Leaf Form Research Articles

BRYOCRUMIA VIVICOLOR, A RHEOPHYTIC, HYPNACEOUS MOSS, NEW TO THE WESTERN HIMALAYAS, INDIA

The Indian Himalayan sector is well known to support the diversified bryophyte species and communities due to varied phytoclimatical conditions met within different dissected topographical zones. Many potential wilderness areas are still waiting to be explored in terms of their exuberant bryodiversity. During a bryoexploratory survey of an unexplored high-altitude area in the Garhwal Himalayan region, we came across an interesting rheophytic moss Bryocrumia L. E. Anderson. The genus Bryocrumia is represented in India by two species, viz. B. vivicolor (Broth. et Dixon) W. R. Buck and B. malabarica Manju, Prajitha, Prakashkumar et W. Z. Ma. Both of these pleurocarpous species are known to be confined in the southern part of the country. From the Indian Himalayan sector, this moss genus has never been documented earlier. Recently, B. vivicolor has been reported for the first time from the Tungnath area (2,100–3,000 m above sea level) in the Garhwal region of Uttarakhand state as a new addition to the Western Himalayan moss flora, indicating its new distributional range. This hypnaceous moss was found colonising the slopy, wet, submerged rock surfaces along small streams and seepages in mixed oak forests on way to Tungnath. The key characteristics include its rheophilic habit, stem lacking central strand, variable leaf forms, indistinct double costa and round to obtuse leaf apex with prorate tip cells. The present paper provides taxonomic details of this rare moss, representing its wide geographical distribution in India.

Fossil leaves of Cenomanian basal angiosperms from the Peruc-Korycany Formation, Czechia, central Europe

Two leaf forms are described from the Cenomanian, Late Cretaceous of the Peruc-Korycany Formation in the Bohemian Cretaceous Basin in Central Europe. A new foliage genus and species Ascarinophyllum pecinovense Čepičková et J. Kvaček, gen. et sp. nov. is characterised by serrate margins with rounded chloranthoid teeth bearing a papilla. The leaf is hypostomatic, coriaceous, with resin bodies in the mesophyll. Its venation is festooned semicraspedodromous, with a robust midvein. On the abaxial cuticle, it shows laterocytic/laterocyclocytic, stephanocytic-bicyclic, amphibrachyparacytic, and less frequently brachyparacytic and holoparacytic stomata, showing sometimes T-shaped thickenings of the internal cuticle at the poles. The abaxial cuticle bears external striations; stomata are surrounded by stomatal rims. The leaf is compared to similar Early and Late Cretaceous angiosperm foliage, and to foliage of extant basal angiosperms. Cuticle analysis shows similarities in stomatal construction and external striations of the abaxial cuticle with fossil leaves of Mesodescolea plicata and extant Chloranthaceae.Todziaphyllum saportanum (Velen.) Čepičková et J.Kvaček comb.nov. is revised and its diagnosis is emended. T. saportanum leaf is characterised by serrate margins and semicraspedodromous venation. It is compared to morphologically similar Cretaceous angiosperm foliage, including Ascarinophyllum pecinovense. It is particularly similar to the recently defined fossil leaf Todziaphyllum elongatum, interpreted as having chloranthaceous affinity.

Structural, chemical and osteogenic properties of GNS reinforced fluorine-doped strontiumapatite coatings on AZ31 Mg alloys for potential biomedical applications

Different ion-doped composite coatings, especially graphene and fluorine-substituted apatite coatings, are intensely interested in surface modifications of different metallic implants for medical applications due to their excellent biological and chemical properties. However, their use in clinical applications in metallic implant materials is limited due to unsuitable biomechanical properties, low corrosion resistance, insufficient osteoinductivity, and bioactivity capacities. In this study, Graphene Nanosheet (GNS) and F-substituted SrAp (SrFAp/GNS) composite coatings were deposited on AZ31 magnesium substrate by hydrothermal method, and the effects of different GNS additives on SrFAp composite were reported for the first time. Morphological investigations showed crystals of SrFAp structures of GNS to grow in a needle-like structure and transform into a bone-like nano-needle structure. In addition, these structures began to transform into a more porous leaf form in the simulated body fluid. GNS layers also improved the surface properties and cell adhesion ability by developing a porous and rough coating morphology. With the GNS additive, the wettability properties of the composite coating were also significantly increased. In addition, the corrosion resistance of the examined coatings was significantly improved with the increasing GNS ratio. Co-doping of F and GNS in SrFAp/GNS coatings also improves the cytocompatibility of the SrAp construct. SrFAp/GNS composites significantly promote cell adhesion and proliferation and do not show any adverse toxic behavior. Therefore, SrFAp/GNS coated AZ31 Mg alloys, with their combination of high cytocompatibility, good mechanical properties, and superior corrosion resistance compared to Mg alloys, have shown promising results for clinical implant applications.

From genes to shape in leaf development and evolution

Plant leaves display tremendous variation in shape. Here, we discuss how information obtained from genetics, live imaging and computational modeling has helped conceptualize the ways in which gene activity is translated into different leaf shapes. In this framework, the action of genes on leaf form can be captured as the sum of their effects on the amount, duration, and direction of cellular growth, which together produce leaf geometry. We use three different examples to illustrate this point. First, the emergence of complex versus simple leaves in eudicots, which arises from differences in organ-wide growth duration as well as local growth repression at the leaf margin. Second, the development of strap-shaped grass leaves with a broad sheathing base versus the typical eudicot leaves with a narrow petiole, where these features of grass leaves emerged through lateral expansion of the zone of leaf progenitor cells, coupled with later remodeling of growth of early domains of the leaf blade. Third, the formation of insect traps on carnivorous plants that arose through constrained directional growth that produced a 3D deformation. In all the above examples, changes in gene expression of different classes of homeobox genes have contributed to the altered growth patterns underlying these different aspects of leaf shape diversity.

Revision of the Species Bauhinia bulgarica Kitan. fil. (Fabaceae) Known from the Bulgarian Upper Miocene-Lower Pliocene

A revision of the species Bauhinia bulgarica, which was found in the fossil macroflora of Garmen (SW Bulgaria), is presented. The fossil material originates from sediments dated as Late Miocene-Early Pliocene. The new taxonomic solution is Smilax excelsa L. foss. It is accepted on the basis of the close morphological structure of the fossil leaf imprint and the leaf forms of the recent Smilax excelsa L. (Smilacaceae), which is widespread in the SE Balkan Peninsula and SW Asia.

Clarification of the taxonomic and nomenclatural confusion about Arnica japonica L. f. and A. japonica Thunb. (Asteraceae: Senecioneae)

Arnica japonica L. f. and A. japonica Thunb. have long been controversial about their identities and nomenclature, largely due to the mysterious type material of Arnica japonica L. f. We locate the original material of Arnica japonica L. f., viz., LINN-HS 1322.1, and clarify the misleading description about its leaf form. Arnica japonica L. f. is revealed to be conspecific with A. japonica Thunb. Taxonomic and nomenclatural changes are made accordingly for these two names, and for Gynura japonica and Syneilesis palmata, another two names also involved in this issue. A second-step lectotype of Arnica japonica Thunb. is designated because of the taxonomically mixed material of the original lectotype.

Leaf Cell Morphology Alternation in Response to Environmental Signals in Rorippa aquatica.

Heterophylly, the phenomenon by which plants alter leaf forms to adapt to surrounding conditions, is apparent in amphibious plant species. In response to submergence, they emerge leaves with narrower blade areas. The pathway that receives the submergence signals and the mechanism regulating leaf form via cell proliferation and/or expansion systems have not yet been fully identified yet. Our anatomical study of Rorippa aquatica, an amphibious plant that exhibits heterophylly in response to various signals, showed that leaf thickness increased upon submergence; this was caused by the expansion of mesophyll cell size. Additionally, these submergence effects were inhibited under blue-light conditions. The ANGUSTIFOLIA3 (AN3)/GROWTH-REGULATING FACTOR (GRF) pathway regulating cell proliferation and cell expansion was downregulated in response to submergence; and the response was blocked under the blue-light conditions. These results suggest that submergence and light quality determine leaf cell morphology via the AN3/GRF pathway.

Patterns of compound-leaf form and deciduous-leaf habit across forests in China: Their association and key climatic factors

Leaf form (compound vs. simple) and habit (evergreen vs. deciduous) are key functional traits of trees to adapt to various climates and are vital in determining plant response to climate change. However, their association and climatic determinants remain uncertain, especially in East Asian forests in the largest monsoon region on earth. To fill these knowledge gaps, we compiled a dataset comprising 42 intact forests and over 2200 angiosperm tree species across China (spanning 30 latitudes and 47 longitudes). The geographical and climatic patterns of leaf form and habit were analyzed. The association between compound leaf and deciduousness was tested for tropical, subtropical and temperate climatic zones. We found that both the percentage of compound leaf (CT%) and deciduous tree species (DT%) increased with latitude and decreased with mean annual precipitation (MAP). For all forests, DT% was negatively related to mean annual temperature (MAT), whereas CT% was not. Nevertheless, both DT% and CT% increased with increasing MAT in the tropics, possibly owing to the high vapor pressure deficits (VPD) and canopy water deficits associated with high temperatures. A positive linear relationship between CT% and DT% was found across all forests and within different climatic zones except for temperate, and the intercept of the regression line was significantly higher in the tropics than in the subtropics. Overall, as supported by principal component analysis, deciduousness was negatively associated with both temperature and precipitation, while CT negatively with precipitation only across zones and positively with temperature in the tropics. Different relationships in different climatic zones suggest potentially different selective forces. Our findings provide novel insights into the linkage between leaf form and habit, as well as how climate shapes the landscape of broadleaf forests, which has important implications regarding the response of forest composition to climate change.

Replicated radiation of a plant clade along a cloud forest archipelago.

Replicated radiations, in which sets of similar forms evolve repeatedly within different regions, can provide powerful insights into parallel evolution and the assembly of functional diversity within communities. Several cases have been described in animals, but in plants we lack well-documented cases of replicated radiation that combine comprehensive phylogenetic and biogeographic analyses, the delimitation of geographic areas within which a set of 'ecomorphs' evolved independently and the identification of potential underlying mechanisms. Here we document the repeated evolution of a set of leaf ecomorphs in a group of neotropical plants. The Oreinotinus lineage within the angiosperm clade Viburnum spread from Mexico to Argentina through disjunct cloud forest environments. In 9 of 11 areas of endemism, species with similar sets of leaf forms evolved in parallel. We reject gene-flow-mediated evolution of similar leaves and show, instead, that species with disparate leaf forms differ in their climatic niches, supporting ecological adaptation as the driver of parallelism. Our identification of a case of replicated radiation in plants sets the stage for comparative analyses of such phenomena across the tree of life.

Geometric Morphometrics use in the examination of subgenus Quercus leaf shape variation in Algeria

Abstract The latest findings on the taxonomic review of Quercus faginea Lam. complex using ‘traditional morphometrics’, demonstrating that the species is represented in Algeria by both Q. faginea and Q. canariensis Willd. Significant variations of the leaf form were also discernible among both species. In this study, the landmark-based geometric morphometrics analysis was used to assess the shape variation of the leaves found on oak stands. 2,600 leaves per 13 stands were collected and scanned, and then using Tps range and MorphoJ software, 11 landmarks—that represent the leaf morphological features—were recorded on leaf images. Shape components and non-forms variations were obtained through a full Procrustes fit followed by creating a leaf-superimposed configuration. Principal component analysis, canonical variate analysis, and discriminate analysis were used to statistically evaluate the leaf shape variability. The results revealed no clear distinction between the two species based on leaf shape. Climate change and environmental factors also appear to have possibly caused a divergent morphological evolution; a reduced leaf size with enduring indumentum—among other Q. faginea traits—could be an efficient mean of adapting to Mediterranean xeric conditions.

The Historical Complexity of Tree Height Growth Dynamic Associated with Climate Change in Western North America

The effect of climate on tree growth has received increased interest in the context of climate change. However, most studies have been limited geographically and with respect to species. Here, sixteen tree species of western North America were used to investigate the response of trees to climate change. Forest inventory data from 36,944 stands established between 1600 and 1968 throughout western North America were summarized. The height growth (top height at a breast-height age of 50 years) of healthy dominant and co-dominant trees was related to annual and summer temperatures, the annual and summer Palmer Drought Severity Indexes (PDSIs), and the tree establishment date (ED). Climate-induced height growth patterns were then tested to determine links to the spatial environment (geographic locations and soil properties), the species’ range (coastal, interior, or both), and traits (shade tolerance and leaf form). Analysis was performed using a linear mixed model (total species) and a general linear model (species scale). Climate change was globally beneficial, except for Alaska yellow-cedar (Chamaecyparis nootkatensis (D. Don) Spach), and growth patterns were magnified for coastal-ranged, high-shade-tolerant, and broadleaf species, and mostly at the northernmost extents of these species’ ranges. Nevertheless, growth patterns were more complex with respect to soil properties. A growth decline for some species was observed at higher latitudes and elevations and was possibly related to increased cloudiness, precipitation, or drought (in interior areas). These results highlight the spatio-temporal complexity of the growth response to recent global climate change.

Molecular mechanisms underlying leaf development, morphological diversification, and beyond.

The basic mechanisms of leaf development have been revealed through a combination of genetics and intense analyses in select model species. The genetic basis for diversity in leaf morphology seen in nature is also being unraveled through recent advances in techniques and technologies related to genomics and transcriptomics, which have had a major impact on these comparative studies. However, this has led to the emergence of new unresolved questions about the mechanisms that generate the diversity of leaf form. Here, we provide a review of the current knowledge of the fundamental molecular genetic mechanisms underlying leaf development with an emphasis on natural variation and conserved gene regulatory networks involved in leaf development. Beyond that, we discuss open questions/enigmas in the area of leaf development, how recent technologies can best be deployed to generate a unified understanding of leaf diversity and its evolution, and what untapped fields lie ahead.

Interspecific morphological variation in Juglandoideae resting bud organization: a winter's tale?

Dormant resting buds are frequently regarded as static units, with protective cataphylls on the outside and embryonic foliage leaves on the inside. How the presence of cataphylls influences the dynamic, cyclical, annually repeating sequence of leaf forms that a resting bud gives rise to has rarely been interrogated. To examine the connection between dormant structure and growing-season development, we compare the complete seasonal heteroblastic sequence of leaf forms of six species of temperate Juglandaceae with distinctly different vegetative resting bud structures. These include buds with cataphylls; buds without cataphylls; and buds with caducous cataphylls that are lost before the onset of winter. In a common garden setting over a 7-month growing season, the dimensions of 2249 individual vegetative metamers were tracked from first exposure to abscission along the shoots of saplings and mature trees. The timing of metamer initiation within terminal buds was investigated using micro-CT scanning. Character state transitions of resting bud types were estimated using a phylogenetic tree of Juglandaceae. The presence of cataphylls within a heteroblastic sequence is associated with a single cohort of foliage leaves that flush and abscise synchronously. This growing pattern is highly determinate, with next year's terminal-bud cataphylls already initiated before spring leaf out. In contrast, in sequences without cataphylls, shorter-lived foliage leaves appear and abscise in a staggered fashion. Despite these differences in leaf demography, all examined heteroblastic sequences produce a series of small, caducous leaf forms that precede terminal bud set. The ubiquity of caducous leaf forms in Juglandoideae may point to the importance of shoot tip protection far beyond the dormant season. In addition, the presence or absence of cataphylls in resting buds is indicative of distinct shoot ontogenetic patterns, and functional strategies, in summer.

Lower Gondwana megaflora, palynoflora, and biomarkers from Jagannath Colliery, Talcher Basin, Odisha, India, and its biostratigraphic significance

The study of megafossils, palynomorphs, and biomarkers has been carried out from a fossiliferous section of Jagannath Colliery, Talcher Basin, Odisha, India. The megafloral assemblage recovered from the carbonaceous shale bed of the investigated section comprises 15Glossopterisspecies (leaf form),Vertebraria indica(root form), and stem cast of the order Glossopteridales. The megafloral assemblage and lithology (grey shale, carbonaceous shale, sandy shale, and coal seams) of the litho‐column suggest that the sediments belong to the Barakar Formation (Artinskian‐Kungurian age). Palynoflora recovered from the section is dominated byStriatopodocarpitesspp. (35–44%) and subdominated byFaunipollenitesspp. (29–35%) along with a good percentage ofDensipollenitesspp. Stratigraphically significant taxa of this palynoassemblage show its affinity toward the late Permian (Wuchiapingian‐Changhsingian) palynoflora which is geologically mapped as Barakar Formation of early Permian (Artinskian‐Kungurian) age. As a result, to clearly delimit the distribution of different lower Gondwana strata in this area, more precise palynological sampling and extensive geological mapping should be undertaken. The dominant occurrence of short‐chainn‐alkanes in the samples suggests the abundance of algal and microbial sources that are deposited in moderate water level conditions in the basin. Pristane/phytane ratio suggests oxic settings while the hopane distribution in the studied samples suggests significant bacterial degradation of the peat biomass in the depositional milieu.

Cytotoxic, apoptotic activities and chemical profiling of dimorphic forms of Egyptian halophyte Cakile maritima scop.

Cakile maritima ssp. aegyptiaca (Wild.) Nyman is growing with dimorphic leaf forms (entire or pinnatifid lamina) along the Mediterranean coast of Egypt. The cytotoxic activities of dried shoot systems of the two morphological forms were evaluated by testing and comparing the effects of ethanolic and aqueous extracts on the viability of five human cell lines. GC-MS analysis was performed to identify the bioactive and anticancer compounds present in the most active extracts. MTT assay indicated that both aqueous and ethanolic extracts have selective cytotoxic activities against cancer cell lines with no inhibitory activities against normal Wi38 or Vero cell lines. The underlying mechanism of cytotoxicity involved the induction of G2/M phase arrest in targeted cells MCF-7 and HCT-116 associated with inducing apoptosis in both cell lines, as indicated by Annexin-V assay. Apoptosis investigation in MCF-7 and HCT-116 cells treated with ethanolic extracts, was further investigated through RT-PCR, which exhibited elevation of proapoptotic genes of P53, BAX, Capase-3,6,7,8,9, and downregulation of antiapoptotic gene (BCL-2) upon treatment. The GC-MS analysis of ethanolic extracts of pinnatifid and entire forms revealed the existence of 18 and 13 compounds, respectively, with eleven compounds that were detected in pinnatifid form only and seven compounds were identified exclusively in the entire form. Molecular Docking study revealed that the identified compounds exhibited good binding affinity towards BCL-2 inhibition, and this agreed with the suggested apoptotic mechanism. To the best of authors’ knowledge, this is the first scientific evidence underline the variability in the chemical composition associated with variable anticancer activities of dimorphic forms of C. maritima. Communicated by Ramaswamy H. Sarma

Species Delimitation of Asteropyrum (Ranunculaceae) Based on Morphological, Molecular, and Ecological Variation.

Objectively evaluating different lines of evidence within a formalized framework is the most efficient and theoretically grounded approach for defining robust species hypotheses. Asteropyrum Drumm. et Hutch. is a small genus of perennial herb containing two species, A. cavaleriei and A. peltatum. The distinction of these two species mainly lies in the shape and size of leaf blades. However, these characters have been considered labile and could not differentiate the two species reliably. In this study, we investigated the variation of the leaf blades of 28 populations across the whole range of Asteropyrum using the landmark-based geometric morphometrics (GMM), sought genetic gaps within this genus using DNA barcoding, phylogenetic reconstruction and population genetic methods, and compared the predicted ecological niches of the two species. The results showed that the leaf form (shape and size) was overlapped between the two species; barcode gap was not detected within the genus Asteropyrum; and little ecological and geographical differentiation was found between the two taxa. Two genetic clusters detected by population genetic analysis did not match the two morphospecies. The results suggest that there are no distinct boundaries between the two species of Asteropyrum in terms of morphology, genetics and ecology and this present classification should be abandoned. We anticipate that range-wide population genomic studies would properly delineate the species boundaries and help to understand the evolution and speciation within Asteropyrum.

Leaf form diversification in an ornamental heirloom tomato results from alterations in two different HOMEOBOX genes

Domesticated plants display diverse phenotypic traits. However, the influence of breeding effort on this phenotypic diversity remains unknown. Here, we demonstrate that a single nucleotide deletion in the homeobox motif of BIPINNATA, a BEL-LIKE HOMEODOMAIN gene, led to a highly complex leaf phenotype in an heirloom tomato (Solanum lycopersicum), Silvery Fir Tree (SiFT), which is used as a landscaping and ornamental plant. A comparative gene network analysis revealed that repression of SOLANIFOLIA, the ortholog of WUSCHEL RELATED HOMEOBOX 1, caused the narrow leaflet phenotype seen in SiFT. Comparative genomics indicated that the bip mutation in SiFT likely arose de novo and is unique to SiFT and not introgressed from other tomato genomes. These results provide new insights into the natural variation in phenotypic traits introduced into crops during improvement processes after domestication and establish homeobox genes as evolutionary hotspots.

Promoting a better understanding of green infrastructure in urban planning to reduce air pollution exposure

BACKGROUND AND AIM: Green infrastructure (GI) is seen as a win-win solution to air pollution, reducing pollutant concentrations and thus, improving human health. However, the effects of GI on air quality are still unclear, and questions have been raised about the effectiveness of GI in mitigating air pollution. Before making generalisations about the benefit of GI to air quality, it is crucial to consider the GI-characteristics that influence air quality. So, to enhance the mitigation of air pollution, a holistic understanding of the effects of GI in cities is essential.This research reviews the academic literature addressing GI-related characteristics in cities, creating a holistic framework. METHODS: The mechanisms by which GI is considered to influence air quality were identified. A specific literature review was then conducted for each mechanism to extract the associated GI-characteristics. A holistic framework was created to help guide decision-makers in using GI solutions for improved air quality. RESULTS:Four mechanisms were identified by which GI influences air quality: deposition, dispersion, absorption, and biogenic emissions. Deposition is influenced by leaf form and micromorphological traits. The structure of the street, the meteorological conditions and the shape of the GI influence dispersion. Stomata conductance and chemical properties of the pollutant influence absorption. Plant emissions such as biogenic volatile organic compounds and pollen should be considered and minimised by appropriate species selection. Thus, maximising the positive effect of GI in cities on air quality will be the product of understanding a range of chemical and physical mechanisms in a highly site-specific context. CONCLUSIONS:Complex interactions between GI and site characteristics should be considered to maximise the benefits of GI in improving air quality. This research contributes to the air pollution mitigation field, explicitly helping to inform decision making for more health-promoting urban settings by optimising the expected benefits of GI through a holistic understanding of their impacts. KEYWORDS: Air pollution, built environment, and green spaces

Leaf morphology, photosynthesis and pigments change with age and light regime in savin juniper

• Savin juniper is an excellent species for desertification control in arid and semi-arid areas, where it typically establishes under the protection of nurse plants. Ultimately, established plants emerge into full sunlight as they grow, and this transition is accompanied by an increase in the preponderance of scale-like vs. needle-like leaf forms. • To test how age and variable sunlight environments affect shade tolerance in savin juniper, we established a pot study under field conditions with two age cohorts (1- and 4-year-old rooted scions) and three sunlight regimes (10%, 50% and 100% light transmittance). We measured growth, leaf parameters, photosynthesis, chlorophyll fluorescence and foliar pigments on a monthly basis (seven growing months per year, from 2015 to 2017). • Overall, there was little interaction for all variables, and both cohort and light regime had significant effects. Leaf form and spacing varied continuously, tending towards shorter, more closely spaced and more appressed scale leaves with higher dry leaf mass per area in older plants or under higher sunlight. There were no clear age-related patterns in carotenoids but both cohort and light had significant effects on gas exchange and chlorophyll fluorescence variables. • Savin juniper shows an intermediate tolerance to shade that changes with growth in that younger plants were less tolerant of full sun than older plants, consistent with its reliance on nurse plants for ultimate establishment in the open.

Geographic variation of leaf form among indigenous woody angiosperms in New Zealand

ABSTRACT Correlations of non-monocot woody angiosperm leaf traits to macroclimate are often used to reconstruct terrestrial paleoclimate under the assumption that macroclimate correlates with leaf phenotype are globally uniform, regardless of evolutionary history. Here, we evaluate if global trends in leaf trait variation with macroclimate are observed in the predominantly evergreen indigenous flora of New Zealand. A dataset of 557 indigenous woody dicot species and over 100,000 occurrences was employed to investigate community-level relationships of four leaf characters (leaf pubescence, margin teeth, area and length-to-width ratio) with geographic variation in temperature, precipitation, water deficit and solar radiation. Leaf area and the frequency of toothed leaves decline at higher latitudes in New Zealand. Variation in leaf pubescence and leaf teeth is associated primarily with measures of water availability, such as annual rainfall and annual water deficit; whereas leaf size is associated primarily with temperature. Variation in leaf length-to-width ratio was weakly correlated to climate parameters. The New Zealand relationship of leaf area with temperature aligns with global patterns, highlighting the importance of small leaves in limiting night-time chilling. The global negative correlation of leaf teeth with temperature is apparent in New Zealand trees and vines, but not in shrubs or all woody dicots combined. However, the primary correlate of leaf teeth in New Zealand is water availability, showing that the response of this trait to macroclimate is not globally uniform. The high occurrence of pubescent leaves in low rainfall and drought-prone environments in New Zealand suggests that the trait is associated with water retention in drier climates.