1.
Tagetes erecta
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Tagetes erecta, the Mexican marigold, also called Aztec marigold, is a species of the genus Tagetes native to Mexico. Despite its being native to the Americas, it is often called African marigold, in Mexico, this plant is found in the wild in the states of State of México, Puebla, and Veracruz. This plant reaches heights of between 50 and 100 cm, the Aztecs gathered the wild plant as well as cultivating it for medicinal, ceremonial and decorative purposes. It is widely cultivated commercially with many cultivars in use as ornamental plants and it is known as Daaspethiya in Sinhala language by Sri Lanka people. Its flower, the cempasúchil is also called the flor de muertos in Mexico and is used in the Día de los Muertos celebration every 2 November, the word cempazúchitl comes from the Nahuatl term for the flower cempohualxochitl, literally translated as twenty flower. In Thai language it is called ดาวเรือง, literally translated as star glittering, water infused with the fragrant essential oil of the flower was used to wash corpses in Honduras, and the flower is still commonly planted in cemeteries. Since prehispanic times, this plant has been used for medicinal purposes, the Cherokee used it as a skin wash and for yellow dye. This marigold may help protect certain crop plants from nematode pests when planted in fields and it is most effective against the nematode species Pratylenchus penetrans. The ray florets have been used in salads and other foods to add colour and flavour. This is still a use today, but now usually in the form of an extract which may have advantages of lower transport and storage cost, better stability and it is also used to enhance coloring in crustaceans, such as the Pacific white shrimp. The oil of the flower may be added to perfumes to infuse an apple scent into them, today, T. erecta is grown to extract lutein, a common yellow/orange food colour. The essential oil of the flower contains antioxidants, united States Department of Agriculture Plants Profile
2.
Taxonomy (biology)
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Taxonomy is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. The exact definition of taxonomy varies from source to source, but the core of the remains, the conception, naming. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy, the broadest meaning of taxonomy is used here. The word taxonomy was introduced in 1813 by Candolle, in his Théorie élémentaire de la botanique, the term alpha taxonomy is primarily used today to refer to the discipline of finding, describing, and naming taxa, particularly species. In earlier literature, the term had a different meaning, referring to morphological taxonomy, ideals can, it may be said, never be completely realized. They have, however, a value of acting as permanent stimulants. Some of us please ourselves by thinking we are now groping in a beta taxonomy, turrill thus explicitly excludes from alpha taxonomy various areas of study that he includes within taxonomy as a whole, such as ecology, physiology, genetics, and cytology. He further excludes phylogenetic reconstruction from alpha taxonomy, thus, Ernst Mayr in 1968 defined beta taxonomy as the classification of ranks higher than species. This activity is what the term denotes, it is also referred to as beta taxonomy. How species should be defined in a group of organisms gives rise to practical and theoretical problems that are referred to as the species problem. The scientific work of deciding how to define species has been called microtaxonomy, by extension, macrotaxonomy is the study of groups at higher taxonomic ranks, from subgenus and above only, than species. While some descriptions of taxonomic history attempt to date taxonomy to ancient civilizations, earlier works were primarily descriptive, and focused on plants that were useful in agriculture or medicine. There are a number of stages in scientific thinking. Early taxonomy was based on criteria, the so-called artificial systems. Later came systems based on a complete consideration of the characteristics of taxa, referred to as natural systems, such as those of de Jussieu, de Candolle and Bentham. The publication of Charles Darwins Origin of Species led to new ways of thinking about classification based on evolutionary relationships and this was the concept of phyletic systems, from 1883 onwards. This approach was typified by those of Eichler and Engler, the advent of molecular genetics and statistical methodology allowed the creation of the modern era of phylogenetic systems based on cladistics, rather than morphology alone. Taxonomy has been called the worlds oldest profession, and naming and classifying our surroundings has likely been taking place as long as mankind has been able to communicate
3.
Plant
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Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. The term is generally limited to the green plants, which form an unranked clade Viridiplantae. This includes the plants, conifers and other gymnosperms, ferns, clubmosses, hornworts, liverworts, mosses and the green algae. Green plants have cell walls containing cellulose and obtain most of their energy from sunlight via photosynthesis by primary chloroplasts and their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic and have lost the ability to produce amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although reproduction is also common. There are about 300–315 thousand species of plants, of which the great majority, green plants provide most of the worlds molecular oxygen and are the basis of most of Earths ecologies, especially on land. Plants that produce grains, fruits and vegetables form humankinds basic foodstuffs, Plants play many roles in culture. They are used as ornaments and, until recently and in variety, they have served as the source of most medicines. The scientific study of plants is known as botany, a branch of biology, Plants are one of the two groups into which all living things were traditionally divided, the other is animals. The division goes back at least as far as Aristotle, who distinguished between plants, which generally do not move, and animals, which often are mobile to catch their food. Much later, when Linnaeus created the basis of the system of scientific classification. Since then, it has become clear that the plant kingdom as originally defined included several unrelated groups, however, these organisms are still often considered plants, particularly in popular contexts. When the name Plantae or plant is applied to a group of organisms or taxon. The evolutionary history of plants is not yet settled. Those which have been called plants are in bold, the way in which the groups of green algae are combined and named varies considerably between authors. Algae comprise several different groups of organisms which produce energy through photosynthesis, most conspicuous among the algae are the seaweeds, multicellular algae that may roughly resemble land plants, but are classified among the brown, red and green algae. Each of these groups also includes various microscopic and single-celled organisms
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Flowering plant
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The flowering plants, also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants, with 416 families, approx. 13,164 known genera and a total of c.295,383 known species, etymologically, angiosperm means a plant that produces seeds within an enclosure, in other words, a fruiting plant. The term angiosperm comes from the Greek composite word meaning enclosed seeds, the ancestors of flowering plants diverged from gymnosperms in the Triassic Period, during the range 245 to 202 million years ago, and the first flowering plants are known from 160 mya. They diversified extensively during the Lower Cretaceous, became widespread by 120 mya, angiosperms differ from other seed plants in several ways, described in the table. These distinguishing characteristics taken together have made the angiosperms the most diverse and numerous land plants, the amount and complexity of tissue-formation in flowering plants exceeds that of gymnosperms. The vascular bundles of the stem are arranged such that the xylem and phloem form concentric rings, in the dicotyledons, the bundles in the very young stem are arranged in an open ring, separating a central pith from an outer cortex. In each bundle, separating the xylem and phloem, is a layer of meristem or active formative tissue known as cambium, the soft phloem becomes crushed, but the hard wood persists and forms the bulk of the stem and branches of the woody perennial. Among the monocotyledons, the bundles are more numerous in the stem and are scattered through the ground tissue. They contain no cambium and once formed the stem increases in diameter only in exceptional cases, the characteristic feature of angiosperms is the flower. Flowers show remarkable variation in form and elaboration, and provide the most trustworthy external characteristics for establishing relationships among angiosperm species, the function of the flower is to ensure fertilization of the ovule and development of fruit containing seeds. The floral apparatus may arise terminally on a shoot or from the axil of a leaf, occasionally, as in violets, a flower arises singly in the axil of an ordinary foliage-leaf. There are two kinds of cells produced by flowers. Microspores, which divide to become pollen grains, are the male cells and are borne in the stamens. The female cells called megaspores, which divide to become the egg cell, are contained in the ovule. The flower may consist only of parts, as in willow. Usually, other structures are present and serve to protect the sporophylls, the individual members of these surrounding structures are known as sepals and petals. The outer series is usually green and leaf-like, and functions to protect the rest of the flower, the inner series is, in general, white or brightly colored, and is more delicate in structure. It functions to attract insect or bird pollinators, attraction is effected by color, scent, and nectar, which may be secreted in some part of the flower
5.
Eudicots
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The eudicots, Eudicotidae or eudicotyledons are a monophyletic clade of flowering plants that had been called tricolpates or non-magnoliid dicots by previous authors. The close relationships among flowering plants with tricolpate pollen grains was initially seen in studies of shared derived characters. These plants have a trait in their pollen grains of exhibiting three colpi or grooves paralleling the polar axis. Later molecular evidence confirmed the basis for the evolutionary relationships among flowering plants with tricolpate pollen grains. The term means true dicotyledons, as it contains the majority of plants that have been considered dicots and have characteristics of the dicots, the term eudicots has subsequently been widely adopted in botany to refer to one of the two largest clades of angiosperms, monocots being the other. The remaining angiosperms are sometimes referred to as basal angiosperms or paleodicots, the other name for the eudicots is tricolpates, a name which refers to the grooved structure of the pollen. Members of the group have tricolpate pollen, or forms derived from it and these pollens have three or more pores set in furrows called colpi. In contrast, most of the seed plants produce monosulcate pollen. The name tricolpates is preferred by some botanists to avoid confusion with the dicots, numerous familiar plants are eudicots, including many common food plants, trees, and ornamentals. Most leafy trees of midlatitudes also belong to eudicots, with exceptions being magnolias and tulip trees which belong to magnoliids, and Ginkgo biloba. The name eudicots is used in the APG system, of 1998 and it is applied to a clade, a monophyletic group, which includes most of the dicots. The eudicots can be divided into two groups, the basal eudicots and the core eudicots, basal eudicot is an informal name for a paraphyletic group. The core eudicots are a monophyletic group, a 2010 study suggested the core eudicots can be divided into two clades, Gunnerales and a clade called Pentapetalae, comprising all the remaining core eudicots
6.
Asterids
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In the APG IV system for the classification of flowering plants, the name asterids denotes a clade. Most of the taxa belonging to this clade had been referred to the Asteridae in the Cronquist system, the name asterids resembles the earlier botanical name but is intended to be the name of a clade rather than a formal ranked name, in the sense of the ICBN. The phylogenetic tree presented hereafter has been proposed by the APG IV project, genetic analysis carried out after APG II maintains that the sister to all other asterids are the Cornales. A second order that split from the base of the asterids are the Ericales, the remaining orders cluster into two clades, the lamiids and the campanulids. The structure of both of these clades has changed in APG III, in APG III system, the following clades were renamed, euasterids I → lamiids euasterids II → campanulids Asterids in Stevens, P. F. Angiosperm Phylogeny Website
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Asterales
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The order is a cosmopolite, and includes mostly herbaceous species, although a small number of trees and shrubs are also present. Asterales are organisms that seem to have evolved from one common ancestor, Asterales share characteristics on morphological and biochemical levels. Synapomorphies include the presence in the plants of oligosaccharide inulin, a nutrient storage molecule used instead of starch, under the Cronquist system of taxonomic classification of flowering plants, Asteraceae was the only family in the group, but newer systems have expanded it to 11. In the classification system of Dahlgren the Asterales were in the superorder Asteriflorae, the order Asterales currently includes 11 families, the largest of which are the Asteraceae, with about 25,000 species, and the Campanulaceae, with about 2,000 species. The remaining families count together for less than 500 species, the phylogenetic tree according to APG III for the Campanulid clade is as below. The core Asterales are Stylidiaceae, APA clade, MGCA clade, other Asterales are Rousseaceae, Campanulaceae and Pentaphragmataceae. All Asterales families are represented in the Southern Hemisphere, however, Asteraceae and Campanulaceae are cosmopolitan, less can be said about the Asterales themselves with certainty, although since several families in Asterales contain trees, the ancestral member is most likely to have been a tree or shrub. Because all clades are represented in the southern hemisphere but many not in the northern hemisphere, Asterales are angiosperms, flowering plants that appeared about 140 million years ago. Asterales contain about 14% of eudicot diversity, however few fossils have been found, of the Menyanthaceae-Asteraceae clade in the Oligocene, about 29 Mya. Fossil evidence of the Asterales is rare and belongs to rather recent epochs, an Oligocene pollen is known for Asteraceae and Goodeniaceae, and seeds from Oligocene and Miocene are known for Menyanthaceae and Campanulaceae respectively. The Asterales, by dint of being a super-set of the family Asteraceae, include some species grown for food, including the sunflower, lettuce, many are also used as spices and traditional medicines. Asterales are common plants and have many known uses, for example, pyrethrum is a natural insecticide with minimal environmental impact. Wormwood, derived from a genus that includes the sagebrush, is used as a source of flavoring for absinthe, despite the large number of species in order Asterales, they do not compare in economic benefit for mankind to the Poales or to the Fabaceae. The Asteraceae include many plant species in North America. W. S. Judd, C. S. Campbell, E. A. Kellogg, P. F. Stevens, plant Systematics, A Phylogenetic Approach, 2nd edition. In, Nature Encyclopedia of Life Sciences, Asterales - Definition and More from the Free Merriam-Webster Dictionary. Dictionary and Thesaurus - Merriam-Webster Online
8.
Asteraceae
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Asteraceae or Compositae is a very large and widespread family of flowering plants. The family currently has 32,913 accepted species names, in 1,911 genera and 13 subfamilies, in terms of numbers of species, the Asteraceae are rivaled only by the Orchidaceae. Many members have composite flowers in the form of flower heads surrounded by involucral bracts, when viewed from a distance, each capitulum may have the appearance of being a single flower. The name Asteraceae comes from the type genus Aster, from the Greek ἀστήρ, meaning star, Compositae is an older but still valid name which refers to the fact that the family is one of the few angiosperm ones to have composite flowers. Most members of Asteraceae are herbaceous, but a significant number are also shrubs, vines, the family has a worldwide distribution, from the polar regions to the tropics, colonizing a wide variety of habitats. It is most common in the arid and semiarid regions of subtropical, the Asteraceae may represent as much as 10% of autochthonous flora in many regions of the world. Asteraceae is an important family, providing products such as cooking oils, lettuce, sunflower seeds, artichokes, sweetening agents, coffee substitutes. Several genera are of importance, including pot marigold, Calendula officinalis, Echinacea, various daisies, fleabane, chrysanthemums, dahlias, zinnias. Asteraceae are important in medicine, including Grindelia, yarrow. A number of species are considered invasive, including, most notably in North America, dandelion, the name Asteraceae comes to international scientific vocabulary from New Latin, from Aster, the type genus, + -aceae, a standardized suffix for plant family names in modern taxonomy. The genus name comes from the Classical Latin word aster, star, Compositae, an older but still valid name, means composite and refers to the characteristic inflorescence, a special type of pseudanthium found in only a few other angiosperm families. The study of family is known as synantherology. The vernacular name daisy, widely applied to members of family, is derived from its Old English name, dægesege, from dæges eage. This is because the open at dawn and close at dusk. Composite flowers have a distribution, and are found everywhere except Antarctica. They are especially numerous in tropical and subtropical regions, Compositae were first described in 1792 by the German botanist Paul Dietrich Giseke. Traditionally, two subfamilies were recognised, Asteroideae and Cichorioideae, the latter has been shown to be extensively paraphyletic, and has now been divided into 12 subfamilies, but the former still stands. The phylogenetic tree presented below is based on Panero & Funk updated in 2014, the diamond denotes a very poorly supported node, the dot a poorly supported node
