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Leiothrix differs from other genera of Eriocaulaceae by having pistillate flowers with nectariferous and stigmatic branches that diverge at different heights on the style and staminate flowers with free or fused petals. To understand the ontogenetic processes that result in these morphological variations, we studied the development and floral vasculature in six species of the genus. In pistillate flowers, the nectariferous branches, which are in a carinal position, correspond to the apex of the carpels, whereas the stigmatic branches, in a commissural position, are formed by the marginal tissues of the carpels and initiate later than the nectariferous branches. The upper margins of the carpels elongate, forming a tubular structure that raises the stigmatic branches; the greater its development, the greater the distance between the stigmatic and nectariferous branches. In staminate flowers, the fusion of the petals appears to be post-genital in the median and apical portions and congenital in the more basal portion. Despite the differences in floral development, Leiothrix shares the same pattern of floral vasculature with other genera of Eriocaulaceae, exhibiting a central vascular plexus in the receptacle from which a single trace diverges for each sepal, petal and stamen. The staminodes are not vascularized. The dorsal carpellary bundles supply the nectariferous branches, but the ventral carpel bundles are reduced and are not involved in the supply of the ovules and stigmas. The differences in the height of insertion of the nectariferous branches are probably the result of selective pressure exerted by different groups of pollinating insects. Our hypothesis is that species in which the nectariferous branches are inserted below the stigmatic branches, and are therefore less accessible, exhibit a more specialized pollination system. The absence of nectariferous branches in L. angustifolia indicates secondary loss probably associated with spontaneous geitonogamy. [ABSTRACT FROM AUTHOR]

The floral anatomy and development of species belonging to all sections of Xyris (Xyris , Nematopus and Pomatoxyris) were investigated comparatively to elucidate gynoecium evolution in the genus, because placentation has been one of the key characters in recognizing its taxonomic sections. In species of section Pomatoxyris (axile placentation), the tricarpellate syncarpous ovary consists of a fertile synascidiate zone, whereas the symplicate zone is fertile only in its lower portion. In species of section Xyris (parietal placentation), the ovary has a short almost sterile synascidiate zone, whereas the more extensive symplicate zone is fertile. In species of section Nematopus (free-central or basal placentation), there is an extremely short and sterile trilocular, completely septate zone at the ovary base. Such differences are related to different patterns of gynoecium development. The ancestral character state reconstruction of placentation types shows that axile placentation is the most likely ancestral condition in Xyris , from which parietal and free-central placentation were derived by shortening of the septa during the evolution of the genus. Basal placentation evolved from free-central placentation and appeared independently several times in section Nematopus. Because the phylogenetic position of X. ptariana and X. teinosperma (section Nematopus) is unknown, either the axile placentation in these species is a reversal or highlights the need for a revised infrageneric classification. [ABSTRACT FROM AUTHOR]

Xyridaceae are represented in New Caledonia only by the genus Xyris , the description of which was last revised in the 1960s, and three endemic species were recognized there at that time, X. pancheri , X. neocaledonica and X. guillauminii. However, no specimens of X. guillauminii were reported from P or L, although some type material was present. In addition, most material was unidentified at the species level in international herbaria (up to 45% for the NOU herbarium), showing that the family had not been studied in the framework of the Flore de la Nouvelle-Calédonie. In total, 129 herbarium specimens were examined for an ascendant hierarchical classification and a principal coordinates analysis based on 18 morphological characters regarded as diagnostic at the species level (including six used in the original revision). The analyses revealed three well-delimited groups that potentially correspond to species-level units. A sub-sampling of 21 specimens, representative of these three groups, was studied anatomically (leaf cross-sections) and by scanning electron microscopy (leaf surface and seeds) and provided ten additional characters. This additional dataset validated the taxonomy in three species-level units. The resulting entities were then compared with nomenclatural types, which showed that the first corresponded to X. neocaledonica , the second represents a well-delimited, undescribed species, and the third includes types of both X. pancheri and X. guillauminii , this last being in need of synonymization. The findings of the present study provide a basis for undertaking a taxonomic revision of Xyris in New Caledonia, including the description of the new species. All New Caledonian species have an axile placentation and a trilocular ovary, so they belong to Xyris section Pomatoxyris , which is no longer endemic to Australia. [ABSTRACT FROM AUTHOR]

Subtribe Eleusininae (Chloridoideae, Poaceae) comprise 237 species with little morphological diversity in inflorescence structure. This diversity may be explained by an evolution from complex (pyramidal, highly branched) to simpler (digitate, barely branched) morphologies. However, only mature specimens have been studied; the developmental analyses of the inflorescences are rare. We analysed the inflorescence, spikelet and flower development of 17 species of Eleusininae using scanning electron microscopy. In the early stages of the transition to flowering of the studied species, the inflorescence meristem elongates initiating primary branches acropetally. The differentiation of these branches along the main axis is either basipetal or amphipetal. Although the initiation of secondary branches along primary branches may be acropetal or amphipetal, their differentiation follows an amphipetal direction. The florets in spikelets are initiated acropetally. We found abnormal orientation of stamens and gynoecium in florets of Leptochloa chloridiformis. The analysis of the ontogeny has enriched current knowledge of inflorescences in the subtribe. In addition, the developmental patterns revealed the existence of more than one developmental pattern leading to similar mature inflorescence forms. The results will support future efforts on postulating trends of developmental patterns across Poaceae. [ABSTRACT FROM AUTHOR]

Aechmea (Bromeliaceae) is a large genus with controversial systematics and distinct flower shapes and pollinators. We explored floral anatomy and development in two Aechmea spp. belonging to different subgenera to contribute useful information on reproductive biology and taxonomy. We examined floral buds using scanning electron and light microscopy to characterize the development of septal nectaries, petal appendages, ovules, stamens and carpels. In A. gamosepala, we confirmed that the petal appendages develop late, whereas in A. correia-araujoi they develop earlier during floral development. Petal appendage formation included positional changes, possibly affecting floral attributes and visitation by insects, rather than vertebrates. Nectar is released through three basal orifices distally on the ovary, and here we document the link between the nectary region, through discrete canals, upward to the conduplicate lobes of the wet stigma. Improved understanding of the floral development and morphology of Aechmea may help to explain the existence of polymorphic flowers in this genus and may have implications for studies on interactions with pollinators and systematics. [ABSTRACT FROM AUTHOR]

Leaf teeth are projections on the leaf blade margin. They are structurally variable, with characters that are important for taxonomy and phylogeny, but there is a paucity of information on the anatomy of these structures and little understanding of the features and their functions. Here we describe and compare the leaf tooth anatomy of 47 eudicot species. Toothed margin samples from leaves at different developmental stages were collected, fixed and studied under light and scanning electron microscopy. We identified eight leaf tooth morphotypes, six of which occurred with glands. Hydathodes were the most common glands, being found in 11 species; colleters were found in ten species and extrafloral nectaries were found in two species. Cunonioid teeth either devoid of glands or associated with hydathodes were found in Lamiales, Asterales and Apiales. Dillenioid teeth associated with hydathodes were found in Dilleniales. Spinose teeth associated with colleters were found in Aquifoliales. In rosids, we found begonioid, malvoid, theoid, urticoid and violoid teeth, which may be associated with either colleters or nectaries or lack an associated gland. For each family studied, there was only one type of association between gland and tooth, demonstrating the systematic potential of these glands in eudicots. [ABSTRACT FROM AUTHOR]

In Bromeliaceae, fruit type and seed morphology have been used to distinguish the subfamilies. We studied seed and fruit development of three species of Bromelioideae (Aechmea bromeliifolia , Billbergia distachia and Neoregelia bahiana) relating seed characters to fruit structure. Aechmea bromeliifolia has few ovules per locule inserted within the apical portion of the ovary and the seeds are larger, with a long chalazal appendage, growing towards the fruit base. In B. distachia and N. bahiana , the ovules are numerous and subapically to centrally inserted in the ovary; the seeds are smaller, with a radial disposition, and the chalazal appendages are short (B. distachia) or absent (N. bahiana). The chalazal appendages grow during seed development, and thus their presence/length may be related to the number of ovules/seeds per locule and to the disposition of the ovules inside the locules. The fruits are berries, and juiciness is promoted by mesocarp cells and by substances secreted inside the locules by the placental obturator at later stages of fruit development. These fruit and seed features are strategies for zoochory and provide evidence that each species studied is dispersed by a different type of animal. [ABSTRACT FROM AUTHOR]

Nectar production dynamics can show inter- and intraspecific variation, which can be associated with environmental and ecological factors and with the ultrastructural diversity of the floral nectary. In this context, we recorded nectar production dynamics from a morphofunctional perspective using the hummingbird-pollinated Billbergia distachia (Bromeliaceae). The scale-throated hermit Phaethornis eurynome was the only floral visitor observed, indicating a specialized pollination system. Nectar production showed significant differences between day and night, and the periods of major pollinator activity and nectar secretion were synchronous. The ultrastructural features of the nectary showed some evidence of nectar reabsorption in flowers at night, and it can be inferred that this process may be a key factor in the nocturnal pause in nectar production. In this way, nectary morphoanatomy, nectar traits and an energy-saving mechanism through nectar reabsorption contribute to the well-established relationship between B. distachia and P. eurynome. [ABSTRACT FROM AUTHOR]

Morpho-anatomical studies of fruits are scarce in monocotyledons and particularly for the Brazilian species of Velloziaceae, a small family of monocots characteristic of the campo rupestre vegetation of Brazil. The main fruit types found in Velloziaceae are poricidal and loculicidal capsules, but capsule morphology is variable, which has led to discrepancies regarding fruit descriptions and terminology. In this study, we aimed to analyse fruit development in Brazilian Velloziaceae to obtain a better understanding of capsule dehiscence and to elucidate and describe in detail the fruit types occurring in the family. Based on our results, we discuss the terminology used to describe capsules of some species, e.g. capsules of Vellozia minima and V. epidendroides , previously classified as poricidal, should be called apical loculicidal, as they form three slits on the uppermost part of each carpel that are prevented from extending downwards by the precocious lignification of the pericarp. Capsules of Barbacenia purpurea , B. riparia and B. plantaginea have been classified using various terms, but they fit the definition of fissuricidal capsule and should be classified as such. We also propose an improved analysis for the character 'fruit type', previously used in phylogenetic reconstructions of Velloziaceae. We changed some states following the fruit reclassification proposed here and added a new state, 'capsule opening through lateral irregular aperture', to the character. Additionally, eight new phylogenetic characters derived from ovary and fruit characteristics are suggested. [ABSTRACT FROM AUTHOR]

Anarthria, Lyginia and Hopkinsia, endemic to south-western Western Australia, differ from the rest of Restionaceae sensu APG IV in the presence of dithecal rather than monothecal anthers. Dithecal and monothecal Restionaceae form two well-supported sister clades in molecular phylogenetic trees, but shared morphological features of Anarthria, Lyginia and Hopkinsia known so far are either symplesiomorphies (e.g. anther structure) or are characters that are homoplastic in monocots (e.g. absence of silica in culms). The taxonomic placement of the three genera has been controversial during the 20th century, including the idea of recognizing three monogeneric families. As comparative morphological data covering all three genera are limited, we provide a study of female flower structure and development in this group. This is the first developmental study of dithecal Restionaceae that uses scanning electron microscopy. With many more investigated characters, like earlier studies, we found no potential synapomorphies for the dithecal clade. However, we found the first morphological support for the conclusion from molecular data of a sister relationship between Hopkinsia and Lyginia. They share ovules with length not exceeding the width and the micropyle oriented towards the dorsal side of the carpel, which is probably a synapomorphy. Some other characters shared by the two genera could be plesiomorphic, such as inner whorl tepals that are shorter than the gynoecium throughout development. Contrary to some earlier reports, female flowers of all three genera are arranged in spikelets and do not have bracteoles. These characters are thus conserved across the restiid and graminid clades. The gynoecium of Hopkinsia is unicarpellate and not pseudomonomerous. Gynoecia with a single fertile ovule appeared several times and through different morphological pathways in the evolution of wind-pollinated Poales. [ABSTRACT FROM AUTHOR]

Inflorescence morphology in Poaceae subtribes Hilariinae, Monanthochloinae, Boutelouinae, Scleropogoninae and Muhlenbergiinae (Cynodonteae, Chloridoideae) has been revisited recently, but inflorescence development remains largely unexplored. The aim of this study is to contribute additional information on the development of inflorescences in Cynodonteae by generating data on Distichlis, Bouteloua, Munroa, Erioneuron and Muhlenbergia and to compare them with results for other grasses. Using scanning electron microscopy images, we identified common developmental patterns among grasses and described developmental novelties for Bouteloua, Distichlis and Muhlenbergia. Novel developmental features are: the amphipetal initiation of second-order branches along the inflorescence of B. curtipendula, the elongation of the internodes of the inflorescence branches before floral development in M. asperifolius and 'Type II' unisexual flowers in D. acerosa. Variable traits among studied species are: inflorescence symmetry, direction of branch and spikelet initiation and differentiation, number of developing stamens, glume developmental patterns and timing of the arrest of gynoecium development during the formation of unisexual flowers. Our results allow us to postulate that a delicate balance of phytohormones may direct early development of grass inflorescence branching system by controlling direction of first-order branch differentiation. The approach used here provides a link between definitive structures and the underlying genetics. [ABSTRACT FROM AUTHOR]

Carpels and ovules have been differently interpreted over the past two centuries. In this review, some of these interpretations are highlighted, with particular emphasis on the current situation. Ovules are part of and are enclosed in carpels in all living angiosperms. Living angiosperms are monophyletic, and the evolutionary association between ovules and the leaf-like part, the carpel wall, had taken place at or before the time the clade of extant angiosperms was established. From what we know at present, there are no 'cauline' ovules in extant angiosperms. Developmentally, carpel walls and ovules are not always synchronous across all extant angiosperms. In early development ovules may be relatively precocious or relatively late compared with carpel walls. They are late in early-diverging angiosperms (ANITA grade, magnoliids, some early-diverging eudicots) but precocious in some more derived groups (e.g. some Caryophyllales and Primulaceae). Carpel primordia have a certain depth in the floral apex, and the entire activated area of a carpel primordium may be several cell layers thick. Thus, the carpel is 'embedded' or 'rooted' within the remaining floral apex. The parts of a carpel develop at different times in carpel ontogeny and probably evolved at different times on the line leading to the angiosperms, which needs to be considered in interpretations. Carpel development depends on a complex genetic network, which increased stepwise over evolutionary time and contains hundreds of genes revealed in molecular developmental biology. The evolutionary history of such networks in carpel walls and ovules is unlikely to be easily disentangled, as most of these genes are not transcription factors. [ABSTRACT FROM AUTHOR]

The flowers of most Anacardiaceae have a floral nectary disk producing nectar rich in sugars. However, a recent study demonstrated that their nectaries might also produce other substances, including lipids and phenolic compounds. To explore the diversity of floral nectary production and (ultra)structure, and their potential for the systematics of Anacardiaceae, we studied seven genera and 13 species from the two subfamilies. We used spectrophotometry to identify sugars and histochemical tests for other substances, and electron and brightfield microscopy to study nectary (ultra)structure and secretory pathways. The composition of sugars and other substances can vary between closely related species and be more similar in species from different subfamilies, being of limited value for the systematics of the family. The general morphology and structure of the floral nectary and their secretory pathways appear to be conservative in the family, and, like the production of mixed secretions, they might be plesiomorphic. Three morphological types of floral nectaries are defined for the family: nectariferous disk with papillose (1) or smooth epidermis-type (2) and trichomatous-type (3). The secretions may be released both by granulocrine and eccrine mechanisms and exuded through nectarostomata or the cuticle. Further studies are needed to better understand their evolutionary and ecological implications in Anacardiaceae and other sapindalean lineages. [ABSTRACT FROM AUTHOR]

Extrafloral nectaries (EFNs) are particularly common in Fabaceae and their morphological diversity has proved taxonomically useful. However, their anatomy remains poorly investigated. In this study we analysed EFN anatomy in 12 species from ten genera of Fabaceae, using scanning electron microscopy and light microscopy. We found three main structural organizations of EFNs. (1) The 'embedded' EFNs (cryptic and externally non-visible) in Bauhinia forficata are secretory prickles in which nectar-secreting tissue is completely embedded within the prickle, representing a new kind of EFNs in plants. Among externally visible EFNs, (2) 'elevated' EFNs were found in seven species, including a Mimosa sp. belonging to a clade considered to lack EFNs, and (3) 'swollen-scar' EFNs derived from the abscission site of aborted buds were found in four species, including a new report in Galactia. In three species, we also found colleters anatomically similar to other colleters reported for Fabaceae. We discuss terminological issues in the (scarce) literature on EFN anatomy in Fabaceae, mainly due to incorrect interpretation of structures or misuse of existing terms. [ABSTRACT FROM AUTHOR]

Poaceae have been historically recognized by having homogeneous pollen grains. Most of the available studies have focused on species from open areas, and studies of tropical forest representatives of the family are scarce. Some studies have suggested pollination assisted by insects, contrasting with the traditional anemophily known for this family. We analysed pollen surface of 121 specimens belonging to 87 species, eight tribes and four subfamilies of Poaceae from Neotropical forests, based on scanning electron microscopy method. None of the analysed samples had ectexine without ornamentation. Four different patterns were observed, three mixed and one of them simple: microechinate-areolate (all tribes except Streptochaeteae; 71 species); microechinate-perfurate (12 species); microechinate-rugulate (exclusive to Olyreae, the tribe that includes the herbaceous bamboos and is confined to the understory in the Neotropical region; two species) and microechinate (Bambuseae and Streptochaeteae, two species). The present data broaden the knowledge on the palynology of Poaceae from tropical forests, because 14 genera and 75 species have the pollen surface characterized for the first time in this article. Patterns of ectexine variation, especially in subfamilies Anomochlooideae and Bambusoideae, include differences between and within genera, with application to taxonomic and evolutionary studies, and probably to other fields such as ecology, palaeobotany and reproductive biology in the family. [ABSTRACT FROM AUTHOR]

Oeceoclades maculata is the most successful invasive orchid in the Neotropics. The anatomy of the vegetative organs, peduncle and seeds of O. maculata was characterized to identify features of possible physiological and ecological importance. Plants from four locations in Soconusco, Chiapas, Mexico were selected. Transverse, longitudinal and paradermal sections of vegetative organs were observed using light and scanning electron microscopes. Oeceoclades maculata has amphistomatous leaves, with smooth and a thin to slightly thickened cuticle, a single-layered epidermis, a low density of small stomata (<13 mm-2) and numerous sunken glandular hairs on both surfaces. Mesophyll is homogeneous with abundant extravascular fibre bundles. The root has a multilayered velamen with abundant tilosomes. Numerous idioblasts with raphides were observed in leaves, pseudobulbs and roots. The seeds are fusiform, with smooth surfaces and transverse folds. Some of these traits link O. maculata with terrestrial and epiphytic habits and with xerophytic habits, with humid and high light intensity and humid environments. This combination of traits might be a key factor behind the success and expansion of O. maculata. Nonetheless, a detailed characterization of the microhabitats occupied, demography, reproductive strategies and mycorrhizal associations will be essential for understanding the behaviour of this invasive species and, if necessary, designing strategies for its control. [ABSTRACT FROM AUTHOR]

Water relations represent a pivotal nexus in plant biology due to the multiplicity of functions affected by water status. Hydraulic properties of plant parts are therefore likely to be relevant to evolutionary trends in many taxa. Bromeliaceae encompass a wealth of morphological, physiological and ecological variations and the geographical and bioclimatic range of the family is also extensive. The diversification of bromeliad lineages is known to be correlated with the origins of a suite of key innovations, many of which relate directly or indirectly to water relations. However, little information is known regarding the role of change in morphoanatomical and hydraulic traits in the evolutionary origins of the classical ecophysiological functional types in Bromeliaceae or how this role relates to the diversification of specific lineages. In this paper, I present a synthesis of the current knowledge on bromeliad water relations and a qualitative model of the evolution of relevant traits in the context of the functional types. I use this model to introduce a manifesto for a new research programme on the integrative biology and evolution of bromeliad water-use strategies. The need for a wide-ranging survey of morphoanatomical and hydraulic traits across Bromeliaceae is stressed, as this would provide extensive insight into structure-function relationships of relevance to the evolutionary history of bromeliads and, more generally, to the evolutionary physiology of flowering plants. [ABSTRACT FROM AUTHOR]

Tillandsioideae are composed of nine genera, most of these with unclear delimitation. The morphoanatomy of ovules and ovaries of 83 species from seven different genera was studied under light or scanning electron microscopy to contribute to the understanding of the relationships in the group. The nucellar epidermis and the parietal tissue showed a regular pattern for all Tillandsioideae. The presence of chalazal appendages, however, and their shape and size varied between the genera analysed. Most species had a single acuminate chalazal appendage. Catopsis was the only genus with multiple appendages. Guzmania and Racinaea lacked this structure. The integuments also presented a variable length and thickness among the different genera. The four to six layers of the outer integument were unique in Catopsis and the three cell layers condition in the inner integument of Tillandsia should be a retained feature as it was also observed in Catopsis. Many characteristics in ovule morphology presented here have great systematic value for distinguishing genera of the Tillandsioideae. In addition, these features can also help in the understanding of ovule evolution in Bromeliaceae as a whole. [ABSTRACT FROM AUTHOR]

The goal of this study was to analyse possible structural and ultrastructural differences between the secretory disk of male and functionally female flowers of Tapirira guianensis ( Anacardiaceae) at different developmental stages. Studies were carried out using light, scanning and transmission electron microscopy. Biochemical tests were employed to determine the proportion of sugars in the nectar of the floral morphotypes: they were found to be similar, both predominantly composed of sucrose. In addition to sugars, lipids and phenolic substances were identified in anthetic flowers; thus, the secretory disk is a mixed secretion gland, also called a sensu lato nectary. During anthesis, granulocrine and eccrine secretory mechanisms occur in both floral morphotypes. After anthesis and fertilization of the functionally female flower, only the lipophilic and phenolic secretion continues until the early stages of fruit development. An intrastaminal secretory disk that produces both nectar and lipids is reported for the first time in Anacardiaceae. © 2015 The Linnean Society of London, B otanical J ournal of the L innean S ociety, 2015, 179, 533-544. [ABSTRACT FROM AUTHOR]

The development of the ovule, fruit and seed of Xyris spp. was studied to assess the embryological characteristics of potential taxonomic usefulness. All of the studied species have (1) orthotropous, bitegmic and tenuinucellate ovules, with a micropyle formed by both the endostoma and exostoma; (2) a cuticle in the ovules and seeds between the nucellus/endosperm and the inner integument and between the inner and outer integuments; (3) helobial, starchy endosperm; (4) a reduced, campanulate and undifferentiated embryo; (5) a seed coat formed by a tanniferous endotegmen, endotesta with thick-walled cells and exotesta with thin-walled cells; and (6) a micropylar operculum formed from inner and outer integuments. The pericarp is composed of a mesocarp with cells containing starch grains and an endocarp and exocarp formed by cells with U-shaped thickened walls. The studied species differ in the embryo sac development, which can be of the Polygonum or Allium type, and in the pericarp, which can have larger cells in either endocarp or exocarp. The Allium-type embryo sac development was observed only in Xyris spp. within Xyridaceae. Xyris also differs from the other genera of Xyridaceae by the presence of orthotropous ovules and a seed coat formed by endotegmen, endotesta and exotesta, in agreement with the division of the family into Xyridoideae and Abolbodoideae. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 177, 619-628. [ABSTRACT FROM AUTHOR]

In Bromelioideae, the so-called nidularioid complex contains closely related genera, the circumscription of which has been problematic. The goal of this study was to describe the ovary and ovule anatomy of six species of the nidularioid complex belonging to Canistropsis, Canistrum, Edmundoa, Neoregelia, Nidularium and Wittrockia and to use these characters in a parsimony analysis of relationships. In all analysed species, schizogenous-type aerenchyma is present in the ovarian mesophyll. Edmundoa lindenii has trichomes on the ovary surface, and this character appears to be an autapomorphy for the species. Canistrum aurantiacum exhibited some autapomorphies, such as four cell layers in the outer integument, non-elongated cells in the nucellar epidermis and three or four layers of cells in the parietal tissue. In the remaining species of the complex, the presence of transversally orientated ovules and anticlinally elongated cells in the outer integument in the micropylar region appear to be synapomorphies. Canistrum aurantiacum shares few characters with the other species; these results and the latest phylogenetic analysis show that Canistrum spp. do not belong to the current nidularioid clade. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 177, 66-77. [ABSTRACT FROM AUTHOR]

In this study, we explore the features of microsporogenesis in Bromeliaceae and, in particular, the diversity and evolution of additional callose deposits. Cytokinesis type, cell wall formation, tetrad form and patterns of additional callose deposition after intersporal wall formation were studied in 12 species of Bromeliaceae (each from a different genus) presenting four different aperture patterns. Microsporogenesis is highly conserved, with successive cytokinesis, centrifugal cell plate formation and predominantly tetragonal and decussate tetrads, as in many monocots, but five different patterns of additional callose deposition were recorded. The optimization of patterns of additional callose deposition on the phylogeny of Bromeliaceae reveals convergences. Additional callose deposition is a variable and labile feature of microsporogenesis in Bromeliaceae and is linked, to some extent, to aperture pattern. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 176, 36-45. [ABSTRACT FROM AUTHOR]

Xyridaceae belongs to the xyrid clade of Poales, but the phylogenetic position of the xyrid families is only weakly supported. Xyridaceae is divided into two subfamilies and five genera, the relationships of which remain unclear. The development of the ovule, fruit and seed of Abolboda spp. was studied to identify characteristics of taxonomic and phylogenetic value. All of the studied species share anatropous, tenuinucellate and bitegmic ovules with a micropyle formed by the inner and outer integuments, megagametophyte development of the Polygonum type, seeds with a tanniferous hypostase, a helobial and starchy endosperm and an undifferentiated embryo, seed coat derived from both integuments with a tanniferous tegmen and a micropylar operculum, and fruits with a parenchymatous endocarp and mesocarp and a sclerenchymatous exocarp. Most of the ovule and seed characteristics described for Abolboda are also present in Xyris and may represent a pattern for the family. Abolboda is distinguished by the ovule type, endosperm formation and the number of layers in the seed coat, in agreement with its classification in Abolbodoideae. The following characteristics link Xyridaceae to Eriocaulaceae and Mayacaceae, supporting the xyrid clade: tenuinucellate, bitegmic ovules; seeds with a tanniferous hypostase, a starchy endosperm and an undifferentiated embryo; and a seed coat with a tanniferous tegmen. A micropylar operculum in the seeds of Abolboda is described for the first time here and may represent a synapomorphy for the xyrids. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 175, 144-154. [ABSTRACT FROM AUTHOR]

The Pampas in the southern Neotropics is a vast region with vegetation composed mainly of grasses, and it may be the least-studied ecosystem in southern South America. Contrary to what was thought until recently, this region is heterogeneous and harbours rich biodiversity and many endemic species; however, little is known about the current geographical distribution and evolution of its plants. Here, we present results from phylogeographical studies on two genera typical of open environments ( Petunia and Calibrachoa) that occur in both the Pampas and the high-altitude grasslands of southern Brazil. The rapid radiations of Petunia and Calibrachoa are examples of how strong selective pressures for different pollinators, coupled with adaptation to edaphic and climatic differences, may drive the diversification of plants in the Pampas. We also discuss factors that could have affected and driven the diversification and speciation of plants in this environment. Further studies, including some focusing on other taxa, are required to characterize the diversification of plant species in this region more accurately. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, ••, ••-••. [ABSTRACT FROM AUTHOR]

New comparative data are presented on the reproductive morphology and anatomy of two genera closely related to grasses, Flagellaria and Joinvillea, in which the flowers are superficially similar, especially in stamen morphology. This investigation demonstrates some anatomical differences between the two genera. For example, both genera depart from the 'typical' condition of tepal vasculature (three-traced outer tepals and one-traced inner tepals): in Flagellaria, each tepal receives a single vascular bundle and, in Joinvillea, each tepal is supplied by three vascular bundles. Joinvillea possesses supernumerary carpel bundles, as also found in the related family Ecdeiocoleaceae, but not in Flagellaria or grasses. In the anther, the tapetum degenerates early in Flagellaria, and is relatively persistent in Joinvillea, in which the pollen grains remain closely associated with the tapetum inside the anther locule, indicating a correlation between peripheral pollen (a feature that is common in grasses) and a persistent tapetum. This study highlights the presence of a pollen-tube transmitting tissue ( PTTT) or solid style in the gynoecium of Flagellaria, as also in many Poaceae, but not in Joinvillea or Ecdeiocoleaceae. We speculate that the presence of a PTTT could represent one of the factors that facilitated the subsequent evolution of the intimately connected gynoecia that characterize grasses. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 170, 393-404. [ABSTRACT FROM AUTHOR]

Floral morphology, anatomy and development are examined in X yris grandis ( Xyridaceae: Poales), with an emphasis on petal and sepal organogenesis and vasculature. Xyris is one of relatively few monocots in which the perianth is differentiated into two distinct whorls (here termed a double perianth). Xyris also possesses highly unusual perianth vasculature, with each petal being supplied by three veins and each sepal by a single vein, compared with the opposite condition in most other angiosperms with a double perianth. However, perianth development in X. grandis shows a pattern that is typical for monocots, with petals not markedly delayed in development. Xyris grandis is also remarkable for its petal aestivation, with each petal surrounding a stamen and two branches of adjacent staminodes, a type that is not reported for other Xyridaceae and may contribute to secondary pollen presentation. The results are discussed in the context of the diversity of a double perianth in monocots, compared with eudicots. Based on current data, our preferred hypothesis is that meristic differences are at least partly responsible for the apparently widespread occurrence of three-traced petals in monocots. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 170, 93-111. [ABSTRACT FROM AUTHOR]

Laeliinae are one of the most prominent orchid subtribes, with c. 40 genera and nearly 1500 species, and contain a disparate group of taxa with widely varying morphological features. There does not appear to be a complex of characters to which one can refer in order to delineate the subtribe as a whole. Thus, it was thought that vegetative anatomy might provide clues to the monophyly of the group. The microscopic structure of the leaves, stems and roots of representatives of most of the genera was studied. It was concluded that the anatomy lacks overall uniformity and that vegetative characters alone are insufficient to assess the relationships amongst the genera. The only nearly consistent anatomical feature was the abaxial row of fibre bundles in the leaves. Thus, anatomically, as well as morphologically, Laeliinae are a mixed bag. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160, 21–41. [ABSTRACT FROM AUTHOR]

The placement of Nartheciaceae within Dioscoreales is an unexpected result of molecular phylogenetics. Nartheciaceae generally differs from the rest of Dioscoreales in having less specialized flowers. Studies of this family are important to elucidate the evolutionary history of the order. Using scanning electron microscopy and light microscopy, we describe the details of the flower structure, initiation, and development in Metanarthecium, which is unique amongst Nartheciaceae in possessing both an almost superior ovary and septal nectaries. This is the first member of Dioscoreales for which all stages of organogenesis have been studied. Within Nartheciaceae, the presence/absence of septal nectaries and the position of the ovary are labile. The presence of post-genital fusion in the gynoecium correlates with the presence of septal nectaries. Septal nectary morphology is complicated in Metanarthecium, which raises the question of whether its floral structure (including superior ovary) is plesiomorphic within Dioscoreales. The septal nectaries of Metanarthecium show homoplastic similarity with those of Allium (Asparagales). The presence/absence of a compitum is probably variable at the infraspecific level in Metanarthecium as a result of alternative possibilities of post-genital fusion between ventral carpel margins. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158, 1–18. [ABSTRACT FROM AUTHOR]

The vegetative anatomy and morphology of 142 species of the angraecoid orchids (Angraecinae + Aerangidinae) and 18 species of Aeridinae were examined using light and scanning electron microscopy. Leafless members of Vandeae were of particular interest because of their unique growth habit. Leafy and leafless members of Angraecinae and Aerangidinae were examined and compared with specimens of Aeridinae. Vandeae were homogeneous in both leaf and root anatomy. A foliar hypodermis and fibre bundles were generally absent. Stegmata with spherical silica bodies were found associated with sclerenchyma and restricted to leaves in almost all specimens examined. Distinct inner tangential wall thickenings of the endovelamen occurred in several vandaceous genera. Exodermal proliferations and aeration units commonly occurred in both leafy and leafless Vandeae. Cladistic analyses of Angraecinae and Aerangidinae with members of Aeridinae and Polystachyinae as outgroups using 26 structural characters resulted in 20 000+ equally parsimonious trees. Vandeae formed the only well-supported clade in bootstrap analyses and were characterized by having a monopodial growth habit, spherical stegmata, loss of mucilage, and loss of tilosomes. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society, 2006, 151, 165–218. [ABSTRACT FROM AUTHOR]

On the basis of floral and vegetative morphology, 63 tropical American genera have been recognized within Maxillarieae. We were able to examine anatomical material of all subtribes, excluding Oncidiinae. Stegmata with conical silica bodies occur in leaves and stems of all subtribes excluding Ornithocephalinae, and pericyclic stegmata found in roots are characteristic of Lycastinae. Lycastinae and Maxillariinae are characterized by foliar glands, foliar fibre bundles and tilosomes. Endodermal cells are U-thickened in most Zygopetalinae; O-thickened in most Lycastinae, Ornithocephalinae and Telipogoninae; variously thickened in Maxillariinae; and thin-walled in Cryptarrhena lunata . Water-storage cells varied from thin-walled to variously banded throughout Maxillarieae. Cladistic analyses using anatomical characters yielded no resolution among subtribes, illustrating that anatomical characters are of limited value in assessing relationships within this tribe. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 251–274. [ABSTRACT FROM AUTHOR]

Despite formal separation based on molecular and morphological evidence, the genera Prosthechea Knowles & Westc. and Encyclia Hook. have not been studied in terms of their vegetative anatomy. In this study we examine 16 Brazilian species of these genera. Additionally, one species of subtribe Laeliinae and another from subtribe Oncidiinae were studied in order to evaluate the taxonomic consistency of the anatomic characters observed. Except for Epidendrum crassifolium Lindl., all species possess a velamen differentiated into epivelamen and endovelamen. Endodermal cells with uniformly thickened walls, calcium oxalate raphides and cells with phi thickenings in the cortical region were observed in all species. Silica bodies, raphides and fibre bundles in the mesophyll were common in leaves of all species studied. By contrast, flavonoid crystals were observed in both roots and leaves of Prosthechea only. Encyclia is characterized by the presence of fibre bundles on the subepidermal layer, and a cuticle, which is clearly thicker than that of Prosthechea. These data strongly support the separation of Prosthechea and Encyclia. © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 143, 293–303. [ABSTRACT FROM AUTHOR]