Lamina Anatomy Research Articles

Leaf Anatomy Structure of Codiaeum variegatum (L.) Rumph. ex A. Juss Cultivars

Codiaeum variegatum (L.) Rumph. ex a. Juss is a common ornamental plant with a high variation of leaves shape and colour. This study aimed to analyze the leaves’ anatomy and the phenetic relationship between eight cultivars of C. variegatum which were defined by the differences in leaf morphology. The paraffin method prepared the transversal section of leaves, and anatomical characters were converted into binary data to calculate the similarity coefficient which was analyzed by Numerical Taxonomy System (NTSYS) 2.1 version. Leaves of eight cultivars of C. variegatum are varied in the anatomical structure of the primary vein and lamina. The eight cultivars of C. variegatum were clustered into four. The variations were found in 19 primary vein and lamina anatomy characteristics and the similarity coefficient is up to 0.59 between all cultivars. It can be concluded that the combination of leaf anatomical structures and midrib anatomical characters have notable taxonomic implications for future research.

Two centuries from species discovery to diagnostic characters: molecular and morphological evidence for narrower species limits in the widespread SW Australian Anarthria gracilis complex (Restionaceae s.l./Anarthriaceae, Poales).

BackgroundThe extreme southwest of Australia is a biodiversity hotspot region that has a Mediterranean-type climate and numerous endemic plant and animal species, many of which remain to be properly delimited. We refine species limits in Anarthria, a Western Australian endemic genus characterised by the occurrence of the greatest number of plesiomorphic character states in the restiid clade of Poales. In contrast to many other groups of wind-pollinated Australian Poales, Anarthria was traditionally viewed as having well-established species limits. All six currently recognised species, which are conspicuous members of some Western Australian plant communities, were described in the first half of the 19th century. They are traditionally distinguished from each other mainly using quantitative characters.MethodsWe examined extensive existing herbarium specimens and made new collections of Anarthria in nature. Scanning electron microscopy and light microscopy were used to study leaf micromorphology. Molecular diversity of Anarthria was examined using a plastid (trnL-F) and a low-copy nuclear marker (at103). This is the first study of species-level molecular diversity in the restiid clade using a nuclear marker.ResultsMaterial historically classified as Anarthria gracilis R.Br. actually belongs to three distinct species, A. gracilis s.str., A. grandiflora Nees and A. dioica (Steud.) C.I.Fomichev, each of which forms a well-supported clade in phylogenetic analyses. Both segregate species were described in the first half of the 19th century but not recognised as such in subsequent taxonomic accounts. Anarthria dioica was first collected in 1826, then wrongly interpreted as a species of Juncus (Juncaceae) and described as Juncus dioicus. We provide a formal transfer of the name to Anarthria and for the first time report its clear and qualitative diagnostic characters: an extremely short leaf ligule and distinctive pattern of leaf epidermal micromorphology. A long ligule is present in A. gracilis s.str. and A. grandiflora. These species differ from each other in leaf lamina morphology and anatomy and have mostly non-overlapping distribution ranges. The narrower definition of species provides a basis for future phylogeographic analyses in Anarthria. Our study highlights a need for more extensive use of nuclear DNA markers in Restionaceae. The use of the low copy nuclear marker at103 allowed a clade comprising all three ligulate species of Anarthria to be recognised. The ligule character is used here for the first time in the taxonomy of Anarthria and merits special attention in studies of other restiids. In general, our study uncovered a superficially hidden but, in reality, conspicuous diversity in a common group of wind-pollinated plants in the southwest of Western Australia.

Anatomical investigations of the Turkish critically endangered species: Achillea sivasica Çelik et Akpulat (Asteraceae)

In this study, the root, stem, leaf midrib and leaf lamina anatomy and achene micromorphology of the Turkish critically endangered endemic Achillea sivasica were investigated for the first time. In this study, the root was found in late primary growth and in early secondary growth stage. It has a large cortex layer consisting of 12-16 cell rows beneath the periderm. Secretory ducts formed by 5-12 secretory cells embedded in the cortex and located near the vascular bundle were found at the root, which was in the early stage of secondary development. The stem was circular-pentagonal in cross-section. There was lamellar collenchyma beneath epidermis of pentagon corners, and cortex parenchyma between corners. Secretory ducts located near the phloem, between the cortex and endodermis on the interfascicular region, were also observed. An endodermis layer was evident and its cells have indentations and protrusions where they touch adjacent endodermis cells, which strengthens the connection between them. In addition, casparian strips were conspicuous in many endodermis cells. The leaf midrib area had a triangular cross section. There were secretory ducts, consisting of 4-5 secretory cells observed on both sides of the sclerenchymatous fibers that accompany the xylem. The leaf lamina was amphistomatic and stomata type was anomocytic. Mesophyll layer was equifacial. There was a large secretory duct and its diameter is bigger than the nearest main lamina vascular bundle. Achene shape of A. sivasica was lanceolate-oblong and its surface was ribbed and glabrous.

Morphological, phytochemical and biological studies of Morus L. (Moraceae)

Morus L., a multipurpose agro-forestry plant, belongs to tribe Moreae (family Moraceae), has high economical and medicinal values. There are a lot of conflictions regarding the number of Morus spp. as a result of producing new varieties and hybrid individuals. Macro & micromorphological characters viz. whole plant, ab- & adaxial lamina epidermis using SEM, lamina & petiole anatomy, phytochemical screening and quantitative analysis of the polyphenol and flavonoid contents of seven Morus taxa were investigated as well as the survey of polyphenols and flavonoids qualitatively in M. alba, M. macroura and M. nigra using HPLC analysis. The biological studies carried on one selected taxon M. alba (as it is the most prominent of these species). The specific objective of the present study is to throw light on the morpho-anatomical characters of Morus spp. in delamination among them, to screen the phytochemical constituents of aerial parts and fruits as well as to study the in vitro anti-oxidant, cytotoxicity and anti-inflammatory activities of M. alba. The obtained results highlighted that the macro & micromorphological characters were considered diagnostic at specific level viz. fruit size and color, lamina size, shape, margin, apex, base and leaf type, outline of petiole, ground system, aspect and number of vascular bundles, crystals types and phytoliths’ shapes and sizes. The results of UV spectrophotometric analysis indicated that M. nigra cv. Al-taify had the highest content of flavonoids and polyphenols. The polar extract of M. alba showed potential inhibitory effect of induced inflammation and considerable effect on scavenging of free radicals and showed mild growth inhibition of cancer cell lines.

Phenetic analysis on some taxa of Crassulaceae DC. based on morphological and molecular criteria

The Crassulaceae faced many arguments considering its taxonomic relationship with the nearby families. The present study based on the examination of 23 taxa (22 representing Crassulaceae and Saxifraga sarmentosa representing Saxifragaceae as an outgroup). The macro- and micromorphological characters of the studied taxa viz. stem, lamina anatomy, lamina epidermal characteristics were investigated by the aid of LM and SEM as well as molecular characters. All the obtained macr-, and micrmorphological characters as well as molecular data are subjected to PAST program Version 3.16. The aim of the present study is to integrate the morphological and molecular taxonomic tools to produce a more realistic and accurate phenogram in expressing the true relationships among the taxa under investigation and give point of view in classification systems of the family. The macro- and micromorphological characters are summarized in cumulative tables and illustrated colored plates, discussed and compared with other studies and previous taxonomic systems. The molecular data sequence and accession number were upload on gene bank data base. The obtained phenogram segregates the 22 of Crassulaceae OTU’s into into two main groups and three subgroups (a1, a2 and a3) that correspond to the three tribes (Sedeae, umbiliceae and Kalanchoeae) respectively.

Anatomical considerations of C2 lamina for the placement of translaminar screw: a review of the literature.

The thorough knowledge of C2 lamina anatomy is essential for the avoidance of complications during screw fixation. We performed a review of the literature, aiming to detect what was found about anatomical feasibility of C2 translaminar fixation in different populations, along with possible recommendations for the avoidance of complications, and to detect whether factors such as race or gender could influence axis lamina anatomy and fixation feasibility. We performed a search in PubMed and Cochrane database of systematic reviews for studies which correlated axis lamina anatomy with fixation feasibility. We extracted data concerning measurements on C2 lamina, the methods and conclusions of the studies. Twenty-six studies met our inclusion criteria. The studies mainly focused on Asian populations. Male gender was generally related to larger anatomical parameters of C2 lamina. The use of a C2 translaminar screw with a diameter of 3.5mm was generally feasible, even in children, but there was disagreement about risk of vertebral artery injury. Computed tomography was most frequently recommended preoperatively. Three-dimensional reconstruction was suggested by some authors. C2 lamina anatomy generally permitted screw fixation in most studies, but there was disagreement about risk of vertebral artery injury. Preoperative computed tomography was generally recommended, while, according to some authors, three-dimensional reconstruction could be essential. However, there is a relative lack of studies about non-Asian populations. More research could further illustrate the anatomy of C2 lamina, clarify the safety of axis fixation for more populations and perhaps modify preoperative imaging protocols.

Butia capitata (Mart.) Becc. lamina anatomy as a tool for taxonomic distinction from B. odorata (Barb. Rodr.) Noblick comb. nov (Arecaceae).

The distinction between Butia capitata and B. odorata is based only on a few morphological characteristics, therefore there is a need for additional studies for supporting the separation of the species. As lamina anatomy characteristics are relevant in circumscribing Arecaceae taxa, this work aimed to describe B. capitata lamina anatomy and compare it with B. odorata. Samples from the middle portion of the pinnae were collected and processed in accordance with standard plant anatomy techniques. The epidermis is uniseriate and composed of a thick cuticle and epicuticular waxes into like hooked filaments. The subsidiary cells that arch over the guard cells are located at the hypodermis. The mesophyll is isobilateral and compact. The vascular bundles are collateral with a sclerenchymatic sheath extension that reaches the hypodermis. The stegmata cells have spherical and druse-like silica bodies. The midrib faces the adaxial surface with a thick fibrous layer surrounding the vascular bundles adjacent to the chlorenchyma. The stratified expansion tissue is on the abaxial surface, within the boundary between the mesophyll and midrib. Raphides are only found in B. capitata. Small bundles of the midrib fully surround the fibrous cylinder only in B. odorata. These characteristics are diagnostic and useful for supporting the proposed separation.

Comparative Leaves Anatomical Studies of Bouea, Mangifera and Spondias (Anacardiaceae) in Malaysia

Leaves anatomy of two species of Bouea, 11species of Mangifera and two species of Spondias were studied in order to see the differences in stomata type, petiole, midrib and lamina anatomy and leaf venation. This study aims to use anatomical characters for species and genus identification. Common characters observed were the absence of trichomes, closed vascular bundles, uniseriate epidermal layers, resin canal in parenchyma cells, anticline wall patterns and druses crystals in leaf lamina transverse sections. All species displayed closed vascular bundles except Mangifera pajang which showed a combination of medullary vascular bundles. Uniseriate epidermal layer was observed in all species. All the species showed straight-wavy anticlinal walls. Druses crystals were found in the parenchyma cells of all the species. Four types of stomata were observed namely anomocytic, anisocytic, staurocytic and diacytic. Anomocytic, anisocytic and staurocytic stomata were observed in Mangifera, diacytic in Bouea and anomocytic in Spondias.

The anatomy of palms (Arecaceae–Palmae)

Palms are without doubt one of the most important plant families from a human perspective and they are vital to both the ecological and economic wellbeing of the world's tropical regions. Understanding how they function is therefore an important challenge to palm biologists, who will be gladdened by the appearance of this new and important textbook by Tomlinson, Horn and Fisher. The anatomy of palms does what it says on the cover: it provides the reader with an in-depth survey of anatomical diversity within the Arecaceae. This information is given a phylogenetic focus by the inclusion, as a backdrop to the anatomical data, of the now well-established genus-level phylogeny of the family. Palms are a readily recognisable group of plants. Two of their typical characteristics are of particular relevance here: firstly, their large size raises problems for microscopy studies and necessitates, as pointed out by the authors, a ‘seemingly reductionist’ approach involving ‘small samples from relatively standard regions of the plant’. Secondly, palm tissues are often very fibrous, with strong lignification and frequent occurrence of silica bodies, thus making them difficult to fix and section. As can be expected from a group of established leaders in the field of palm anatomy, the authors have tackled these obstacles with great success. Many of the images in the book were obtained from unembedded material and were prepared specially for this publication. The book consists of 276 pages in total and is a work of striking beauty, containing around 800 photos, the vast majority in colour. It is structured into various sections: a short chapter on the anatomical methods used; a brief overview of palm biology; chapters on the structure of the lamina, leaf axis, stem, root and vascular tissues; then an overview of anatomical evolution in palms. The remaining (and greater) part of the book is devoted to the discussion of the anatomical features of the palm family in a phylogenetic context. Each of the currently recognised 183 palm genera is dealt with. The internal structure of all vegetative organs of palms is reviewed, with special emphasis on lamina anatomy. Taxonomic keys based on anatomical characters are provided for groups at different levels in the family. Thus keys are given for some genera (e.g. Hyophorbe), while others relate to subtribes (e.g. Attaleinae) or tribes (e.g. Ceroxyleae). Although the authors emphasise in the preface that the ‘incompleteness’ of this work should be recognised, it will be immediately apparent to most readers that this is a titanic work that will serve as a reference to the palm community for many years to come. The anatomy of palms will be a ‘must have’ reference book, not only for palm biologists, but also for the wider community of structural plant biologists interested in the diversity and evolution of anatomical characters. It will also be an ideal complement to The structural biology of palms, another essential but more general work published earlier by P. Barry Tomlinson (1990), the latter now being available as a ‘print on demand’ version.

Seasonal variation of fixed and volatile oil percentage of four Eucalyptus spp. related to lamina anatomy

This experiment was conducted during the four seasons: Spring, summer, autumn and winter of two successive annual cycles; 2008/2009 and 2009/2010 (starting from May 2008). Four Eucalyptus species were under investigation; Eucalyptus camaldulensis Dehnh., Eucalyptus cinerea F. Muell. ex Bentham, Eucalyptus citriodora Hook. and Eucalyptus globulus Labill. Seasonal variations in the amount of fixed and volatile oils in Eucalyptus spp. matured leaves were investigated. It was determined that the amount of total lipids and essential oils significantly varied by the seasons (P < 0.01). The amount of total lipids in Eucalyptus spp. reached its peak mostly in spring. But the amounts of essential oils in different species were determined to be higher in summer, autumn and spring seasons, than in winter. Furthermore, the amount of total lipids and essential oils was higher in E. camaldulensis and E. cinerea than in other species. The anatomical investigation in the four studied Eucalyptus species, in relation to lipids percentage indicated that, the best lipids percentage amounts in this study were exhibited in E. cinerea and E. camaldulensis, for spring and winter; and were in agreement with these species highest lamina thickness. In general, fluctuation in lipids percentage is more correlated to the internal structure of lamina (duct average diameter, ducts total numbers, and open ducts numbers) in the same season; whereas, among seasons, it is thought that metabolism contributed more greatly. Cuticle thickness is true correspondence to seasonal environmental fluctuation, since it increases in all species, by shifting up from spring to summer then decrease to winter. Essential oils secretion which coincided with lipids percentage may be due to environmental stress influence over metabolism rather than structural adaptation. Key words: Eucalyptus, seasons, fixed and volatile oils, lamina, anatomy, glands.

Evolution of lamina anatomy in the palm family (Arecaceae)

The unique properties of tree building in Arecaceae strongly constrain their architectural lability. Potentially compensating for this limitation, the extensive diversification of leaf anatomical structure within palms involves many characters whose alternate states may confer disparate mechanical or physiological capabilities. In the context of a recent global palm phylogeny, we analyzed the evolution of 10 such lamina anatomical characters and leaf morphology of 161 genera, conducting parsimony and maximum likelihood ancestral state reconstructions, as well as tests of correlated evolution. Lamina morphology evolves independently from anatomy. Although many characters do optimize as synapomorphic for major clades, anatomical evolution is highly homoplasious. Nevertheless, it is not random: analyses indicate the recurrent evolution of different cohorts of correlated character states. Notable are two surface layer (epidermis and hypodermis) types: (1) a parallel-laminated type of rectangular epidermal cells with sinuous anticlinal walls, with fibers present in the hypodermis and (2) a cross-laminated type of hexagonal cells in both layers. Correlated with the cross-laminated type is a remarkable decrease in the volume fraction of fibers, accompanied by changes in the architecture and sheath cell type of the transverse veins. We discuss these and other major patterns of anatomical evolution in relation to their biomechanical and ecophysiological significance.

A new Coryphoid palm genus from Madagascar

Tahina J.Dransf. & Rakotoarinivo, gen. nov. (Arecaceae) is described as a new genus from north-western Madagascar, with a single species T. spectabilis J.Dransf. & Rakotoarinivo, sp. nov.Tahina is included within tribe Chuniophoeniceae of subfamily Coryphoideae, based on the strictly tubular imbricate rachilla bracts, the flowers grouped in cincinni with tubular bracteoles, and the stalk-like base to the corolla. This position is corroborated by evidence from plastid DNA. Lamina anatomy is discussed in detail, and similarities with and differences from the other members of Chuniophoeniceae are discussed. Based on the ecological characteristics of the single locality, predictions are made on where else it may occur in Madagascar. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 156, 79–91.

A Monograph of Phoenix L. (Palmae: Coryphoideae)

Summary. Thirteen species are treated including one new species from the Andaman Islands, IP andamanensis, and two varieties within R loureiri, var. loureiri and var. humilis. Species limits and distributions are defined, and aspects of morphology and lamina anatomy are examined in relation to ecology. Systematic analyses of the genus combine data from studies of morphology and lamina anatomy with DNA sequence data of the 5S spacer region (nuclear ribosomal DNA). The origin of P dactylifera is discussed in the light of the results of the systematic analysis.

PARAVEINAL MESOPHYLL IN CALLIANDRA TWEEDII AND C. EMARGINATA (LEGUMINOSAE; MIMOSOIDEAE).

Paraveinal mesophyll (PVM) in Leguminosae, subfamily Mimosoideae, was first reported in 1894 but never described in detail before now. We cleared, and sectioned in resin, leaflets of Calliandra tweedii and C. emarginata (Tribe Ingeae). Lamina anatomy in both species is very similar: one palisade layer, two to three spongy layers, and the horizontal veinal network with its interconnected PVM in between. PVM is a unistratose cellular lacework extending between veins and attached medianly along each flank of all veins. PVM cells have a normal complement of typical chloroplasts similar to other mesophyll cells. Most veins are ensheathed by fibers except for an extended lateral slit along each flank where the PVM is attached; a parenchymatous bundle sheath is therefore lacking. All vein endings lack phloem, although the tracheary elements of some vein endings are flanked by one or two long, slender, seemingly undifferentiated cells. Occasional small gaps occur between the PVM cell wall and adjacent tracheary elements, which expose xylem directly to mesophyll intercellular space. PVM anatomy of Calliandra, including its physical relationship to the various vein orders, differs in some important respects from PVM of the few other leguminous and nonleguminous species studied anatomically in any detail.

Paraveinal Mesophyll in Calliandra tweedii and C. emarginata (Leguminosae; Mimosoideae)

Paraveinal mesophyll (PVM) in Leguminosae, subfamily Mimosoideae, was first reported in 1894 but never described in detail before now. We cleared, and sectioned in resin, leaflets of Calliandra tweedii and C. emarginata (Tribe Ingeae). Lamina anatomy in both species is very similar: one palisade layer, two to three spongy layers, and the horizontal veinal network with its interconnected PVM in between. PVM is a unistratose cellular lacework extending between veins and attached medianly along each flank of all veins. PVM cells have a normal complement of typical chloroplasts similar to other mesophyll cells. Most veins are ensheathed by fibers except for an extended lateral slit along each flank where the PVM is attached; a parenchymatous bundle sheath is therefore lacking. All vein endings lack phloem, although the tracheary elements of some vein endings are flanked by one or two long, slender, seemingly undifferentiated cells. Occasional small gaps occur between the PVM cell wall and adjacent tracheary elements, which expose xylem directly to mesophyll intercellular space. PVM anatomy of Calliandra, including its physical relationship to the various vein orders, differs in some important respects from PVM of the few other leguminous and nonleguminous species studied anatomically in any detail.

Lamina architecture and anatomy in the Heliconiaceae and Musaceae (Zingiberales)

Lamina size, thickness, venation, and anatomy are studied in 15 species of Heliconia (Heliconiaceae), 3 species of Musa, and 1 of Ensete (Musaceae). The most typical laminas of these genera are large and oblong and have an acute or irregular apex and an asymmetrical cordate base. The laminar veins are parallel and are oriented essentially perpendicular to the costa and the margin. However, there is considerable variation in lamina architecture in the Heliconiaceae. Thickness ranges considerably across the lamina, with considerable variation between species. The only pattern common to all species is that the blades are thinner at the margin than at the costa. The veins of the lamina occur in a number of size classes that are arranged into a repeating unit called a set. Set patterns are described for the species and families. Although the Heliconiaceae and Musaceae do not differ in general set pattern, variation in the Heliconiaceae tends toward simpler sets, whereas the Musaceae tends towards more complex sets. Lamina anatomy is similar to that reported in the literature for these families, with several notable exceptions. The Heliconiaceae and Musaceae may be distinguished by characteristics of their lamina anatomy and by the fact that Musaceae blades have an irregular apex. The value of these characters for taxonomic and cladistic analyses is discussed. Key words: leaves, plant anatomy, vasculature, Zingiberales, Musaceae, Heliconiaceae.

The structural biology of palms

Introduction - an appreciation of palms Phasic development in palms Embryo and seedling Establishment phase Mature vegetative phase Vascular anatomy of the stem Palm stem - mechanics, age determination, and hydraulics Vascular development Leaf Lamina anatomy The root Inflorescence Flower Fruit and seed Defences Relationships and origin of the Palmae Appendix: Synopsis of a classification of the palms Bibliography Index.

Leaf anatomy of alpine plants as related to altitudinal stress

Alopecurus gerardi, Poa alpina, and Carex curvula are spontaneous, perennial forage plants distributed in the high elevation (2300–3200 m) pasture lands of Piedmont and Valle d'Aosta (Italy). Sedum atratum is an annual succulent which grows at elevations up to 3200 m. The three monocotyledons have, in comparison with corresponding plants from the low‐land, peculiar organographic and anatomic structures such as curling leaf lamina, vascular bundle sheath layer with chloroplasts arranged in a centrifugal fashion, low stomatal density (stomata number/cm2: upper epidermis x̄= 0–11.9; lower epidermis x̄= 7.66–11.55), thick cuticles, as well as higher values of S (H2O; g/dm2; x̄= 0.6–0.32), Sm (H2O g/mg Chi.; x̄= 0.11–0.16), SLW (g f. wt/dm2; x̄= 0.86–1.36), but lower SLA values (cm2/g f. wt; x̄= 75.07–116.77). All these data are correlated to water stress. Even though the leaf lamina anatomy possesses some features typical of C4 plants, the presence of starch grains in the mesophyll chloroplasts indicates that these plants are probably C3 ones.In spite of high values of thylacoid grana/thylacoid intergrana ratios, typical of shade plants (mesophyll chloroplasts: x̄ up to 3.81; bundle sheath chloroplasts: x̄ up to 5.3), and Chi a/Chl b ratios (x̄ up to 4.23 in C. curvula), the apparent absence of peroxisomes seem to indicate a very efficient dark phase of photosynthesis. S. atratum, in comparison with the typical CAM succulents, which live in dryer and warmer habitats, has a higher values of stomatal density (upper epidermis, x̄= 2.59; lower epidermis, x̄= 3.15) and of SLA (x̄= 24.98), but lower S (x̄= 3.83), Sm (x̄= 1.19) and SLW (x̄= 4.15).

Systematic Anatomy of Cyclanthaceae (Monocotyledoneae)-An Overview

A recent survey of lamina and stem anatomy of Cyclanthaceae, including information from species that represent ca. 25% of the family, allows a comparison with Pandanaceae and Palmae, which have putative affinities with the Cyclanthaceae. The three families are readily distinguished by a number of discrete morphological and anatomical features. We present synopses and diagnostic keys with special emphasis on lamina anatomy. The subdivision of the Cyclanthaceae proposed by Harling is supported by anatomical evidence, but, because of anatomical similarities, related genera may not always be clearly separated solely by lamina anatomy. The Palmae are especially isolated. Their distinctive features include a closed tubular leaf base, silica bodies in specialized cells (stegmata), exclusively simple stem vascular bundles, and vessels (sometimes with simple perforation plates) in stem, leaf, and root. Pandanaceae are distinguished, among other features, by cubical crystal bodies, an open leaf base, compound stem bundles without basipetal fusion, and possible lack of vessels in stem and leaf. Cyclanthaceae have an open leaf sheath but lack both silica bodies and cubical crystals, and commonly have mucilage cavities and diverse structural features (laticifers, styloids, parenchyma-like dead cells, tannin-like star figures) that, however, are not ubiquitous. In stems, vessels with long scalariform perforation plates occur in Thoracocarpus. Compound stem bundles show basipetal fusion of a distinctive kind. Sympodial branching below a terminal inflorescence occurs in some Cyclanthaceae and especially in the Pandanaceae, but never in the Palmae. In contrast, features by which these three families are traditionally associated seem superficial.