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Regine Claßen-bockhoff - One of the best experts on this subject based on the ideXlab platform.
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Modeling dense Inflorescences
ACM Transactions on Graphics, 2016Co-Authors: Andrew Owens, Regine Claßen-bockhoff, Mikolaj Cieslak, Jeremy Hart, Przemyslaw PrusinkiewiczAbstract:Showy Inflorescences - clusters of flowers - are a common feature of many plants, greatly contributing to their beauty. The large numbers of individual flowers (florets), arranged in space in a systematic manner, make Inflorescences a natural target for procedural modeling. We present a suite of biologically motivated algorithms for modeling and animating the development of Inflorescences with closely packed florets. These Inflorescences share the following characteristics: (i) in their ensemble, the florets form a relatively smooth, often approximately planar surface; (ii) there are numerous collisions between petals of the same or adjacent florets; and (iii) the developmental stage and type of a floret may depend on its position within the Inflorescence, with drastic or gradual differences. To model flat-topped branched Inflorescences (corymbs and umbels), we propose a florets-first algorithm, in which the branching structure self-organizes to support florets in predetermined positions. This is an alternative to previous branching-first models, in which floret positions were determined by branch arrangement. To obtain realistic visualizations, we complement the algorithms that generate the Inflorescence structure with an interactive method for modeling floret corollas (petal sets). The method supports corollas with both separate and fused petals. We illustrate our techniques with models from several plant families.
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Towards an ontogenetic understanding of Inflorescence diversity
Annals of botany, 2013Co-Authors: Regine Claßen-bockhoff, Kester Bull-hereñuAbstract:Backgrounds and aims Conceptual and terminological conflicts in Inflorescence morphology indicate a lack of understanding of the phenotypic diversity of Inflorescences. In this study, an ontogeny-based Inflorescence concept is presented considering different meristem types and developmental pathways. By going back to the ontogenetic origin, diversity is reduced to a limited number of types and terms. Methods Species from 105 genera in 52 angiosperm families are investigated to identify their specific reproductive meristems and developmental pathways. Based on these studies, long-term experience with Inflorescences and literature research, a conceptual framework for the understanding of Inflorescences is presented. Key results Ontogeny reveals that reproductive systems traditionally called Inflorescences fall into three groups, i.e. 'flowering shoot systems' (FSS), 'Inflorescences' sensu stricto and 'floral units' (FUs). Our concept is, first, based on the identification of reproductive meristem position and developmental potential. The FSS, defined as a seasonal growth unit, is used as a reference framework. As the FSS is a leafy shoot system bearing reproductive units, foliage and flowering sequence play an important role. Second, the identification of two different flower-producing meristems is essential. While 'Inflorescence meristems' (IMs) share acropetal primordia production with vegetative meristems, 'floral unit meristems' (FUMs) resemble flower meristems in being indeterminate. IMs produce the basic Inflorescence types, i.e. compound and simple racemes, panicles and botryoids. FUMs give rise to dense, often flower-like units (e.g. heads). They occur solitarily at the FSS or occupy flower positions in Inflorescences, rendering the latter thyrses in the case of cymose branching. Conclusions The ontogenetic concept differs from all existing Inflorescence concepts in being based on meristems and developmental processes. It includes clear terms and allows homology statements. Transitional forms are an explicit part of the concept, illustrating the ontogenetic potential for character transformation in evolution.
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Testing the ontogenetic base for the transient model of Inflorescence development.
Annals of botany, 2013Co-Authors: Kester Bull-hereñu, Regine Claßen-bockhoffAbstract:Backgrounds and aims Current research in plant science has concentrated on revealing ontogenetic processes of key attributes in plant evolution. One recently discussed model is the 'transient model' successful in explaining some types of Inflorescence architectures based on two main principles: the decline of the so called 'vegetativeness' (veg) factor and the transient nature of apical meristems in developing Inflorescences. This study examines whether both principles find a concrete ontogenetic correlate in Inflorescence development. Methods To test the ontogenetic base of veg decline and the transient character of apical meristems the ontogeny of meristematic size in developing Inflorescences was investigated under scanning electron microscopy. Early and late Inflorescence meristems were measured and compared during Inflorescence development in 13 eudicot species from 11 families. Key results The initial size of the Inflorescence meristem in closed Inflorescences correlates with the number of nodes in the mature Inflorescence. Conjunct compound Inflorescences (panicles) show a constant decrease of meristematic size from early to late Inflorescence meristems, while disjunct compound Inflorescences present an enlargement by merging from early Inflorescence meristems to late Inflorescence meristems, implying a qualitative change of the apical meristems during ontogeny. Conclusions Partial confirmation was found for the transient model for Inflorescence architecture in the ontogeny: the initial size of the apical meristem in closed Inflorescences is consistent with the postulated veg decline mechanism regulating the size of the Inflorescence. However, the observed biphasic kinetics of the development of the apical meristem in compound racemes offers the primary explanation for their disjunct morphology, contrary to the putative exclusive transient mechanism in lateral axes as expected by the model.
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PREFACE: PART OF A SPECIAL ISSUE ON InflorescenceS Inflorescences: concepts, function, development and evolution
2013Co-Authors: Bruce K. Kirchoff, Regine Claßen-bockhoffAbstract:† Background Inflorescences are complex structures with many functions. At anthesis they present the flowers in ways that allow for the transfer of pollen and optimization of the plant’s reproductive success. During flower and fruit development they provide nutrients to the developing flowers and fruits. At fruit maturity they support the fruitspriortodispersal,andfacilitateeffectivefruitandseeddispersal.Fromastructuralpointofview,Inflorescences have played important roles in systematic and phylogenetic studies. As functional unitsthey facilitate reproduction, and are largely shaped by natural selection. † ScopeThepapersinthisSpecialIssuebridgethegapbetweenstructuralandfunctionalapproachestoInflorescence evolution. They include a literature review of Inflorescence function, an experimental study of Inflorescences as essentialcontributorstothedisplayofflowers,andtwopapersthatpresentnewmethodsandconceptsforunderstanding Inflorescencediversityandfordealingwithterminologicalproblems.ThetransientmodelofInflorescencedevelopmentis evaluatedin anontogenetic study, and partiallysupported. Four papers presentmorphological and ontogenetic studies of Inflorescence development in monophyletic groups, and two of these evaluate the usefulness of Hofmeister’s Rule and inhibitory fields to predict Inflorescence structure. In the final two papers, Bayesian and Monte-CarlomethodsareusedtoelucidateInflorescenceevolutioninthePanicoidgrasses,andacandidategeneapproach is used in an attempt to understand the evolutionary genetics of Inflorescence evolution in the genus Cornus (Cornaceae).Takenasawhole,thepapersinthisissueprovideaglimpseofcontemporaryapproachestothestudyof the structure, development, and evolution of Inflorescences, and suggest fruitful new directions for research.
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Inflorescences: concepts, function, development and evolution.
Annals of botany, 2013Co-Authors: Bruce K. Kirchoff, Regine Claßen-bockhoffAbstract:Background Inflorescences are complex structures with many functions. At anthesis they present the flowers in ways that allow for the transfer of pollen and optimization of the plant's reproductive success. During flower and fruit development they provide nutrients to the developing flowers and fruits. At fruit maturity they support the fruits prior to dispersal, and facilitate effective fruit and seed dispersal. From a structural point of view, Inflorescences have played important roles in systematic and phylogenetic studies. As functional units they facilitate reproduction, and are largely shaped by natural selection. Scope The papers in this Special Issue bridge the gap between structural and functional approaches to Inflorescence evolution. They include a literature review of Inflorescence function, an experimental study of Inflorescences as essential contributors to the display of flowers, and two papers that present new methods and concepts for understanding Inflorescence diversity and for dealing with terminological problems. The transient model of Inflorescence development is evaluated in an ontogenetic study, and partially supported. Four papers present morphological and ontogenetic studies of Inflorescence development in monophyletic groups, and two of these evaluate the usefulness of Hofmeister's Rule and inhibitory fields to predict Inflorescence structure. In the final two papers, Bayesian and Monte-Carlo methods are used to elucidate Inflorescence evolution in the Panicoid grasses, and a candidate gene approach is used in an attempt to understand the evolutionary genetics of Inflorescence evolution in the genus Cornus (Cornaceae). Taken as a whole, the papers in this issue provide a glimpse of contemporary approaches to the study of the structure, development, and evolution of Inflorescences, and suggest fruitful new directions for research.
Christophe Clement - One of the best experts on this subject based on the ideXlab platform.
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endophytic colonization of vitis vinifera l by burkholderia phytofirmans strain psjn from the rhizosphere to Inflorescence tissues
FEMS Microbiology Ecology, 2008Co-Authors: Stephane Compant, Herve Kaplan, Angela Sessitsch, Jerzy Nowak, Essaid Ait Barka, Christophe ClementAbstract:The colonization pattern of Vitis vinifera L. by Burkholderia phytofirmans strain PsJN was determined using grapevine fruiting cuttings with emphasis on putative Inflorescence colonization under nonsterile conditions. Two-week-old rooted plants harbouring flower bud initials, grown in nonsterile soil, were inoculated with PsJN:gfp2x. Plant colonization was subsequently monitored at various times after inoculation with plate counts and epifluorescence and/or confocal microscopy. Strain PsJN was chronologically detected on the root surfaces, in the endorhiza, inside grape Inflorescence stalks, not inside preflower buds and flowers but rather as an endophyte inside young berries. Data demonstrated low endophytic populations of strain PsJN in Inflorescence organs, i.e. grape stalks and immature berries with inconsistency among plants for bacterial colonization of Inflorescences. Nevertheless, endophytic colonization of Inflorescences by strain PsJN was substantial for some plants. Microscopic analysis revealed PsJN as a thriving endophyte in Inflorescence organs after the colonization process. Strain PsJN was visualized colonizing the root surface, entering the endorhiza and spreading to grape Inflorescence stalks, pedicels and then to immature berries through xylem vessels. In parallel to these observations, a natural microbial communities was also detected on and inside plants, demonstrating the colonization of grapevine by strain PsJN in the presence of other microorganisms.
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Photosynthesis of the grapevine (Vitis vinifera) Inflorescence.
Tree physiology, 2005Co-Authors: Gaël Lebon, Olivier Brun, Christian Magné, Christophe ClementAbstract:To further characterize carbohydrate physiology in grapevine flowers, we examined Inflorescence autotrophy in the ‘Gewurztraminer’ and ‘Pinot noir’ cultivars, which differ in sensitivity to flower abscission. In both cultivars, positive net photosynthesis occurred in Inflorescences. The rate of photosynthesis gradually decreased throughout flower development and there was no net carbon assimilation at fruit set. The rate of photosynthesis was positively correlated with chlorophyll concentration but not to stomatal conductance. Throughout flower development, the internal CO 2 concentration increased in Inflorescence tissues, suggesting that assimilates are also formed through refixation of respiratory CO 2 by the phosphoenolpyruvate carboxylase (PEPC) pathway. Significant differences between the two cultivars were recorded during meiosis, when photosynthesis was higher in ‘Gewurztraminer’. We conclude that the Inflorescence of grapevine contributes to its own carbon nutrition by photosynthesizing throughout flower development. Moreover, the differential patterns of photosynthesis in the Inflorescences of ‘Gewurztraminer’ and ‘Pinot noir’ might account for their differing fertilization rates and sensitivity to flower abscission.
Stefan Dötterl - One of the best experts on this subject based on the ideXlab platform.
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Nocturnal Plant Bugs Use cis-Jasmone to Locate Inflorescences of an Araceae as Feeding and Mating Site
Journal of Chemical Ecology, 2016Co-Authors: Florian Etl, Andreas Berger, Anton Weber, Jürg Schönenberger, Stefan DötterlAbstract:Inflorescences of Araceae pollinated by cyclocephaline scarab beetles are visited frequently by a wide array of other arthropods that exploit floral resources without taking part in pollination, including earwigs, flies, and true bugs. To date, nothing is known about the cues these insect visitors use to locate the Inflorescences and whether or to what extent floral scents play a role. An aroid visited by large numbers of plant bugs (Miridae) in addition to cyclocephaline scarab beetle pollinators is the Neotropical species Dieffenbachia aurantiaca . We identified the plant bug species and investigated their behavior and arrival time on the Inflorescences. To test the importance of olfactory cues in locating their host we conducted experiments with open and gauze-bagged Inflorescences as well as natural scent samples of D. aurantiaca . Inflorescence scents were analyzed by gas chromatography linked to mass spectrometry (GC/MS), and the attractive potential of the main scent compound was determined by behavioral assays. Three species of Neella , the most common one being N. floridula , visited the Inflorescences at nightfall, shortly after the beginning of scent emission, and showed feeding and copulation activity. Bagged Inflorescences as well as natural scent samples attracted similar numbers of plant bugs as the non-bagged Inflorescences, showing that olfactory cues are sufficient for them to locate their host. Cis -jasmone was the major component within the Inflorescence scent bouquet. In two-choice field bioassays, this compound proved to be highly attractive to Neella , and thus obviously plays a key role in finding host plants.
Kester Bull-hereñu - One of the best experts on this subject based on the ideXlab platform.
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Towards an ontogenetic understanding of Inflorescence diversity
Annals of botany, 2013Co-Authors: Regine Claßen-bockhoff, Kester Bull-hereñuAbstract:Backgrounds and aims Conceptual and terminological conflicts in Inflorescence morphology indicate a lack of understanding of the phenotypic diversity of Inflorescences. In this study, an ontogeny-based Inflorescence concept is presented considering different meristem types and developmental pathways. By going back to the ontogenetic origin, diversity is reduced to a limited number of types and terms. Methods Species from 105 genera in 52 angiosperm families are investigated to identify their specific reproductive meristems and developmental pathways. Based on these studies, long-term experience with Inflorescences and literature research, a conceptual framework for the understanding of Inflorescences is presented. Key results Ontogeny reveals that reproductive systems traditionally called Inflorescences fall into three groups, i.e. 'flowering shoot systems' (FSS), 'Inflorescences' sensu stricto and 'floral units' (FUs). Our concept is, first, based on the identification of reproductive meristem position and developmental potential. The FSS, defined as a seasonal growth unit, is used as a reference framework. As the FSS is a leafy shoot system bearing reproductive units, foliage and flowering sequence play an important role. Second, the identification of two different flower-producing meristems is essential. While 'Inflorescence meristems' (IMs) share acropetal primordia production with vegetative meristems, 'floral unit meristems' (FUMs) resemble flower meristems in being indeterminate. IMs produce the basic Inflorescence types, i.e. compound and simple racemes, panicles and botryoids. FUMs give rise to dense, often flower-like units (e.g. heads). They occur solitarily at the FSS or occupy flower positions in Inflorescences, rendering the latter thyrses in the case of cymose branching. Conclusions The ontogenetic concept differs from all existing Inflorescence concepts in being based on meristems and developmental processes. It includes clear terms and allows homology statements. Transitional forms are an explicit part of the concept, illustrating the ontogenetic potential for character transformation in evolution.
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Testing the ontogenetic base for the transient model of Inflorescence development.
Annals of botany, 2013Co-Authors: Kester Bull-hereñu, Regine Claßen-bockhoffAbstract:Backgrounds and aims Current research in plant science has concentrated on revealing ontogenetic processes of key attributes in plant evolution. One recently discussed model is the 'transient model' successful in explaining some types of Inflorescence architectures based on two main principles: the decline of the so called 'vegetativeness' (veg) factor and the transient nature of apical meristems in developing Inflorescences. This study examines whether both principles find a concrete ontogenetic correlate in Inflorescence development. Methods To test the ontogenetic base of veg decline and the transient character of apical meristems the ontogeny of meristematic size in developing Inflorescences was investigated under scanning electron microscopy. Early and late Inflorescence meristems were measured and compared during Inflorescence development in 13 eudicot species from 11 families. Key results The initial size of the Inflorescence meristem in closed Inflorescences correlates with the number of nodes in the mature Inflorescence. Conjunct compound Inflorescences (panicles) show a constant decrease of meristematic size from early to late Inflorescence meristems, while disjunct compound Inflorescences present an enlargement by merging from early Inflorescence meristems to late Inflorescence meristems, implying a qualitative change of the apical meristems during ontogeny. Conclusions Partial confirmation was found for the transient model for Inflorescence architecture in the ontogeny: the initial size of the apical meristem in closed Inflorescences is consistent with the postulated veg decline mechanism regulating the size of the Inflorescence. However, the observed biphasic kinetics of the development of the apical meristem in compound racemes offers the primary explanation for their disjunct morphology, contrary to the putative exclusive transient mechanism in lateral axes as expected by the model.
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Ontogenetic Course and Spatial Constraints in the Appearance and Disappearance of the Terminal Flower in Inflorescences
International Journal of Plant Sciences, 2011Co-Authors: Kester Bull-hereñu, Regine Claßen-bockhoffAbstract:Inflorescences are usually designed as closed or open, referring to the presence or absence of a terminal flower (TF), respectively. Until now, it was unknown how much developmental constraints in the Inflorescence meristem (IM) determined the production of the TF. To face this question, we carried out a quantitative study of Inflorescence development including 19 species from four families of the eudicots (Berberidaceae, Papaveraceae-Fumarioideae, Rosaceae, and Campanulaceae). Our study shows that TFs appear on IMs that possess a certain relative surface, phyllotaxis, and convexity. IMs of open Inflorescences show a significantly smaller relative surface (
Abelardo C. Vegetti - One of the best experts on this subject based on the ideXlab platform.
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Uncovering the Inflorescence evolution of Eleusininae (Cynodonteae: Chloridoideae: Poaceae)
Botanical Journal of the Linnean Society, 2019Co-Authors: SebastiÁn E. Muchut, Abelardo C. Vegetti, Vanesa Pilatti, Andrea G. Reutemann, Nora G Uberti Manassero, Renata ReinheimerAbstract:Abstract Inflorescence forms in grasses lead to a general assumption that their evolution is random. We reconstructed the ancestral Inflorescence for Poaceae subtribe Eleusininae and outlined possible evolutionary pathways to test the hypotheses of (1) non-directionality in grass Inflorescence evolution and (2) an evolutionary direction from complex to simpler Inflorescence architectures in this lineage. By studying early stages of Inflorescence and spikelet development, we investigated ontogenetic changes that may correlate with evolutionary pathways identified. The approach presented here indicates that the current diversity of Inflorescences found in Eleusininae is probably a result of two distinct evolutionary pathways. The main path involves a multi-staged course with shortening of main axis internodes first, followed by a decrease in number of primary branches and florets per spikelet. We postulate that reduced elongation of the internodes may affect the apical and axillary meristems performance, which in turn promotes a decrease in the number of primary branches and floret per spikelet. Current diversity in Inflorescences of Eleusininae may be a consequence of a reductive evolution. We found that the evolutionary directionality of Inflorescences in Eleusininae may be associated with developmental events that affected Inflorescence morphology at early stages.
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Diversity, systematics, and evolution of Cynodonteae Inflorescences (Chloridoideae – Poaceae)
2017Co-Authors: Vanesa Pilatti, Abelardo C. Vegetti, SebastiÁn E. Muchut, Nora G. Uberti-manassero, Renata ReinheimerAbstract:The species of the Cynodonteae tribe show great morphological diversity in their reproductive structures. Previous studies where Inflorescences were comparatively analysed in the context of phylogeny have shown that although grass Inflorescences seem to be excessively variable, there are certain aspects of Inflorescences that store relevant information on the evolution and systematics in Poaceae. We have analysed and compared the Inflorescence structures of species belonging to the Hilariinae, Monanthochloinae, Scleropogoninae, and Muhlenbergiinae subtribes. Considering the most relevant morphological characters, the most recurrent types of Inflorescences in the lineage were determined by means of a principal coordinates analysis. To understand the evolution of Inflorescence morphology, ancestral reconstructions of Inflorescence characters were performed using the Bayesian inference method. The results obtained demonstrate that the processes of homogenization and truncation might account for the diversity observed in adult Inflorescences. Five different types of Inflorescences were identified out of 36 theoretical possibilities. Amongst these, Inflorescence type 1 (panicle of spikelets, with a terminal spikelet, non-homogenized, and bearing third- or higher-order branches) was found to be the most frequent in the studied group. Ancestral reconstructions of morphological characters allowed us to suggest that the ancestor of the group might have had an Inflorescence with the form of a raceme of spikelets, non-truncated and bearing first-order branches. More complex Inflorescences bearing no terminal spikelets and having branches of higher order might have diverged this lineage.
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Inflorescence diversity in subtribe Eleusininae (Poaceae: Chloridoideae: Cynodonteae)
Flora, 2017Co-Authors: SebastiÁn E. Muchut, Abelardo C. Vegetti, Vanesa Pilatti, Nora G. Uberti-manassero, Renata ReinheimerAbstract:Abstract We studied the Inflorescences of 112 members of tribe Chloridoideae subtribe Eleusininae from a morphological and evolutionary perspective to identify the most frequent types and to explore the evolutionary history of selected Inflorescence associated characters. Six characters were scored on adult specimens and a principal coordinate analysis was conducted to identify Inflorescence types. To investigate the evolution of Inflorescences we regenerated the phylogeny of the subtribe and performed ancestral character state reconstructions using Maximum Parsimony. All species have panicles of spikelets with pyramidal, digitate or single-branched appearances. The number of primary branches varies widely among species, although some species have a single primary branch. The lack of terminal spikelet (truncation) and the similarity among primary branches of the Inflorescence (homogenization) characterize the majority of the subtribe. In Eleusininae, the spikelet may be uni-, two- or multi-flowered. We found 13 Inflorescence types in the group among 72 putative Inflorescence forms. About 75% of the species can be divided to five different Inflorescence types. Ancestral state reconstruction suggests an evolutionary direction towards simpler Inflorescences with spikelets that contain 1–2 florets.
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Inflorescence development in Abildgaardieae (Cyperaceae, Cyperoideae)
Flora - Morphology Distribution Functional Ecology of Plants, 2015Co-Authors: Andrea G. Reutemann, Abelardo C. Vegetti, Raúl PoznerAbstract:Abstract Inflorescences in Cyperaceae are a source of characters with significant systematic value; however, the structure and primary homologies pose a challenge to their interpretation. The relationships among members of Abildgaardieae are not clear due to the absence of a phylogeny with strong support, comprising a representative number of species. Establishing correct primary homologies of Inflorescences within Abildgaardieae might help to clarify the relationships among its members, as well as to find synapomorphies for the most important clades. Variations in the mature Inflorescences within Abildgaardieae have been related to their “shape” and “structure”, and preliminary phylogenetic studies in species of Bulbostylis have shown that Inflorescence structure traits are phylogenetically informative, but this is not true for the mere shape. While similar structures in the adult Inflorescences of the members of different clades within Abildgaardieae might be considered homologous, it must be ascertained whether such similar structures share the same developmental process or have different developmental patterns. By studying the development of Inflorescences in selected species of Abildgaardieae using SEM, we were able to show that Inflorescences with homologous structures share a similar developmental process and, therefore, the adult structure of Inflorescences may be relied on for establishing correct primary morphological homologies in this plant group. Most structural variations of Inflorescences in Abildgaardieae depend on the degree of development of processes shared by the studied species. While phyllotaxis in the main axis of Cyperus may be modified during Inflorescence development after primordial inception, variations in the phyllotactic patterns of leaves on vegetative shoots (=nomophylls) and of leaves on fertile shoots (=bracts or hypsophylls) within Abildgaardieae, might establish deeper differences in Inflorescence structure, since they depend on changes in the shape of the apical meristem.
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Structure of the Cyperaceae Inflorescence
The Botanical Review, 2012Co-Authors: Andrea G. Reutemann, Leandro Lucero, Nicolas Javier Guarise, Abelardo C. VegettiAbstract:This work presents the basics for interpreting the adult Inflorescence structure in Cyperaceae. It provides an analysis of the variations of the synflorescence and Inflorescence structure in the family. Three types of synflorescence may be recognized in this family: a synflorescence with a foliate stem, a terminal Inflorescence and a variable number of lateral Inflorescences; a synflorescence with a foliate stem and only the terminal Inflorescence; and a synflorescence with a scape and a terminal Inflorescence. Variations in the structure and form of the Inflorescences are related to variations in Inflorescence branching, Inflorescence homogenization degree, presence or absence of the distal part of the Inflorescence, phyllotaxis, Inflorescence position, types of bracts and leaves subtending branches, elongation of Inflorescence internodes and spikelet structure. These variations are correlated with some of the developmental processes that give origin to the Inflorescence.
