northern Hemisphere but are now restricted to some small isolated areas as a result of drastic climatic changes. They are good proxies to study how plants respond to climatic changes since their modern climatic requirements are known. Herein we look at the modern distribution of 65 palaeoendemic genera in China and compare it with the Chinese climatic pattern, in order to find a link between the plant distribution and climate. Central China and Taiwan Island are shown to be diversity centres of Cenozoic relict genera, consistent with the fact that these two regions have a shorter dry season with comparatively humid autumn and spring in China. Species distribution models indicate that the precipitation parameters are the most important variables to explain the distribution of relict genera. The Cenozoic wide-scale distribution of relict plants in the Northern Hemisphere is therefore considered to be linked to the widespread humid climate at that time, and the subsequent contraction of their distributional ranges was probably caused by the drying trend along with global cooling.

It is widely accepted that the late Pliocene spans a time with globally warmer conditions compared to today. Regional specifics in temperature patterns from this period, however, remain poorly known. In this study, we reconstruct quantitatively late Pliocene climates for eight sites at the southeastern border of the Qinghai-Tibet Plateau (SBTP), based on palaeobotanical data compiled from published sources using the Coexistence Approach (CoA), and analyze anomalies with respect to modern climates. The reconstructed temperatures indicate that in the late Pliocene, the northwestern part of the study area was cooler than its southern part. This spatial differentiation in temperature was largely due to differences in altitude: the northwest of the SBTP probably had higher altitudes than the south at that time. Mean annual temperatures (MATS) were around 1 degrees C higher than today, suggesting a cooling trend since the late Pliocene. Our data show that summer temperatures have declined significantly since the late Pliocene while winter temperatures have remained similar to those of the present, different from observations in other territories. The unexpected summer and winter temperature changes can be explained by the regional orogenic uplift plus the global cooling. The eastward extrusion of the Qinghai-Tibet Plateau might have blocked the southward cold high pressure of the winter monsoon and forced it to circumvent the eastern flank of the plateau, weakening its impact on the SBTP. The post-Pliocene mountain uplift increased the overall altitude of the region, which caused the temperature decline for both summer and winter. The reconstructed summer precipitation was lower while the winter precipitation was higher than today, suggesting a weaker monsoon climate during the late Pliocene. (C) 2015 Elsevier Ltd. All rights reserved.

Abstract. The Tropical Niche Conservatism Hypothesis (TCH) tries to explain the generally observed latitudinal gradient of increasing species diversity towards the tropics. To date, few studies have used phylogenetic approaches to assess its validity, even though such methods are especially suited to detect changes in niche structure. We test the TCH using modeled distributions of 1898 woody species in Yunnan Province (southwest China) in combination with a family level phylogeny. Unlike predicted, species richness and phylogenetic diversity did not show a latitudinal gradient, but identified two high diversity zones, one in Northwest and one in South Yunnan. Despite this, the underlying residual phylogenetic diversity showed a clear decline away from the tropics, while the species composition became progressingly more phylogenetically clustered towards the North. These latitudinal changes were strongly associated with more extreme temperature variability and declining precipitation and soil water availability, especially during the dry season. Our results suggests that the climatically more extreme conditions outside the tropics require adaptations for successful colonization, most likely related to the plant hydraulic system, that have been acquired by only a limited number of phylogenetically closely related plant lineages. We emphasize the importance of phylogenetic approaches for testing the TCH.

Leaf margin analysis (LMA) is an important method of estimating paleotemperatures from fossil leaf floras or modern floras. Although some calibration has been carried out based upon large-scale studies of modern forests, most of this research has been in North America and Europe, with relatively little calibration work in East Asia. In the present study, we used species range maps of 3116 native dicot trees of China to derive synthetic local floras for each county from the Chinese humid region, and compared the percentage of untoothed leaf margined species with several temperature and precipitation related parameters. The results confirm the generally strong relationship between the proportion of species with untoothed leaf margins and climatic parameters within China. Leaf habit (deciduous vs. evergreen) does not strongly affect this relationship. The transfer function obtained from China, while not identical, is similar to those obtained from other regions, and is affected by regional restrictions, such as complex topography and relic taxa. As such it clarifies the potential range of error inherent in the LMA method as applied to paleoclimate reconstruction. It is possible, however, that with the close similarity of the modern Chinese tree floras to Neogene floras in the Northern Hemisphere, the present estimate offers a better transfer function for reconstructing the Neogene paleoclimate in various regions without extremely cold conditions across the Northern Hemisphere.

A wide range of forests distributed across steep environmental gradients are found in Yunnan, southwest China. Climate change could profoundly change these forests by affecting species ranges. We produce predictions about species suitable habitat shifts and use these to (1) evaluate species range size change, loss and turn‐over under no‐ and full‐dispersal and nine climate change scenarios and (2) identify environmental variables responsible for current species richness and future local species losses.

The relationship between leaf physiognomy and precipitation has been explored worldwide in regions under different climate conditions.Unlike the linear relationship established between the percentage of woody dicot species with entire margins and mean annual temperature, precipitation has been reported to correlate to different leaf physiognomic characters depending on the region where the correlation is studied.To investigate if precipitation can be calculated from leaf physiognomic characters on the basis of regional sample sites, data from 50 mesic to humid forests in China were analyzed in this study.With data from Chinese forests, the leaf-area analysis based on linear regression between natural logarithms of leaf size and mean annual precipitation (MAP) shows no significant correlation.Both single and multiple linear regression analyses fail to confirm the correlation between leaf physiognomy and precipitation, which may result from the similarity of modern spatial distribution of temperature and precipitation in China.Our results show that, due to variations in climatic conditions among sampling regions, leaf physiognomic characters that correlate to precipitation are not consistent worldwide, and applications of models without considering regional constraints could mislead our understanding of palaeoclimate.Therefore, when choosing a leaf physiognomic model for palaeoclimate reconstructions, it is important to determine if the leaf physiognomy of the palaeoflora lies within the leaf physiognomic spectrum of the model used.

选取我国西南地区槭属(槭树科)的8个现生种,通过观察和测量馆藏标本的翅果形态,对比同一个种的翅果在不同地区的形态差异性,并通过主成分分析(PCO)检测翅果在种内的形态变异性,发现槭属的翅果形态具有明显的地区间差异性,这种差异性主要表现在总体形状和大小上,这可能与地区间不同的气候环境特征有关.通过对槭属翅果种内形态变异性和多样性的深入研究,为槭属翅果化石的属下鉴定提供一定依据,指出槭属翅果化石的属下鉴定应该考虑翅果形态种内变异性的特征,具有形态多样性的该属翅果化石可能属于一个种或更少的种.