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The petiole anatomy of 26 species of Madhuca from Peninsular Malaysia was studied. Methods used in this study were petiole sectioning using a sliding microtome, staining, mounting and observation under light microscope. This is the first report on a comprehensive petiole anatomy of selected Madhuca species from Peninsular Malaysia. The results had shown that there were five types of petiole outlines, and ten types of vascular bundles on the petiole of species studied. All species have sclerenchyma cells in the abaxial side except in M. motleyana, which has clusters of sclerenchyma cells scattered throughout the cortex. The findings showed that two types of crystals and latex canal were shared in all species studied. Only five species out of 26 have trichomes on their petiole. The evaluated petiole anatomical characteristic features proved to be a useful tool for the taxonomic discrimination of the 26 studied species. [ABSTRACT FROM AUTHOR]

Key message: In urban shrub trees, the species-specific photosynthetic response and water-use properties are related to the xylem anatomy of the petiole. It is becoming essential to select urban tree species based on drought response in warm temperate regions, because water limitation is prone to occur in an urban environment, and furthermore, urban warming along with global warming intensifies drought stress even in relatively humid regions. We focused on leaf photosynthesis, water use efficiency, and leaf water relations as key factors for the evaluation of drought response in urban trees, and compared their responses to drought stress and re-watering (recovery) in five major urban shrub tree species planted in Japan. In addition, species-specific xylem anatomical traits in the leaf petiole were evaluated. The five species showed diverse responses to drought and recovery. Rhaphiolepis umbellata possessed both the highest photosynthesis (A) and highest intrinsic water use efficiency (A/gs) under drought, as well as full recovery in the midday leaf water potential (Ψmid). These results suggest that R. umbellata is the most favorable species as an urban tree among the five species. In contrast, A and A/gs in Rhododendron obtusum were only 19% and 55%, respectively, of those in R. umbellata under drought, along with incomplete recovery in Ψmid. The responses of A, A/gs, and Ψmid for the other three species were intermediate between R. umbellata and R. obtusum. We found that during recovery, the species-specific coordination between photosynthesis and leaf hydraulic traits was mediated by stomatal regulation. The species with large stomatal conductance had both high photosynthesis and high leaf hydraulic conductance, along with a large vessel area in the leaf petiole. The selection of trees with consideration of the drought response, along with appropriate watering management, will improve the photosynthetic ability, and thus, will enhance CO2 absorption by urban trees. [ABSTRACT FROM AUTHOR]

Commiphora species are of high medicinal importance. They are distributed in Saudi Arabia, mainly in rocky habitats and regions under mountains, including the east of Tihama, forming a distinct element of Saudi flora. The present study focuses on the botanical characterization of five species of Commiphora, i.e., C. erythraea, C. gileadensis, C. kataf, C. myrrha, and C. quadricincta. The morphological characters for each species were recorded comparatively, and their taxonomic relationships were examined using gross morphology by generating a UPGMA dendrogram, which separated the Commiphora species into two distinct groups. A dichotomous key was generated to facilitate the identification process of the plant, even by naked eye, by obvious characteristics. Because of the similarities in anatomical structure of the stem and petiole of most studied species, only the quantitative variations are illustrated comparatively. Seed macro- and micro-morphological characteristics were recorded comparatively to be used in the identification of a species in the case of leaf absence. The phytochemical study included measurements of total phenolic and flavonoid contents. The phytochemical results were correlated with the ethno-botanic survey. The traditional uses for all species were recorded using the questionnaire and open interviews method for data collecting. The results revealed that the most common Commiphora species that are traditionally used are C. myrrha and C. gileadensis. The study recommends more research on Commiphora species using more advanced techniques and tries to increase public awareness on the importance of these plants.

Commiphora species are of high medicinal importance. They are distributed in Saudi Arabia, mainly in rocky habitats and regions under mountains, including the east of Tihama, forming a distinct element of Saudi flora. The present study focuses on the botanical characterization of five species of Commiphora, i.e., C. erythraea, C. gileadensis, C. kataf, C. myrrha, and C. quadricincta. The morphological characters for each species were recorded comparatively, and their taxonomic relationships were examined using gross morphology by generating a UPGMA dendrogram, which separated the Commiphora species into two distinct groups. A dichotomous key was generated to facilitate the identification process of the plant, even by naked eye, by obvious characteristics. Because of the similarities in anatomical structure of the stem and petiole of most studied species, only the quantitative variations are illustrated comparatively. Seed macro- and micro-morphological characteristics were recorded comparatively to be used in the identification of a species in the case of leaf absence. The phytochemical study included measurements of total phenolic and flavonoid contents. The phytochemical results were correlated with the ethno-botanic survey. The traditional uses for all species were recorded using the questionnaire and open interviews method for data collecting. The results revealed that the most common Commiphora species that are traditionally used are C. myrrha and C. gileadensis. The study recommends more research on Commiphora species using more advanced techniques and tries to increase public awareness on the importance of these plants. [ABSTRACT FROM AUTHOR]

Background and Aims Petioles are important plant organs connecting stems with leaf blades and affecting light-harvesting ability of the leaf as well as transport of water, nutrients and biochemical signals. Despite the high diversity in petiole size, shape and anatomy, little information is available regarding their structural adaptations across evolutionary lineages and environmental conditions. To fill this knowledge gap, we investigated the variation of petiole morphology and anatomy of mainly European woody species to better understand the drivers of internal and external constraints in an evolutionary context. Methods We studied how petiole anatomical features differed according to whole-plant size, leaf traits, thermal and hydrological conditions, and taxonomic origin in 95 shrubs and trees using phylogenetic distance-based generalized least squares models. Key Results Two major axes of variation were related to leaf area and plant size. Larger and softer leaves are found in taller trees of more productive habitats. Their petioles are longer, with a circular outline and are anatomically characterized by the predominance of sclerenchyma, larger vessels, interfascicular areas with fibres and indistinct phloem rays. In contrast, smaller and tougher leaves are found in shorter trees and shrubs of colder or drier habitats. Their petioles have a terete outline, phloem composed of small cells and radially arranged vessels, fibreless xylem and lamellar collenchyma. Individual anatomical traits were linked to different internal and external drivers. Petiole length and vessel diameter increase with increasing leaf blade area. Collenchyma becomes absent with increasing temperature, and petiole outline becomes polygonal with increasing precipitation. Conclusions We conclude that species' temperature and precipitation optima, plant height, and leaf area and thickness exerted a significant control on petiole anatomical and morphological structures not confounded by phylogenetic inertia. Species with different evolutionary histories but similar thermal and hydrological requirements have converged to similar petiole anatomical structures. [ABSTRACT FROM AUTHOR]

• E. senticosus primary and secondary roots anatomy is analyzed for the first time. • Distribution of secretory canals is determined in perennial organs and leaves. • Secretory canals are continuously formed in the conductive phloem. • Epithelial cells-sheath cells complexes are persistent in 4 year annual rings. • Sieve tubes-companion cells are obliterated after the first vegetation period. • Autofluorescence suggests secondary metabolites occurrence in parenchyma cells also in addition to secretory structures. Eleutherococcus senticosus (Araliaceae) is widely used as adaptogen in herbal medicine. Since comprehensive anatomical analysis of its vegetative organs was not available, the present study aimed at providing the reference data on the structure of leaves and roots, under- and aboveground stems of 1–4 year-old plants by means of conventional light microscopy. In the primary structure, roots were di- or triarch, with secretory canals facing protoxylem. Concurrently with cambium initiation, additional pericyclic secretory canals differentiated close to the existing ones. In the root secondary structure, secretory canals were formed in the conductive secondary phloem and maintained in the nonconductive one. Stem primary structure encompassed uniseriate epidermis with scant prickles, primary cortex and stele. Primary cortex was composed of collenchyma, chlorenchyma, ground parenchyma with secretory canals and ca. triseriate starch sheath. In outer stele (pericycle) strands of sclerenchyma fibers (stereids) differentiated, alternated with parenchyma. In the ring of open collateral bundles, cambium became continuous concurrently with (sub)epidermal initiation of phellogen. In the wide pith, ground parenchyma occurred, with a few secretory canals close to protoxylem. Secondary structure stems retained the cortical tissues in the 4th year; new secretory canals appeared in the conductive secondary phloem. The epithelial cells/sheath cells complexes were maintained even in the oldest nonconductive phloem (and in the cortex) in stems of 4 year-old plants, while the successively formed sieve tube-companion cell complexes functioned till the end of the vegetation periods only. The bifacial leaves exhibited shade adaptation in chlorenchyma structure; secretory canals were formed mainly in veins' phloem. [ABSTRACT FROM AUTHOR]

The article presents the results of the study of the petiole anatomy peculiarities of the hybrids between Aigeiros and Tacamahaca sections. Petiole anatomic structure was found to be helpful in assigning taxa to a section and to find intersectional hybrids, which is actual for studying populations in natural and anthropogenic hybridization zones. Cross sections made in the upper part of petioles were used for analyzing anatomic traits by light microscopy. All representatives of the Aigeiros section have linear form of the vascular system, consisting of 3–5 rings, with a rounded contour of the petiole adaxial side. In the Tacamahaca section taxa the vascular system is highly arched, and the adaxial side is cordate. The study of the hybrids between species of the same section revealed that such hybrids inherit anatomy features common for the section. We can consider such traits as adaxial side shape and vascular system type to be the most important markers for intersectional hybrids. Truncated or notched shape of the adaxial contour and vascular system type were found to be characteristic features of hybrids, as small notches in their petioles’ upper part are common for all hybrids. Most of hybrids have small notches, rather than grooves, in the upper part of their petioles. Most of the intersectional hybrids have transitional shape of vascular system. The anatomy of Populus × sibirica petioles confirmed earlier results that it is a hybrid cultivar, that originated as a result of crossbreeding between Aigeiros and Tacamahaca section species.

We assessed the petiole anatomy of 8 species of Sri Lankan Cinnamomum (C. capparu-coronde, C. citriodorum, C. dubium, C. litseaefolium, C. ovalifolium, C. rivulorum and C. sinharajaense and C. verum) belonging to the family Lauraceae using light microscopy in the petiole anatomy for identification and classification of species. This is the first report on comprehensive petiole anatomy in Cinnamomum species. The distinctive, important and key taxonomic characteristics of the petiole include the shape and outline of the petiole, the presence of winged extensions, surface grooves on upper surface, presence or absence of trichomes, structure of vascular bundle and stone cell characters (shape, structure, pits and fissure size). These identified petiole characters provide the additional information for the identification of Cinnamomum species. Almost all the characters studied had little difference within a species but vary among the species. However, shape of epidermal cells was relatively constant for all species. All polymorphic characters were used for Principal Component Analysis (PCA) and species were divided into three main clusters. The PCA revealed that acicular crystals, cluster of crystals, trichomes and trichome abundance contribute to the first component that account for 31.76% total variance. Shape of the petiole, upper surface wings and raphides are the major loading characters to the second component. Therefore, anatomical structures of the petiole are useful in the identification and may help for crop improvement, conservation, management and future usefulness of germplasm resources of Cinnamomum species.

Although the leaf economic spectrum has deepened our understanding of leaf trait variability, little is known about how leaf traits scale with leaf area. This uncertainty has resulted in the assumption that leaf traits should vary by keeping the same pace of variation with increases in leaf area across the leaf size range. We evaluated the scaling of morphological, tissue-surface and vascular traits with overall leaf area, and the functional significance of such scaling. We examined 1,271 leaves for morphological traits, and 124 leaves for anatomical and hydraulic traits, from 38 trees of Cecropia obtusa Trécul (Urticaceae) in French Guiana. Cecropia is a Neotropical genus of pioneer trees that can exhibit large laminas (0.4 m2 for C. obtusa), with leaf size ranging by two orders of magnitude. We measured (i) tissue fractions within petioles and their second moment of area, (ii) theoretical xylem hydraulic efficiency of petioles and (iii) the extent of leaf vessel widening within the hydraulic path. We found that different scaling of morphological trait variability allows for optimisation of lamina display among larger leaves, especially the positive allometric relationship between lamina area and petiole cross-sectional area. Increasing the fraction of pith is a key factor that increases the geometrical effect of supportive tissues on mechanical rigidity and thereby increases carbon-use efficiency. We found that increasing xylem hydraulic efficiency with vessel size results in lower leaf lamina area: xylem ratios, which also results in potential carbon savings for large leaves. We found that the vessel widening is consistent with hydraulic optimisation models. Leaf size variability modifies scaling of leaf traits in this large-leaved species. [ABSTRACT FROM AUTHOR]

The study investigated the leaf architecture and petiole anatomy of eight Dipterocarpus (Dipterocarpaceae) species growing in Mount Makiling Forest Reserve (MMFR) in the Philippines to delineate the species, especially during their non-flowering phase. Leaf and petiole samples from MMFR were examined following the manual on leaf architecture studies. Freehand technique was used to examine the stomata and petiole characters. A UPGMA phenogram was then generated to determine the relationships among Dipterocarpus species using 26 leaf and petiole characters. The most useful characters to delineate Dipterocarpus species are the presence of trichomes, the arrangement of vascular bundles (medullary and outer vascular bundles), areolation, fimbrial vein, and leaf size. Other characters viz., the laminar ratio, blade class, laminar shape, base shape, margin type, and intersecondary, and layers and shape of parenchyma and collenchyma cells were useful as unifying characters. Therefore, certain characters of the leaf architecture and petiole anatomy may be used as taxonomic markers to delineate and correlate the Dipterocarpus species in the Philippines particularly during the nonflowering phase of the species. However, further investigations using samples from the wild populations of the species and molecular techniques may be done to elucidate the taxonomic use of the characters presented in this study. [ABSTRACT FROM AUTHOR]

The study examined the taxonomic value of petiole anatomy of 63 species belonging to Litsea, Neolitsea and Lindera. The middle part of the petiole was sectioned and observed under a light microscope. The findings revealed valuable anatomical characteristics in outline shape, vascular bundles arrangement type, trichome types, presence of cuticle, crystals, brachysclereid, sclerenchyma and idioblast cells. Three shapes of petiole outline and six types of petiole vascular bundles arrangement were observed. Based on the results, Lindera and Litsea are more related due to the type of vascular bundles arrangement. Sclerenchyma and brachysclereid were also useful in differentiating genera in Litsea complex. This study has proven that anatomical characteristics have a taxonomic value which could be used as a diagnostic tool in identifying the genera and species in Malaysian Litsea complex. [ABSTRACT FROM AUTHOR]

The anatomy of the epidermis, transverse sections of the leaves and petioles of three species of Alocasia (Schott) G. Don in Nigeria were examined in this study in order to report any anatomical characters of taxonomic importance among them. The species are Alocasia cucullata (Lour.) Schott, A. macrorrhiza (L.) G. Don, and A. plumbea (Schott) G. Don. Standard procedures were followed in preparing the epidermal peels, transverse sections of the leaves, and the three regions of the petiole: proximal, median and distal regions. Generic characters among the species include polygonal to irregular epidermal cell shape, a straight anticlinal wall pattern, elliptic and circular-shaped stomata, brachyparacytic stomatal complex type, round abaxial petiole outline and the presence of druses, raphides, and starch grains in the petiole. The presence of peltate trichomes on the adaxial surface of A. cucullata as well as additional anomocytic stomata complex on both of its surfaces and mucilaginous cells in A. plumbea which are the diagnostic features were discussed. Other diagnostic features include the presence of druses on the abaxial surfaces of A. macrorrhiza and A. plumbea, highest stomata index in A. macrorrhiza, collenchyma type, tannins and adaxial petiole outline. The Alocasia species can be separated based on their leaf anatomical features. [ABSTRACT FROM AUTHOR]

• Lamiaceous species were observed for petiole microanatomical traits. • Angular collenchymatous cells are the significant taxonomic character. • Petiole anatomical revealed variations in vascular bundles arrangements. • Morpho-anatomy of petiole in Lamiaceae traces the phylogenetic linkages. Microanatomical traits are one of the reliable features that are exploited for accurate species identification. The petiole anatomy of selected species Lamiaceous species is well explained in depth and linked to their systematic relevance. This study aimed to provide the taxonomic value of petiole micromorphology of 15 species of Lamiaceae. The petiole was sectioned with Microtome to visualize under a light microscope to measure micromorphological qualitative and quantitative attributes. The qualitative including petiole shape, vascular bundles (VBs), the shape of the epidermis, and collenchymatous and parenchymatous cells showed diversified traits. The quantitative traits such as the number of VBs, vessel elements, outlines, parenchyma, collenchyma, and upper and lower epidermis cells were measured. The highest mean length of VB (7.7 µm) was noticed in Stellaria linearis Benth. The highest VBs nine in number (3 central and 6 subsidiary) was examined in Salvia argentea L. The maximum vessel element (95 in number) were present in Thymus linearis Benth. Winged petiole was observed in nine taxa covered by uniseriate trichome hairs to be a valuable aspect in the taxonomy of Lamiaceae. The petiolar features-based statistical analysis was performed using dendrogram clustering and principal component analysis (PCA) accounting for the delineated of Lamiaceous species. This study describes the morpho-anatomy of petiole in the Lamiaceae can be further elaborated for correct identification using a phylogenetic-based micromorphological taxonomic approach. [ABSTRACT FROM AUTHOR]

We conducted a comparative anatomical study of the petiole of 16 taxa belonging to the tribe Sorbarieae (Rosaceae) (Adenostoma, 2 spp.; Chamaebatiaria, 1 sp.; Sorbaria, 6 spp., 3 vars., and 1 forma; and Spiraeanthus, 1 sp.) and the related genus Lyonothamnus (1 sp. and 1 ssp.). The distal, medial and proximal regions of petioles were transversely sectioned using conventional embedding and staining methods. Cuticles, crystals, trichomes and pericyclic fiber patterns were observed and studied. Three types of vascular nodal patterns were recognized: Type 1 was seen in Chamaebatiaria, Lyonothamnus, and Spiraeanthus (simple‐trace nodal pattern with slightly curved or U‐shaped vascular bundle); type 2 was found in Adenostoma (multiple‐traces nodal pattern with free vascular bundles); and type 3 was unique to Sorbaria (bundles fused to form a siphonostele nodal pattern). Some petiolar anatomical characteristics (e.g. cuticles, crystals, trichomes, vascular nodal pattern, and pericyclic fiber patterns) were found to provide useful information for taxonomic studies within Sorbarieae. On the basis of these characteristics, a dichotomous key for identification at the generic/specific level is provided. We also report a structural change in the vascular bundles from the stem‐leaf transitional zone to the leaf medial zone. [ABSTRACT FROM AUTHOR]

The anatomy and micromorphology of the vegetative organs and calyx of Stachys scardica (Griseb.) Hayek were investigated using light (LM) and scanning electron microscopy (SEM). The analysis of the anatomical structure of stem, leaf and leaf petiole showed the presence of an additional adaxial phloem in the vascular bundle of the petiole that was recorded exclusively in species belonging to the subgenus Betonica. On the surface of studied plant parts, three types of trichomes were found: simple nonglandular uniseriate multicellular, nonglandular branched elongated and glandular peltate trichomes. The present study shows that certain micromorphological and anatomical features of Stachys taxa are valuable taxonomic characters. [Projekat Ministarstva nauke Republike Srbije, br. 173029]

Water stress is considered as one of the most widespread limitations to sugar beet productivity and yield stability. Since leaf is the most significantly affected organ by drought, we focused on the petiole histological features of ten sugar beet genotypes that previously showed divergent responses to lack of water in the field. The aim was to calculate volume densities of petiole different tissues and determine the histological sources of the genotypic differences in the breeding material with respect to water use efficiency. Comparative histological analysis of the petiole was performed using classic anatomical (proximal and distal segments) and stereological methods. The plants were grown in semi-controlled glasshouse conditions. The general structure of the sample variability was established by Principal component analysis, based on the correlation matrix data. This study suggests that determination of the variation in the histological characteristics of the petioles can play an important role in water management in plants. The results reveal a higher level of variability in morphometric parameters due to the fact that petiole cross-section shapes change with its maturity. Characteristics, such as (i) petiole shape, (ii) arrangement and number of vascular bundles, (iii) number and size of vessels, (iv) volume density and distribution of collenchyma, and (v) volume density of parenchyma are promising criteria that can help in the selection of more drought tolerant genotypes. [ABSTRACT FROM AUTHOR]

We studied the anatomy of a rare narrow endemic species belonging to the Slovenian flora - Hladnikia pastinacifolia Rchb. Hladnikia is a monotypic genus with distinct taxonomic position within the Apiaceae family. The anatomical characteristics revealed by light and fluorescence microscopy provided new insights regarding the pollen, leaf and root characteristics of H. pastinacifolia, improving the understanding of its biology and ecology. Pollination, drought tolerance, life cycle and unattractiveness to herbivores explain the species' persistence in time. Autofluorescence localized bioactive substances within secretory ducts and oil ducts. [ABSTRACT FROM AUTHOR]

Studies of angiosperms have associated the mechanical design of petioles with leaf form and the occurrence of simple and compound leaves. Petiole anatomy can respond differently, according to different leaf forms, to maintain plant architecture. The present study evaluated whether this premise applies to fern leaf architecture. Leaves of five ferns ( Blechnum binervatum (Poir.) C.V. Morton & Lellinger, Ctenitis falciculata (Raddi) Ching, Megalastrum connexum (Kaulf.) A.R. Smith & R.C. Moran, Microgramma squamulosa (Kaulf.) de la Sota, and Serpocaulon catharinae (Langsd. & Fisch.) A.R. Sm.) from a remnant of an Araucaria Forest in southern Brazil were collected and their morphological and anatomical traits were analyzed. Results indicate that the biomechanical patterns of these terrestrial and epiphytic ferns are similar to those reported for angiosperms, except for the presence of subepidermal sclerenchyma in fern petioles. Independently of leaf form, the rigid structure of fern petioles appears to be an important adaptation to biomechanically support leaf position for maximum light interception in forest understories. [ABSTRACT FROM AUTHOR]

Studies on the leaf epidermal characters and petiole anatomy of four species of Citrus L. viz., C. limon (L.) Burm., C. paradisi Macf., C. reticulata Blanco and C. sinensis (L.) Osbeck were carried out to establish and document their foliar anatomical characters with the aim of separating them from the modified varieties been cultivated globally. Leaf epidermal features that revealed close relationship among these taxa include hypostomatic condition, stomata shape and type, presence of secretory cavity on the adaxial surface, and polygonal shape of epidermal cells. The absence of secretory cavity on the abaxial surface separates C. limon and C. sinensis from others. Petiole anatomy revealed that the outline is flat without ribs in C. sinensis, convex with short ribs in C. reticulata, convex with long ribs in C. paradisi while in C. limon it is circular without ribs. Presence of trichomes and crystals distinguishes C. paradisi from the rest. [ABSTRACT FROM AUTHOR]

The flora of Iran is rich in endemic species of Apiaceae, many of which have been poorly investigated and whose phylogenetic relationships are unknown. We investigate the relationships within five genus groups of Apiaceae subfamily Apioideae native to the Flora Iranica region using nuclear ribosomal DNA ITS sequences. Supplementary comparative data come from morphology and, for one of these groups, petiole anatomy and palynology. These groups of Apioideae are circumscribed initially on the basis of morphological similarities andlor the results of previous molecular systematic investigations, then redefined and confirmed as monophyletic based on the results of maximum parsimony, maximum likelihood, and Bayesian analyses of ITS sequences from a broader sampling of species. These five redefined groups and their constituent genera include the Cachrys group (Alococarpum, Azilia, Bilacunaria, Cachrys, Diplotaenia, Eriocycla, Perulago, Prangos), cynihocarpum group (cymbocarpum, Ducrosia, Kalakia), Ferula group (Dorerna, Perula, Leutea), Johrenia group (Holandrea, Johrenia, Johreniopsis) , and Opopanax group (Opopanax, Smyrniopsis). Azilia eryngioides is a sister group to all other members of the Cachrys group, coincident with its highly unusual morphology. The monotypic Alococarpum may be transferred into Prangos pending further study. The Cymbocarpum group is contained within tribe Tordylieae, the latter now expanded to include Cymbocarpum, and the monotypic Kalakia is submerged within Cymbocarpum. Dorema and Leutea arise from within a paraphyletic Ferula in tribe Scandiceae; nomenclatural changes are suggested, but must await supporting evidence from chloroplast DNA. Neither Johrenia nor Johreniopsis of the Johrenia group (tribe Selineae) is monophyletic, with all examined species except Johrenia golestanica arising from within a paraphyletic Holandrea. Holandrea may be transferred into Johrenia and J. golestanica may constitute a new, monotypic genus pending confirmation from further investigations. Opopanax and Smyrniopsis, traditionally treated in two tribes, are confirmed as monophyletic sister groups in the Apioid superclade. They share similar morphological attributes and are closely allied to Petroedmondia, Magydaris, and Crenosciadium. [ABSTRACT FROM AUTHOR]

Water relations in woody species are intimately related to xylem hydraulic properties. High CO2 concentrations ([CO2]) generally decrease transpiration and stomatal conductance (gs), but there is little information about the effect of atmospheric [CO2] on xylem hydraulic properties. To determine the relationship between water flow and hydraulic structure at high [CO2], we investigated responses of sun and shade leaves of 4-year-old saplings of diffuse-porous Betula maximowicziana Regel and ring-porous Quercus mongolica Fisch. ex Ledeb. ssp. crispula (Blume) Menitsky grown on fertile brown forest soil or infertile volcanic ash soil and exposed to 500 µmol CO2 mol-1 for 3 years. Regardless of species and soil type, elevated [CO2] consistently decreased water flow (i.e., gs and leaf-specific hydraulic conductivity) and total vessel area of the petiole in sun leaves; however, it had no effect on these parameters in shade leaves, perhaps because gs of shade leaves was already low. Changes in water flow at elevated [CO2] were associated with changes in petiole hydraulic properties. [ABSTRACT FROM AUTHOR]

• Distinctive character for taxonomy: elongate glandular trichomes. • Distinctive: cuticle ornamentation on epidermal and guard cells, and on trichomes. • Distinctive: anticlinal walls sinuosity, mesophyll distribution and hypodermis. • Presence of tuft-domatia on connection between midrib with secondary veins. • All species have: glandular trichomes, sclereids, outer cuticular ledge in stomata. The genera Chionanthus is composed by around 100 species distributed worldwide, in tropical and temperate regions of Asia, Africa, Americas and Australia. In Brazil, Chionanthus is the most abundant genera among the Oleaceae family, with 11 species described, nine of them being endemic. The lack of distinctive morphological aspects hinders the identification of some of these species. The aim of this work is to use the leaf anatomy as a tool to the taxonomy of Brazilian native species of Chionanthus , focusing on displaying features that ease their identification. The anatomy of fully expanded leaves was analyzed from 10 species: Chionanthus crassifolius , C. ferrugineus , C. filiformis , C. fluminensis , C. greenii , C. micranthus , C. parviflora , C. subsessilis , C. tenuis and C. trichotomus. The samples, obtained from herborized plants, were rehydrated and cross-sections were made in the middle of the leaf blade, on the petiole and, also, both of the epidermis were dissociated. The occurrence of common anatomic features to Oleaceae were noticed, such as the presence of sclereids and glandular trichomes. The description of the leaf anatomy has permitted to determine the distinctive characteristics between species, such as the shape of the petiole, the vascular system arrangement in the petiole and in the midvein; the presence of papillate epidermal cells; cuticle ornaments; elongate glandular trichomes, sinuosity on the anticlinal walls of the epidermis, presence of hypodermis; differentiation of the mesophyll; and the contour of the midrib on the abaxial surface. [ABSTRACT FROM AUTHOR]