The effect of shade on leaf structure and physiology of tree seedlings from a mixed dipterocarp forest

This study builds upon past work investigating seedling leaf physiology and structure among tropical trees. We seek to explain how related and unrelated species and genera co‐occur in relation to varying amounts of shade. Seedlings of eight Sri Lankan rain forest tree species in three genera (Dipterocarpus, Mesua, Shorea section Doona) were grown for 2 years in four treatments that simulated a variety of shade environments across the understorey of a rain forest. All three genera comprise major canopy tree species of mixed dipterocarp forest, a widespread and important Asian tropical forest type. Compared with the other genera, Dipterocarpus spp. had the largest leaves, the thinnest leaf blades and relatively high rates of stomatal conductivity across all shade treatments, making them water‐loving species sensitive to droughty soils. Mesua spp. had intermediate sized leaves, with the thickest leaf blades and palisade mesophyll layers, the highest stomatal densities, the smallest aperture sizes and the lowest rates of stomatal conductance, making them the most water conservative. Shorea spp. were generally intermediate in blade and palisade mesophyll dimensions between Dipterocarpus spp. and Mesua spp., but they had the smallest leaves. Greater differences among genera than among species within genera were apparent, but species differences within genera were also apparent. Differences among genera and species conform to their known successional status and topographical affinities and provide a more comprehensive understanding of species site adaptation. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 167 , 332–343.     

Indeterminate leaves of Chisocheton (Meliaceae): survey of structure and development

Pinnately compound leaves in the Malesian genus Chisocheton (Meliaceae) have leaf-tip buds that continue to produce new pinnae (leaflets) periodically for many years. Juvenile leaves form a terminal pinna in place of the leaf-tip bud found in adult leaves. The histology of an old leaf-tip bud is similar to the entire leaf primordium in other species of Meliaceae with large pinnate leaves (e.g. Chukrasia and Dysoxylum ) which serve as examples of more typical leaves. Pinna initiation from this meristem continues after the first stage of leaf expansion as seen in the relatively constant number of pinna primordia in a large sampling of leaf-tip buds of varying ages. Structure and development are compared in leaves of nine species of Chisocheton , out of a total of approxiamtely 50 species in the genus. Species having small leaves (e.g. C. pentandrus ) show more branch-like, indeterminate leaf growth as compared with species with large leaves (e.g. C. macranthus ). The structure and development of leaves of Chisocheton are like the similar indeterminate leaves of the American and African genus Guarea . Some authors have used the indeterminate leaves of Chisocheton and Guarea as examples of intermediate organs showing 'fuzzy morphology' or 'partial homology.' Nevertheless, these unusual organs are considered here as being homologous with leaves of other Meliaceae based on their position, histology and ontogeny. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 139 , 207–221.     

Characterization of Hormonal Complex in Pea Phenotypes Differing in Leaf Morphology

Two genotypes of the pea (Pisum sativum L.) with wild-type leaves (variety Orlovchanin, Af/Af genotype) and the afila morphotype (aphyllous variety Nord, af/af genotype) were compared in terms of growth performance and hormonal characteristics of different leaf parts and the whole plant. The replacement of leaflets by tendrils in the afila variety led to a reduction in total dry weight and the area of photosynthesizing surfaces. The loss of leaflets was partly compensated for by rapid expansion of stipules at early stages of plant development and by the hypertrophy of tendrils at later stages. The excessive development of stipules in afila plants was paralleled by the increase in IAA and cytokinin level in their tissues. The hypertrophied development of tendrils and chlorophyll accumulation in tendrils of afila plants was correlated with a high IAA and cytokinin content at a low ABA background level. The elevated content of ABA in tissues of wild-type plants was associated with the preferential development of leaflets and a larger transpiratory surface compared with those in the afila form. It is assumed that this feature ensures the turgescence of wild-type plants. The possible involvement of phytohormones in growth and morphogenesis of pea mutants is discussed.     

Vegetative morphology and trait correlations in 54 species of Commelinaceae

The morphospace of 54 species of Commelinaceae from nine genera was examined with simultaneous attention to constraints, adaptive hypotheses and relatedness. Eleven morphological traits, including leaf length and width, angle between the leaves and internode distances, were measured for each species and analysed by principal components analysis and nested analysis of variance. The results revealed a significant signal of relatedness in vegetative morphology; genus explained 20–50% of the variance in a single trait. The relationships between some traits are consistent with adaptive explanations. The findings are consistent with the prediction that evolution for optimal phyllotaxis should be relaxed as self‐shading decreases, and that light availability governs leaf size and branching patterns. Constraints potentially explain some trait correlations, and support was found for the hypothesis that structural constraints govern leaf size and internode size correlations. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 257–268.     

Leaf epidermal micromorphology of Cercis (Fabaceae: Caesalpinioideae)

The micromorphology of leaf epidermal cells and stomata of all eight species and one form (11 samples) of Cercis were observed by scanning electron microscopy and light microscopy. Both the adaxial and abaxial epidermal cells are polygonal or irregular in shape; the anticlinal walls are straight and arched or undulate. Two types of stomata, which occur only on the abaxial surface of the leaves, are found in the genus. The atypical paracytic type is present in only one species, Cercis chingii, and the anomocytic type is present in all other species. Interspecific differences are minor in the genus with regard to leaf epidermal characters, except for C. chingii, which is characterized by atypical paracytic‐type stomata, a two‐lipped outer stomatal rim, the highest stomatal density and undulate and densely pitted anticlinal walls in the adaxial epidermis. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 539–547.     

INVESTIGATIONS OF ANGIOSPERMS FROM THE EOCENE OF NORTH AMERICA: STIPULATE LEAVES OF THE RUBIACEAE INCLUDING A PROBABLE POLYPLOID POPULATION

A comparative study was made of the gross morphology, fine venation and cuticular features of Leitneria fioridana Chapman, the single living representative of the order Leitneriales and Leitneria eocenica (Berry) Brown, presumbaly a related fossil species. In addition to the type material, newly collected fossil specimens were investigated from clay pits in the Middle Eocene, Claiborne Formation, of western Tennessee and Kentucky. Foliate stipules attached to the petioles of several specimens suggest the assignment of this fossil leaf type to the genus Leitneria is incorrect. The nature of the gross morphology, fine venation and cuticular features confirms the misidentification. Previously, various specimens of this fossil leaf type have been placed in eight species of seven genera in seven families of six angiosperm orders, none of which are correct systematically. The gross morphology, venation and cuticular characters of the fossil leaf are distributed among a few extant South American genera of arborescent Rubiaceae. The fossil is an extinct rubiaceous leaf type which cannot be placed within a single modern subfamily, tribe or genus of the family. The organ genus, Paleorubiaceophyllum is proposed for these leaves. Three varieties of a single fossil species, P. eocenicum, are recognized. One variety with epidermal cells nearly twice the size of the others may represent a polyploid population.     

Leaf epidermal character variation and evolution in Gaultherieae (Ericaceae)

The taxonomic value and evolutionary significance of 30 leaf epidermal characters from 238 samples representing 127 species of all seven genera in the tribe Gaultherieae (Ericaceae) and two outgroup genera were investigated by scanning electron microscopy. The character states were coded and optimized onto a maximum‐likelihood tree based on previous molecular data with Fitch parsimony and hierarchical Bayesian analysis to trace the evolution of character states throughout all internodes in the phylogenetic tree for Gaultherieae. Leaf epidermal characters were found to be largely consistent within species, but highly variable at interspecific and higher taxonomic levels. The most recent common ancestral states of 15 characters diagnosed various lineages recovered from prior studies, some with no prior morphological support. Relatively high frequencies of state change occur in the eastern Asian clade Gaultheria series Gymnobotrys + Diplycosia, the American clade G. subsection Dasyphyta p.p., the core East Asian clade and the Australia/New Zealand clade. The characters with the highest frequencies of state change are the outer stomatal ledge ornamentation type, the stomatal apparatus level, stomatal density and area, and the type of abaxial trichomes. These character state change patterns may provide insight into the ecological adaptions of Gaultherieae during their evolutionary history. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 178 , 686–710.     

Anatomical structure and secretion compounds of colleters in nine Ilex species (Aquifoliaceae) from southern South America

In order to clarify whether the structures observed at the base of the petiole of the genus Ilex are colleters resulting from stipules, the anatomy, vascularization and secretions of these supposed glandular structures were analysed in nine species. This is the first report of colleters in Ilex. Stipular colleters replace the stipules in all species studied and are characterized by the presence of vascular traces. In addition to the stipular colleters, three other types of colleter were distinguished: standard and lachrymiform colleters found on the leaf teeth or crenations, and sessile colleters found on the margins of the floral bracts. Their basic structure consists of a central core of parenchymatous cells surrounded by one layer of palisade secretory epidermal cells. Histochemical tests were also performed on secretions; proteins were found in the secretions studied, but glucose was not. The glandular origin of the stipular colleters is confirmed on the basis of their position, secretions and anatomy. Analyses of the colleter‐secreted proteins distinguished two different groups of Ilex species. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160 , 197–210.     

EARLY LEAF ONTOGENY AND SHOOT DEVELOPMENT IN BROWNEA ARIZA (LEGUMINOSAE)

Brownea ariza Benth. (Leguminosae: Caesalpinioideae) shows early shoot tip abortion and subsequent renewal growth from the pseudoterminal bud. This species is unusual in that the entire shoot system is formed before flushing from the bud occurs, shoot tip abortion occurs during flushing, and the aborting portion contains three to six leaves as well as primordial structures varying from hood to peg shape. This study focused on the morphological changes from initiation of scale and foliage leaf primordia in the “resting” renewal bud through bud elongation to flushing and bud abortion. Scanning electron microscopy revealed that embryonic scale leaves are hood-shaped while foliage leaf primordia show early segmentation into leaflets and stipules. No transitional stages were observed. Bud scales and foliage leaves show opposite developmental trends. In bud scales, length at maturity increases from first to last formed, while length decreases in sequentially formed foliage leaves. Early in leaf development the stipules keep pace with the elongation of the rachis. When the bud reaches about one half of its final length the leaf rachis begins to exceed the lengths of its stipules. This young rachis terminates in a distinct mucro that persists until maturity at which time it abscises. Growth patterns indicate that mucro and rachis are a single developmental unit. The early abortion of a shoot tip containing several leaves cannot be easily rationalized. Previous suggestions have involved maintenance of form and ecological adaptation. We add the possibility of elimination of cell progeny encumbered by mutations. From this and other studies of this group, it is clear that at maturity leaves of different species may look alike, e.g., Hymenaea and Colophospermum are bifoliolate; Brownea, Saraca, and others are multifoliolate. However, early stages of leaf ontogeny are quite diverse and may be of systematic value, since these early differences are lost or masked by later development.     

Three new species of Galipea (Rutaceae, Galipeinae) from Brazil

Three new species of Galipea (Rutaceae, Galipeinae) are described and illustrated. Galipea carinata Pirani sp. nov. is known from the pluvial tropical forest in southern Espírito Santo State, eastern Brazil, and its main diagnostic features are the urceolate and conspicuously keeled calyx, the relatively short (14–16 mm) corolla tube, the long pedunculate, divaricate and loosely branched inflorescence, with few flowers crowded on tip of side branchlets, and the chartaceous leaflets, with lateral veins very prominent on both sides of the blade. Galipea revoluta Pirani sp. nov. is probably endemic to the coastal hygrophyllous Atlantic Forest in southern Bahia, eastern Brazil, and is very distinct by its mostly unifoliolate leaves, with a leathery, shiny lamina that is thickened and usually revolute at margin, by its calyx with large glands only at the base, and median nerve on each sepal. Galipea congestiflora Pirani sp. nov. is from forests on terra firme (non-inundated vegetation) of eastern Amazonia, most of them from the State of Pará, some others from eastern Maranhão and north of Tocantins. It is characterized mainly by 3-foliolate, chartaceous and dull leaves; a dense, corymbiform thyrsoid (partial inflorescences very short, crowded on top of the peduncle), which is smaller than the leaves; relatively large capsules (the largest in the genus) with an acute rim at the tip of each valve, and by the marmorate surface of the seeds. A brief discussion on the relationships of the new taxa to other species of Galipea is provided.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144, 365–373.     

Geometric morphometrics and leaf phenotypic plasticity: assessing fluctuating asymmetry and allometry in European white oaks (Quercus)

Because plants are unable to move away from unfavourable habitats and environmental perturbations, leaf phenotypic plasticity facilitates light absorption and gas exchange. Oaks (Quercus spp.) are particularly known for their adaptability and plastic phenotypes, and leaf allometry and developmental instability may represent important mechanisms for their adaptation to environments and evolution. Because of its important role in the adaptation of plant populations to different environments, allometry can be involved in diversifying selection. Developmental instability is related to environmental perturbations and stresses by producing random deviations in structures characterized by bilateral symmetry, such as oak leaves. In addition, developmental instability can also arise from genetic bottlenecks or as a result of hybridization. The splitting of symmetric and asymmetric components of variation and their separate analysis allows the variability in leaf shape traits to be summarized, reducing the variation produced by developmental instability. The geometric morphometric approach is a useful method for the study of leaf asymmetry and allometric patterns. This method provides an important tool for the visualization of shape attributes that characterize species with highly variable leaf phenotypic patterns. In this study, leaf shape and size variability of three white oak species was investigated by means of a two‐dimensional landmark‐based method providing improved knowledge of variance partitioning, species discrimination, fluctuating asymmetry and allometric patterns of variation resulting from the different analyses. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 335–348.     

Shoot and compound leaf comparisons in eudicots: dynamic morphology as an alternative approach

Recent developmental studies suggest that the compound leaf is a more or less incompletely developed shoot. Instead of treating compound leaves and shoots as non-homologous, this interpretation draws a continuum between them. The present work considers the plant as a hierarchical series of units on which similar developmental processes are at work, and where each level (shoot, compound leaf, leaflet) is 'repeated' by the next higher level. Measurements related to the expression of developmental processes operating on leaves at the shoot level and on leaflets at the compound leaf level were used to determine if similar processes are at work at these different levels during early stages of organogenesis. Plants with compound leaves showing acropetal leaflet inception, representing a total of 16 species from ten eudicot families, were studied. Based on several types of quantitative analyses, there appears to be a continuum between so-called shoots, compound leaves and leaflets in the species studied. This perspective, qualified as dynamic morphology, both parallels and complements the classical interpretation.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 143, 219−230.     

Leaf epidermal features of Lithocarpus (Fagaceae) from China and their systematic significance

The leaves of 52 species of Lithocarpus in China were studied. The adaxial leaf epidermis was investigated by light microscopy. Epidermal cells of the adaxial surface were classified into three types on the basis of the outline of their anticlinal walls, i.e. sinuate, straight and curved. The abaxial leaf epidermis was investigated by light microscopy and scanning electron microscopy. The following types of trichome were observed: appressed parallel tuft, stellate, fused stellate, papillae, stipitate fasciculate, solitary unicellular, appressed laterally attached unicellular, curly thin‐walled unicellular, bulbous and thin‐walled peltate. The fused stellate, appressed laterally attached unicellular and curly thin‐walled unicellular trichomes were reported in Lithocarpus for the first time. The appressed parallel tuft trichome, which is recognized as a salient characteristic of Lithocarpus, was not found in 15 species. A cladistic analysis was performed on the basis of the leaf epidermal features. According to the leaf epidermal features and several morphological characteristics, 26 of the 52 species could be divided into seven groups. Similar groups can be found in Barnett's and Camus' systems. The trichomes of four genera in Fagaceae are listed and compared. Lithocarpus had 14 types of trichome, 11 of which were identical to types found in Quercus, more than in Castanopsis and Cyclobalanopsis. The evolutionary trends of trichomes in Fagaceae are discussed and a new point of view is raised. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 168 , 216–228.     

Revision ofFagonia species (Zygophyllaceae) with tri- to unifoliolate and simple leaves

Summary A taxonomical revision of3 Fagonia groups, viz. the complexes ofF. arabica, F. bruguieri andF. indica, including the interrelationships between their species, is presented. These complexes are characterized by their compound tri- or reduced unifoliolate leaves. Among the truly simple-leaved species, viz.F. socotrana, F. harpago andF. ovalifolia, the confusion betweenF. socotrana and some other taxa described is considered. The different patterns of the leaf trace of simple and compound tri- to unifoliolate leaves may prove to be of systematic value.     

Multivariate analysis of morphological and anatomical characters of Calophyllum (Calophyllaceae) in South America

Calophyllum (Calophyllaceae), previously placed in Clusiaceae, is easily recognizable by its opposite entire leaves with close parallel venation alternating with resin canals. However, distinction between species has been difficult, because of infraspecific variation in tepal and stamen number and resemblance among species that share similar habitats. Here, I report the results of multivariate analyses of morphological and anatomical characters for Calophyllum in South America, and provide a taxonomic treatment for the genus in South America, the first since that of Vesque in 1893. Thirteen preliminary morphogroups were identified. Thirty‐two morphological characters of the leaf, flower and fruit from 401 specimens, and 17 anatomical leaf characters from 45 specimens were measured and analysed using principal component analyses (PCAs) and discriminant analyses (DAs). PCAs were used to find groups and DAs were used to validate those PCAs that were potential groups. Two main subgroups were identified in the general analysis. Subgroup M1 has terete stems and smaller leaves and flowers than subgroup M2, which, instead, has quadrangular stems. Only subgroup M2 showed distinctive clusters in regional and local analyses. Distinctive clusters and morphological and anatomical characters helped us to recognize four species in South America, including a new species, Calophyllum pubescens sp. nov. . In addition, a new species, Calophyllum mesoamericanum sp. nov. , is described from Central America. © 2013 The Linnean Society of London,     

Leaf architecture and ecophysiology of an early basal eudicot from the Early Cretaceous of Spain

Iterophyllum lobatum gen. et sp. nov. is reported from the late Barremian lithographic limestones of Las Hoyas, Spain. It consists of a simple, petiolate leaf, with a pinnately lobed lamina. The dentate thickened margin bears chloranthoid‐like glands at lobe apices and sinuses. The venation is pinnate and craspedodromous, with three discernible vein orders. Based on the low regularity of vein course and angles and the low leaf rank, such a venation pattern may represent an early evolved leaf archetype in early basal eudicots. An acropetal leaf development mode in I. lobatum is similar to that in several living Papaveraceae. The leaf architecture and ecophysiology, particularly the vein widths and the glands, indicate that I. lobatum leaves were aerial. The plant grew close to water in the wetland terrestrial ecosystem of Las Hoyas. Iterophyllum lobatum might have been an opportunist species in early ecological succession stages after wildfires. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173 , 594–605.     

Comparative systematic study of colleters and stipules of Rhizophoraceae with implications for adaptation to challenging environments

Colleters are multicellular secretory structures found on various organs in flowering plants. Colleters on the adaxial sides of stipules have been hypothesized to play a role in protecting the developing shoot. Rhizophoraceae is a stipulate family with a broad distribution from mangrove to montane environments, which makes the family well suited for the examination of this hypothesis, but the colleters of Rhizophoraceae are not well known. We compared species from all three tribes of Rhizophoraceae, including five inland genera and all four mangrove genera. In all species, several to hundreds of colleters, sessile or stalked, arranged in rows aggregated in genus‐specific shapes, are found at the adaxial bases of open and closed stipules. Pellacalyx uniquely has additional colleters at the stipule margins. Colleters are all of the standard type, comprising a central axis of core parenchyma with large vacuoles and tannins, and an outer palisade‐like epidermis with organelles involved in secretory activity. An exception is Pellacalyx axillaris, in which colleters appear as extremely small epidermal protrusions. Kandelia obovata has a tracheary element in some colleters. Pellacalyx uniquely has an unusual fleshy outgrowth on the adaxial stipule base. We propose an evolutionary sequence in which Macarisia has plesiomorphic stipule and colleter traits and the mangrove Kandelia obovata with colleter vascular traces is most derived. Colleter and stipule structures are largely concordant with habitat and phylogeny, and show taxonomic value. The strong alignment of colleter and stipule patterns with habitat is suggestive that colleters have a protective function, although some components of these patterns may be phylogenetically determined. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172 , 449–464.     

Molecular evolution and diversification of the moss family Daltoniaceae (Hookeriales,Bryophyta) with emphasis on the unravelling of the phylogeny of Distichophyllum and its allies

Phylogenetic relationships in Daltoniaceae (～200 species in 14 genera) are inferred from nucleotide sequences from five genes, representing all genomic compartments, using parsimony, likelihood and Bayesian methods. Alternative classifications for Daltoniaceae have favoured traits from either sporophytes or gametophytes; phylogenetic transitions in gametophytic leaf limbidia and sporophytic exostome ornamentation were evaluated using ancestral state reconstruction to assess the levels of conflict between these generations. Elimbate leaves and the cross‐striate exostome are reconstructed as plesiomorphic states. Limbate leaves and papillose exostomes evolved at least two and six times, respectively, without reversals. The evolution of leaf limbidia is relatively conserved, but exostome ornamentation is highly homoplasious, indicating that superficial similarity in peristomes gives unreliable approximations of phylogenetic relatedness. Our phylogenetic analyses show that Achrophyllum and Calyptrochaeta are reciprocally monophyletic. Within core Daltoniaceae, relationships among taxa with elimbate leaves are generally well understood. However, taxa with limbate leaves form a monophyletic group, but resolved subclades correspond to biogeographical entities, rather than to traditional concepts of genera. Daltonia (～21 species), Distichophyllum (～100 species) and Leskeodon (～20 species) are polyphyletic. Seven nomenclatural changes are proposed here. As the current taxonomy of Daltoniaceae lacks phylogenetic consistency, critical generic revisions are needed. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, ?? , ??–??.