Michelia is a historical genus of flowering plants belonging to the family Magnoliaceae . The genus included about 50 species of evergreen trees and shrubs , native to tropical and subtropical south and southeast Asia ( Indomalaya ), including southern China . Today it is regarded as a synonym and section of the genus Magnolia .
121-558: The Magnoliaceae are an ancient family; fossil plants identifiably belonging to the Magnoliaceae date back 95 million years. A primitive aspect of the Magnolia family is that their large, cup-shaped flowers lack distinct petals or sepals . The large non-specialized flower parts, resembling petals, are called tepals . The leaves, flowers, and form of Michelia resemble Magnolia , but the blossoms of Michelia generally form clusters among
242-520: A diploid (two copies of each chromosome ) cell. Whereas in fertilization only plasmogamy, or the fusion of the whole sex cells, results, in Angiosperms (flowering plants) a process known as double fertilization, which involves both karyogamy and plasmogamy, occurs. In double fertilization the second sperm cell subsequently also enters the synergid and fuses with the two polar nuclei of the central cell. Since all three nuclei are haploid , they result in
363-411: A filament , or stalk. The anther contains microsporocytes which become pollen , the male gametophyte , after undergoing meiosis . Although they exhibit the widest variation among floral organs, the androecium is usually confined just to one whorl and to two whorls only in rare cases. Stamens range in number, size, shape, orientation, and in their point of connection to the flower. In general, there
484-776: A 60,000-year-old Neanderthal burial site, " Shanidar IV ", in northern Iraq has yielded large amounts of pollen from eight plant species, seven of which are used now as herbal remedies. Also, a mushroom was found in the personal effects of Ötzi the Iceman , whose body was frozen in the Ötztal Alps for more than 5,000 years. The mushroom was probably used against whipworm . In ancient Sumeria , hundreds of medicinal plants including myrrh and opium are listed on clay tablets from around 3000 BC. The ancient Egyptian Ebers Papyrus lists over 800 plant medicines such as aloe , cannabis , castor bean , garlic , juniper , and mandrake . In antiquity, various cultures across Europe, including
605-411: A broad base, stomata and chlorophyll and may have stipules . Sepals are often waxy and tough, and grow quickly to protect the flower as it develops. They may be deciduous , but will more commonly grow on to assist in fruit dispersal. If the calyx is fused it is called gamosepalous. The petals , or corolla, are almost or completely fiberless leaf-like structures that form the innermost whorl of
726-404: A different flower of the same plant, but others have mechanisms to prevent self-pollination and rely on cross-pollination , when pollen is transferred from the anther of one flower to the stigma of another flower on a different individual of the same species. Self-pollination happens in flowers where the stamen and carpel mature at the same time, and are positioned so that the pollen can land on
847-418: A different plant of the same species. Because the genetic make-up of the sperm contained within the pollen from the other plant is different, their combination will result in a new, genetically distinct, plant, through the process of sexual reproduction . Since each new plant is genetically distinct, the different plants show variation in their physiological and structural adaptations and so the population as
968-425: A food source for pollinators. In this way, many flowering plants have co-evolved with pollinators to be mutually dependent on services they provide to one another—in the plant's case, a means of reproduction; in the pollinator's case, a source of food. When pollen from the anther of a flower is deposited on the stigma , this is called pollination. Some flowers may self-pollinate , producing seed using pollen from
1089-482: A healthier labour force. However, development of plants or extracts having potential medicinal uses is blunted by weak scientific evidence, poor practices in the process of drug development , and insufficient financing. All plants produce chemical compounds which give them an evolutionary advantage, such as defending against herbivores or, in the example of salicylic acid , as a hormone in plant defenses. These phytochemicals have potential for use as drugs, and
1210-432: A large endosperm nucleus which is triploid . Following the formation of zygote it begins to grow through nuclear and cellular divisions, called mitosis , eventually becoming a small group of cells. One section of it becomes the embryo , while the other becomes the suspensor; a structure which forces the embryo into the endosperm and is later undetectable. Two small primordia also form at this time, that later become
1331-1336: A mate). In pursuing this attractant from many flowers of the same species, the pollinator transfers pollen to the stigmas—arranged with equally pointed precision—of all of the flowers it visits. Many flowers rely on simple proximity between flower parts to ensure pollination, while others have elaborate designs to ensure pollination and prevent self-pollination . Flowers use animals including: insects ( entomophily ), birds ( ornithophily ), bats ( chiropterophily ), lizards, and even snails and slugs ( malacophilae ). Plants cannot move from one location to another, thus many flowers have evolved to attract animals to transfer pollen between individuals in dispersed populations. Most commonly, flowers are insect-pollinated, known as entomophilous ; literally "insect-loving" in Greek. To attract these insects flowers commonly have glands called nectaries on various parts that attract animals looking for nutritious nectar . Some flowers have glands called elaiophores , which produce oils rather than nectar. Birds and bees have color vision , enabling them to seek out colorful flowers. Some flowers have patterns, called nectar guides , that show pollinators where to look for nectar; they may be visible only under ultraviolet light, which
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#17328491052661452-496: A network called the International Regulatory Cooperation for Herbal Medicines to try to improve the quality of medical products made from medicinal plants and the claims made for them. In 2015, only around 20% of countries had well-functioning regulatory agencies, while 30% had none, and around half had limited regulatory capacity. In India, where Ayurveda has been practised for centuries, herbal remedies are
1573-458: A noticeable scent. Because of this, plants typically have many thousands of tiny flowers which have comparatively large, feathery stigmas; to increase the chance of pollen being received. Whereas the pollen of entomophilous flowers is usually large, sticky, and rich in protein (to act as a "reward" for pollinators), anemophilous flower pollen is typically small-grained, very light, smooth, and of little nutritional value to insects . In order for
1694-470: A plant can interpret important endogenous and environmental cues such as changes in levels of plant hormones and seasonable temperature and photoperiod changes. Many perennial and most biennial plants require vernalization to flower. The molecular interpretation of these signals is through the transmission of a complex signal known as florigen , which involves a variety of genes , including Constans, Flowering Locus C, and Flowering Locus T. Florigen
1815-431: A policy on traditional medicine in 1991, and since then has published guidelines for them, with a series of monographs on widely used herbal medicines. Medicinal plants may provide three main kinds of benefit: health benefits to the people who consume them as medicines; financial benefits to people who harvest, process, and distribute them for sale; and society-wide benefits, such as job opportunities, taxation income, and
1936-423: A pure chemical. Extraction can be practical when the compound in question is complex. Plant medicines are in wide use around the world. In most of the developing world, especially in rural areas, local traditional medicine , including herbalism, is the only source of health care for people, while in the developed world , alternative medicine including use of dietary supplements is marketed aggressively using
2057-588: A result, phytochemicals have frequently proven unsuitable as the lead substances in drug discovery . In the United States over the period 1999 to 2012, despite several hundred applications for new drug status , only two botanical drug candidates had sufficient evidence of medicinal value to be approved by the Food and Drug Administration . The pharmaceutical industry has remained interested in mining traditional uses of medicinal plants in its drug discovery efforts. Of
2178-404: A sonar-reflecting petal above its flowers, which helps the bat find them, and one species, the cactus Espostoa frutescens , has flowers that are surrounded by an area of sound-absorbent and woolly hairs called the cephalium, which absorbs the bat's ultrasound instead. Flowers are also specialized in shape and have an arrangement of the stamens that ensures that pollen grains are transferred to
2299-401: A substance first discovered in a medicinal plant began with salicylic acid in 1853. Around the end of the 19th century, the mood of pharmacy turned against medicinal plants, as enzymes often modified the active ingredients when whole plants were dried, and alkaloids and glycosides purified from plant material started to be preferred. Drug discovery from plants continued to be important through
2420-410: A succession of medicinal plants, starting with morphine from the poppy in 1806, and soon followed by ipecacuanha and strychnos in 1817, quinine from the cinchona tree, and then many others. As chemistry progressed, additional classes of potentially active substances were discovered in plants. Commercial extraction of purified alkaloids including morphine began at Merck in 1826. Synthesis of
2541-407: A third in 1944. Knuth named his two groups 'Hyphydrogamy' and the more common 'Ephydrogamy'. In hyphydrogamy pollination occurs below the surface of the water and so the pollen grains are typically negatively buoyant . For marine plants that exhibit this method, the stigmas are usually stiff, while freshwater species have small and feathery stigmas. In ephydrogamy pollination occurs on the surface of
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#17328491052662662-435: A whole is better prepared for an adverse occurrence in the environment. Cross-pollination, therefore, increases the survival of the species and is usually preferred by flowers for this reason. The principal adaptive function of flowers is the promotion of cross-pollination or outcrossing, a process that allows the masking of deleterious mutations in the genome of progeny. The masking effect of outcrossing sexual reproduction
2783-416: Is a loss of B gene function, mutant flowers are produced with sepals in the first whorl as usual, but also in the second whorl instead of the normal petal formation. In the third whorl, the lack of the B function but the presence of the C function mimics the fourth whorl, leading to the formation of carpels also in the third whorl. The principal purpose of a flower is the reproduction of the individual and
2904-422: Is a much rarer method, occurring in only around 2% of abiotically pollinated flowers. Common examples of this include Calitriche autumnalis , Vallisneria spiralis and some sea-grasses . One characteristic which most species in this group share is a lack of an exine , or protective layer, around the pollen grain. Paul Knuth identified two types of hydrophilous pollination in 1906 and Ernst Schwarzenbach added
3025-417: Is a way to represent the structure of a flower using specific letters, numbers, and symbols, presenting substantial information about the flower in a compact form. It can represent a taxon , usually giving ranges of the numbers of different organs, or particular species. Floral formulae have been developed in the early 19th century and their use has declined since. Prenner et al. (2010) devised an extension of
3146-433: Is an antiseptic and was once used as a vermifuge (anti-worm medicine). Medicinal plants demand intensive management. Different species each require their own distinct conditions of cultivation. The World Health Organization recommends the use of rotation to minimise problems with pests and plant diseases. Cultivation may be traditional or may make use of conservation agriculture practices to maintain organic matter in
3267-404: Is an example of coevolution , as the flower and pollinator have developed together over a long period to match each other's needs. This close relationship compounds the negative effects of extinction , however, since the extinction of either member in such a relationship would almost certainly mean the extinction of the other member as well. Flowers that use abiotic, or non-living, vectors use
3388-427: Is because it is directly connected to the method of seed dispersal; that being the purpose of fruit - to encourage or enable the seed's dispersal and protect the seed while doing so. Following the pollination of a flower, fertilization, and finally the development of a seed and fruit, a mechanism is typically used to disperse the fruit away from the plant. In Angiosperms (flowering plants) seeds are dispersed away from
3509-656: Is from the Middle English flour , which referred to both the ground grain and the reproductive structure in plants, before splitting off in the 17th century. It comes originally from the Latin name of the Italian goddess of flowers, Flora . The early word for flower in English was blossom , though it now refers to flowers only of fruit trees . The morphology of a flower, or its form and structure, can be considered in two parts:
3630-541: Is highly reduced or absent). The stem or stalk subtending a flower, or an inflorescence of flowers, is called a peduncle . If a peduncle supports more than one flower, the stems connecting each flower to the main axis are called pedicels . The apex of a flowering stem forms a terminal swelling which is called the torus or receptacle. In the majority of species, individual flowers have both carpels and stamens. These flowers are described by botanists as being perfect, bisexual, or hermaphrodite . In some species of plants,
3751-402: Is increasing in developed countries. This brings attendant risks of toxicity and other effects on human health, despite the safe image of herbal remedies. Herbal medicines have been in use since long before modern medicine existed; there was and often still is little or no knowledge of the pharmacological basis of their actions, if any, or of their safety. The World Health Organization formulated
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3872-494: Is known as "genetic complementation". This beneficial effect of outcrossing on progeny is also recognized as hybrid vigour or heterosis. Once outcrossing is established due to the benefits of genetic complementation, subsequent switching to inbreeding becomes disadvantageous because it allows the expression of the previously masked deleterious recessive mutations, usually referred to as inbreeding depression. Charles Darwin in his 1889 book The Effects of Cross and Self-Fertilization in
3993-593: Is no reason to presume that because a product comes from nature it must be safe: the existence of powerful natural poisons like atropine and nicotine shows this to be untrue. Further, the high standards applied to conventional medicines do not always apply to plant medicines, and dose can vary widely depending on the growth conditions of plants: older plants may be much more toxic than young ones, for instance. Plant extracts may interact with conventional drugs, both because they may provide an increased dose of similar compounds, and because some phytochemicals interfere with
4114-408: Is only one type of stamen, but there are plant species where the flowers have two types; a "normal" one and one with anthers that produce sterile pollen meant to attract pollinators. The gynoecium , or the carpels , is the female part of the flower found on the innermost whorl. Each carpel consists of a stigma , which receives pollen, a style , which acts as a stalk, and an ovary , which contains
4235-443: Is preferred because it allows for genetic variation , which contributes to the survival of the species. Many flowers depend on external factors for pollination, such as the wind, water, animals, and especially insects . Larger animals such as birds, bats, and even some pygmy possums , however, can also be employed. To accomplish this, flowers have specific designs which encourage the transfer of pollen from one plant to another of
4356-429: Is produced in the leaves in reproductively favorable conditions and acts in buds and growing tips to induce several different physiological and morphological changes. The first step of the transition is the transformation of the vegetative stem primordia into floral primordia. This occurs as biochemical changes take place to change the cellular differentiation of leaf, bud and stem tissues into tissue that will grow into
4477-572: Is reflected morphologically in the presence of more pulp , an aril , and sometimes an elaiosome (primarily for ants), which are other fleshy structures. Medicinal plants Medicinal plants , also called medicinal herbs , have been discovered and used in traditional medicine practices since prehistoric times. Plants synthesize hundreds of chemical compounds for various functions, including defense and protection against insects , fungi , diseases , and herbivorous mammals . The earliest historical records of herbs are found from
4598-418: Is typically another part. In some families, such as the grasses , the petals are greatly reduced; in many species, the sepals are colorful and petal-like. Other flowers have modified petal-like stamens; the double flowers of peonies and roses are mostly petaloid stamens. Many flowers have symmetry. When the perianth is bisected through the central axis from any point and symmetrical halves are produced,
4719-574: Is visible to bees and some other insects. Flowers also attract pollinators by scent , though not all flower scents are appealing to humans; several flowers are pollinated by insects that are attracted to rotten flesh and have flowers that smell like dead animals. These are often called carrion flowers , including plants in the genus Rafflesia , and the titan arum . Flowers pollinated by night visitors, including bats and moths, are likely to concentrate on scent to attract pollinators and so most such flowers are white. Some plants pollinated by bats have
4840-577: The Sumerian civilization, where hundreds of medicinal plants including opium are listed on clay tablets, c. 3000 BC . The Ebers Papyrus from ancient Egypt , c. 1550 BC , describes over 850 plant medicines. The Greek physician Dioscorides , who worked in the Roman army, documented over 1000 recipes for medicines using over 600 medicinal plants in De materia medica , c. 60 AD ; this formed
4961-400: The anthers . The female gametophytes are contained within the ovules produced in the ovary . Most flowering plants depend on animals, such as bees, moths, and butterflies, to transfer their pollen between different flowers, and have evolved to attract these pollinators by various strategies, including brightly colored, conspicuous petals, attractive scents, and the production of nectar ,
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5082-549: The apothecary shops of Europe in the 1800s, where pharmacists provided local traditional medicines to customers, which included extracts like morphine, quinine, and strychnine. Therapeutically important drugs like camptothecin (from Camptotheca acuminata , used in traditional Chinese medicine) and taxol (from the Pacific yew, Taxus brevifolia ) were derived from medicinal plants. The Vinca alkaloids vincristine and vinblastine , used as anti-cancer drugs, were discovered in
5203-414: The calyx , corolla , androecium , and gynoecium . Together the calyx and corolla make up the non-reproductive part of the flower called the perianth , and in some cases may not be differentiated. If this is the case, then they are described as tepals . The sepals , collectively called the calyx, are modified leaves that occur on the outermost whorl of the flower. They are leaf-like, in that they have
5324-494: The cotyledon , which is used as an energy store. Plants which grow out one of these primordia are called monocotyledons , while those that grow out two are dicotyledons . The next stage is called the Torpedo stage and involves the growth of several key structures, including: the radicle (embryotic root), the epicotyl (embryotic stem), and the hypocotyl , (the root/shoot junction). In the final step vascular tissue develops around
5445-439: The gizzard of animals or even to germinate better after passing through them. They can be eaten by birds ( ornithochory) , bats ( chiropterochory) , rodents , primates, ants ( myrmecochory ), non-bird sauropsids ( saurochory) , mammals in general (mammaliochory) , and even fish . Typically their fruit are fleshy, have a high nutritional value, and may have chemical attractants as an additional "reward" for dispersers. This
5566-518: The wind or, much less commonly, water , to move pollen from one flower to the next. In wind-dispersed ( anemophilous ) species, the tiny pollen grains are carried, sometimes many thousands of kilometers, by the wind to other flowers. Common examples include the grasses , birch trees , along with many other species in the order Fagales , ragweeds , and many sedges . They do not need to attract pollinators and therefore tend not to grow large, showy, or colorful flowers, and do not have nectaries, nor
5687-524: The "Circa Instans," which served as practical guides for herbal remedies. In the Iberian Peninsula, the regions of the North remained independent during the period of Islamic occupation, and retained their traditional and indigenous medical practices. Galicia and Asturias, possessed a rich herbal heritage shaped by its Celtic and Roman influences. The Galician people were known for their strong connection to
5808-579: The 1073 small-molecule drugs approved in the period 1981 to 2010, over half were either directly derived from or inspired by natural substances. Among cancer treatments, of 185 small-molecule drugs approved in the period from 1981 to 2019, 65% were derived from or inspired by natural substances. Plant medicines can cause adverse effects and even death, whether by side-effects of their active substances, by adulteration or contamination, by overdose, or by inappropriate prescription. Many such effects are known, while others remain to be explored scientifically. There
5929-507: The 1950s from the Madagascar periwinkle, Catharanthus roseus . Hundreds of compounds have been identified using ethnobotany , investigating plants used by indigenous peoples for possible medical applications. Some important phytochemicals, including curcumin , epigallocatechin gallate , genistein and resveratrol are pan-assay interference compounds , meaning that in vitro studies of their activity often provide unreliable data. As
6050-404: The 20th century and into the 21st, with important anti-cancer drugs from yew and Madagascar periwinkle . Medicinal plants are used with the intention of maintaining health, to be administered for a specific condition, or both, whether in modern medicine or in traditional medicine . The Food and Agriculture Organization estimated in 2002 that over 50,000 medicinal plants are used across
6171-529: The Brazilian Amazon, assisted by researchers, have described 101 plant species used for traditional medicines. Drugs derived from plants including opiates, cocaine and cannabis have both medical and recreational uses . Different countries have at various times made use of illegal drugs , partly on the basis of the risks involved in taking psychoactive drugs . Plant medicines have often not been tested systematically, but have come into use informally over
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#17328491052666292-507: The COVID-19 pandemic, which led to the United States taking action to stop the deceptive marketing of herbal products to combat the virus. Where medicinal plants are harvested from the wild rather than cultivated, they are subject to both general and specific threats. General threats include climate change and habitat loss to development and agriculture. A specific threat is over-collection to meet rising demand for medicines. A case in point
6413-600: The Catalonia region of northeastern Spain, was a hub of cultural exchange during the Middle Ages, fostering the preservation and dissemination of medical knowledge. Catalan herbalists, known as "herbolarios," compiled manuscripts detailing the properties and uses of medicinal plants found in the region. The University of Barcelona, founded in 1450, played a pivotal role in advancing herbal medicine through its botanical gardens and academic pursuits. In Scotland and England, herbalism
6534-547: The Elder's "Naturalis Historia" contains valuable insights into Roman medical plant practices Among the Celtic peoples of ancient Europe, herbalism played a vital role in both medicine and spirituality. Druids, the religious leaders of the Celts, were reputed to possess deep knowledge of plants and their medicinal properties. Although written records are scarce, archaeological evidence, such as
6655-742: The Indomalaya region, including Michelia figo , M. doltsopa , and M. champaca. The genus is named after the Florentine botanist Pietro Antonio Micheli (1679–1737). They grow to the height of 10–45 metres Morphological data and molecular data recently showed that the genus Michelia is very closely related to subgenus Yulania of genus Magnolia . Many botanists now treat the genus Michelia accordingly. New combinations of names have been provided for. For further information see under genus Magnolia . Some species formerly placed in Michelia include
6776-677: The Islamic world, particularly in Baghdad and in Al-Andalus . Among many works on medicinal plants, Abulcasis (936–1013) of Cordoba wrote The Book of Simples , and Ibn al-Baitar (1197–1248) recorded hundreds of medicinal herbs such as Aconitum , nux vomica , and tamarind in his Corpus of Simples . Avicenna included many plants in his 1025 The Canon of Medicine . Abu-Rayhan Biruni , Ibn Zuhr , Peter of Spain , and John of St Amand wrote further pharmacopoeias . The Early Modern period saw
6897-627: The Old World and the Americas in the 15th and 16th centuries. Medicinal herbs arriving in the Americas included garlic, ginger, and turmeric; coffee, tobacco and coca travelled in the other direction. In Mexico, the sixteenth century Badianus Manuscript described medicinal plants available in Central America. The place of plants in medicine was radically altered in the 19th century by the application of chemical analysis . Alkaloids were isolated from
7018-541: The Romans, Celts, and Nordic peoples, also practiced herbal medicine as a significant component of their healing traditions. The Romans had a rich tradition of herbal medicine, drawing upon knowledge inherited from the Greeks and expanding upon it. Notable works include those of Pedanius Dioscorides, whose "De Materia Medica" served as a comprehensive guide to medicinal plants and remained influential for centuries. Additionally, Pliny
7139-462: The Vegetable Kingdom at the beginning of chapter XII noted, "The first and most important of the conclusions which may be drawn from the observations given in this volume, is that generally cross-fertilisation is beneficial and self-fertilisation often injurious, at least with the plants on which I experimented." Self-pollination is the pollination of the carpel of a flower by pollen from either
7260-484: The apical meristem, which becomes a whorl of sepals. In the second whorl, both A and B genes are expressed, leading to the formation of petals. In the third whorl, B and C genes interact to form stamens and in the center of the flower C genes alone give rise to carpels. The model is based upon studies of aberrant flowers and mutations in Arabidopsis thaliana and the snapdragon, Antirrhinum majus . For example, when there
7381-524: The astringent rind of the pomegranate , containing polyphenols called punicalagins , is used as a medicine, with no scientific proof of efficacy. Terpenes and terpenoids of many kinds are found in a variety of medicinal plants, and in resinous plants such as the conifers . They are strongly aromatic and serve to repel herbivores. Their scent makes them useful in essential oils , whether for perfumes such as rose and lavender , or for aromatherapy . Some have medicinal uses: for example, thymol
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#17328491052667502-716: The basis of pharmacopoeias for some 1500 years. Drug research sometimes makes use of ethnobotany to search for pharmacologically active substances, and this approach has yielded hundreds of useful compounds. These include the common drugs aspirin , digoxin , quinine , and opium . The compounds found in plants are diverse, with most in four biochemical classes: alkaloids , glycosides , polyphenols , and terpenes . Few of these are scientifically confirmed as medicines or used in conventional medicine. Medicinal plants are widely used as folk medicine in non-industrialized societies, mainly because they are readily available and cheaper than modern medicines. The annual global export value of
7623-582: The bodies of the pollinator when it lands in search of its attractant. Other flowers use mimicry or pseudocopulation to attract pollinators. Many orchids, for example, produce flowers resembling female bees or wasps in color, shape, and scent. Males move from one flower to the next in search of a mate, pollinating the flowers. Many flowers have close relationships with one or a few specific pollinating organisms. Many flowers, for example, attract only one specific species of insect and therefore rely on that insect for successful reproduction. This close relationship
7744-737: The body's systems that metabolise drugs in the liver including the cytochrome P450 system, making the drugs last longer in the body and have a cumulative effect. Plant medicines can be dangerous during pregnancy. Since plants may contain many different substances, plant extracts may have complex effects on the human body. Herbal medicine and dietary supplement products have been criticized as not having sufficient standards or scientific evidence to confirm their contents, safety, and presumed efficacy. Companies often make false claims about their herbal products promising health benefits that aren't backed by evidence to generate more sales. The market for dietary supplements and nutraceuticals grew by 5% during
7865-410: The centuries. By 2007, clinical trials had demonstrated potentially useful activity in nearly 16% of herbal extracts; there was limited in vitro or in vivo evidence for roughly half the extracts; there was only phytochemical evidence for around 20%; 0.5% were allergenic or toxic; and some 12% had basically never been studied scientifically. Cancer Research UK caution that there is no reliable evidence for
7986-614: The claims of traditional medicine. As of 2015, most products made from medicinal plants had not been tested for their safety and efficacy, and products that were marketed in developed economies and provided in the undeveloped world by traditional healers were of uneven quality, sometimes containing dangerous contaminants. Traditional Chinese medicine makes use of a wide variety of plants, among other materials and techniques. Researchers from Kew Gardens found 104 species used for diabetes in Central America, of which seven had been identified in at least three separate studies. The Yanomami of
8107-517: The collective cluster of flowers is called an inflorescence . Some inflorescences are composed of many small flowers arranged in a formation that resembles a single flower. A common example of this is most members of the very large composite ( Asteraceae ) group. A single daisy or sunflower , for example, is not a flower but a flower head —an inflorescence composed of numerous flowers (or florets). An inflorescence may include specialized stems and modified leaves known as bracts . A floral formula
8228-415: The content and known pharmacological activity of these substances in medicinal plants is the scientific basis for their use in modern medicine, if scientifically confirmed. For instance, daffodils ( Narcissus ) contain nine groups of alkaloids including galantamine , licensed for use against Alzheimer's disease . The alkaloids are bitter-tasting and toxic, and concentrated in the parts of the plant such as
8349-518: The discovery of medicinal plants at Celtic sites, provides insight into their herbal practices In the Nordic regions, including Scandinavia and parts of Germany, herbal medicine was also prevalent in ancient times. The Norse sagas and Eddic poetry often mention the use of herbs for healing purposes. Additionally, archaeological findings, such as the remains of medicinal plants in Viking-age graves, attest to
8470-558: The effectiveness of herbal remedies for cancer. A 2012 phylogenetic study built a family tree down to genus level using 20,000 species to compare the medicinal plants of three regions, Nepal, New Zealand and the Cape of South Africa. It discovered that the species used traditionally to treat the same types of condition belonged to the same groups of plants in all three regions, giving a "strong phylogenetic signal". Since many plants that yield pharmaceutical drugs belong to just these groups, and
8591-484: The existing model to broaden the descriptive capability of the formula. The format of floral formulae differs in different parts of the world, yet they convey the same information. The structure of a flower can also be expressed by the means of floral diagrams . The use of schematic diagrams can replace long descriptions or complicated drawings as a tool for understanding both floral structure and evolution. Such diagrams may show important features of flowers, including
8712-524: The flourishing of illustrated herbals across Europe, starting with the 1526 Grete Herball . John Gerard wrote his famous The Herball or General History of Plants in 1597, based on Rembert Dodoens , and Nicholas Culpeper published his The English Physician Enlarged . Many new plant medicines arrived in Europe as products of Early Modern exploration and the resulting Columbian Exchange , in which livestock, crops and technologies were transferred between
8833-413: The flower is said to be actinomorphic or regular. This is an example of radial symmetry . When flowers are bisected and produce only one line that produces symmetrical halves, the flower is said to be irregular or zygomorphic . If, in rare cases, they have no symmetry at all they are called asymmetric. Flowers may be directly attached to the plant at their base ( sessile —the supporting stalk or stem
8954-497: The flower's stigma. This pollination does not require an investment from the plant to provide nectar and pollen as food for pollinators. Some flowers produce diaspores without fertilization ( parthenocarpy ). After fertilization, the ovary of the flower develops into fruit containing seeds . Flowers have long been appreciated for their beauty and pleasant scents, and also hold cultural significance as religious, ritual, or symbolic objects, or sources of medicine and food. Flower
9075-511: The flowers are imperfect or unisexual: having only either male (stamen) or female (carpel) parts. If unisexual male and female flowers appear on the same plant, the species is called monoecious . However, if an individual plant is either female or male, the species is called dioecious . Many flowers have nectaries , which are glands that produce a sugary fluid used to attract pollinators. They are not considered as an organ on their own. In those species that have more than one flower on an axis,
9196-424: The following two broad groups of pollination methods: Flowers that use biotic vectors attract and use insects , bats , birds , or other animals to transfer pollen from one flower to the next. Often they are specialized in shape and have an arrangement of the stamens that ensures that pollen grains are transferred to the bodies of the pollinator when it lands in search of its attractant (such as nectar, pollen, or
9317-652: The following. Synonyms are from Plants of the World Online , as of March 2022. Flower A flower , also known as a bloom or blossom , is the reproductive structure found in flowering plants (plants of the division Angiospermae ). Flowers consist of a combination of vegetative organs – sepals that enclose and protect the developing flower. These petals attract pollinators, and reproductive organs that produce gametophytes , which in flowering plants produce gametes . The male gametophytes, which produce sperm, are enclosed within pollen grains produced in
9438-451: The gametophytes also develop inside the spores, i.e., they are endosporic. Since the flowers are the reproductive organs of the plant, they mediate the joining of the sperm, contained within pollen, to the ovules — contained in the ovary. Pollination is the movement of pollen from the anthers to the stigma. Normally pollen is moved from one plant to another, known as cross-pollination , but many plants can self-pollinate. Cross-pollination
9559-452: The groups were independently used in three different world regions, the results were taken to mean 1) that these plant groups do have potential for medicinal efficacy, 2) that undefined pharmacological activity is associated with use in traditional medicine, and 3) that the use of a phylogenetic groups for possible plant medicines in one region may predict their use in the other regions. The World Health Organization (WHO) has been coordinating
9680-648: The importance of herbal remedies in Nordic culture From ancient times to the present, Ayurvedic medicine as documented in the Atharva Veda , the Rig Veda and the Sushruta Samhita has used hundreds of herbs and spices, such as turmeric , which contains curcumin . The Chinese pharmacopoeia , the Shennong Ben Cao Jing records plant medicines such as chaulmoogra for leprosy, ephedra , and hemp . This
9801-437: The land and nature and preserved botanical knowledge, with healers, known as "curandeiros" or "meigas," who relied on local plants for healing purposes The Asturian landscape, characterized by lush forests and mountainous terrain, provided a rich source of medicinal herbs used in traditional healing practices, with "yerbatos," who possessed extensive knowledge of local plants and their medicinal properties Barcelona, located in
9922-445: The leaves, rather than singly at the branch ends as Magnolia does. Several of the larger species are locally important sources of timber . Some species, including the champak ( Michelia champaca ) and Michelia doltsopa are grown for their flowers, both on the tree and as cut flowers. Champak flowers are also used to produce an essential oil for perfume. A few species have been introduced to gardens or as street trees outside of
10043-463: The majority of what are often informal attempted treatments, not tested scientifically. The World Health Organization estimates, without reliable data, that some 80 percent of the world's population depends mainly on traditional medicine (including but not limited to plants); perhaps some two billion people are largely reliant on medicinal plants. The use of plant-based materials including herbal or natural health products with supposed health benefits,
10164-491: The original source of most plant medicines. Human settlements are often surrounded by weeds used as herbal medicines , such as nettle , dandelion and chickweed . Humans were not alone in using herbs as medicines: some animals such as non-human primates , monarch butterflies and sheep ingest medicinal plants when they are ill. Plant samples from prehistoric burial sites are among the lines of evidence that Paleolithic peoples had knowledge of herbal medicine. For instance,
10285-400: The ovary. After penetrating the center-most part of the ovary it enters the egg apparatus and into one synergid . At this point the end of the pollen tube bursts and releases the two sperm cells, one of which makes its way to an egg, while also losing its cell membrane and much of its protoplasm . The sperm's nucleus then fuses with the egg's nucleus, resulting in the formation of a zygote ,
10406-504: The ovule is fertilized by pollen from the same flower or plant, occurs in flowers that always self-fertilize, such as many dandelions . Some flowers are self-pollinated and have flowers that never open or are self-pollinated before the flowers open; these flowers are called cleistogamous ; many species in the genus Viola exhibit this, for example. Conversely, many species of plants have ways of preventing self-pollination and hence, self-fertilization. Unisexual male and female flowers on
10527-524: The ovules. Carpels may occur in one to several whorls, and when fused are often described as a pistil . Inside the ovary, the ovules are attached to the placenta by structures called funiculi . Although this arrangement is considered "typical", plant species show a wide variation in floral structure. The four main parts of a flower are generally defined by their positions on the receptacle and not by their function. Many flowers lack some parts or parts may be modified into other functions or look like what
10648-534: The perianth. They are often delicate and thin and are usually colored, shaped, or scented to encourage pollination. Although similar to leaves in shape, they are more comparable to stamens in that they form almost simultaneously with one another, but their subsequent growth is delayed. If the corolla is fused together it is called sympetalous. The androecium , or stamens, is the whorl of pollen-producing male parts. Stamens consist typically of an anther , made up of four pollen sacs arranged in two thecae , connected to
10769-417: The plant material in cold wine or distilled spirit to form a tincture . Traditional poultices were made by boiling medicinal plants, wrapping them in a cloth, and applying the resulting parcel externally to the affected part of the body. When modern medicine has identified a drug in a medicinal plant, commercial quantities of the drug may either be synthesised or extracted from plant material, yielding
10890-451: The plant so as to not force competition between the mother and the daughter plants, as well as to enable the colonization of new areas. They are often divided into two categories, though many plants fall in between or in one or more of these: In allochory, plants use an external vector , or carrier, to transport their seeds away from them. These can be either biotic (living), such as by birds and ants, or abiotic (non-living), such as by
11011-606: The practice of medieval medicine, which combined elements of Ancient Greek and Roman traditions. Catholic monastic orders played a significant role in preserving and expanding herbal knowledge. Manuscripts like the "Tractatus de Herbis" from the 15th century depict French herbal remedies and their uses. Monasteries and convents served as centers of learning, where monks and nuns cultivated medicinal gardens. Likewise, in Italy, herbalism flourished with contribution Italian physicians like Matthaeus Platearius who compiled herbal manuscripts, such as
11132-451: The preparation of herbal medicines include decoction , powdering, and extraction with alcohol, in each case yielding a mixture of substances. Decoction involves crushing and then boiling the plant material in water to produce a liquid extract that can be taken orally or applied topically. Powdering involves drying the plant material and then crushing it to yield a powder that can be compressed into tablets . Alcohol extraction involves soaking
11253-400: The process of pollination. Fertilization , also called Synagmy, occurs following pollination, which is the movement of pollen from the stamen to the carpel. It encompasses both plasmogamy , the fusion of the protoplasts , and karyogamy , the fusion of the nuclei . When pollen lands on the stigma of the flower it begins creating a pollen tube which runs down through the style and into
11374-600: The relative positions of the various organs, including the presence of fusion and symmetry, as well as structural details. A flower develops on a modified shoot or axis from a determinate apical meristem ( determinate meaning the axis grows to a set size). It has compressed internodes, bearing structures that in classical plant morphology are interpreted as highly modified leaves . Detailed developmental studies, however, have shown that stamens are often initiated more or less like modified stems (caulomes) that in some cases may even resemble branchlets . Taking into account
11495-420: The reproductive organs. Growth of the central part of the stem tip stops or flattens out and the sides develop protuberances in a whorled or spiral fashion around the outside of the stem end. These protuberances develop into the sepals, petals, stamens, and carpels . Once this process begins, in most plants, it cannot be reversed and the stems develop flowers, even if the initial start of the flower formation event
11616-497: The responsibility of a government department, AYUSH , under the Ministry of Health & Family Welfare. WHO has set out a strategy for traditional medicines with four objectives: to integrate them as policy into national healthcare systems; to provide knowledge and guidance on their safety, efficacy, and quality; to increase their availability and affordability; and to promote their rational, therapeutically sound usage. WHO notes in
11737-490: The same flower or another flower on the same plant, leading to the creation of a genetic clone through asexual reproduction . This increases the reliability of producing seeds, the rate at which they can be produced, and lowers the amount energy needed. But, most importantly, it limits genetic variation . In addition, self-pollination causes inbreeding depression , due largely to the expression of recessive deleterious mutations . The extreme case of self-fertilization, when
11858-412: The same plant may not appear or mature at the same time, or pollen from the same plant may be incapable of fertilizing its ovules. The latter flower types, which have chemical barriers to their own pollen, are referred to as self-incompatible. In Clianthus puniceus , self-pollination is used strategically as an "insurance policy". When a pollinator, in this case a bird, visits C. puniceus , it rubs off
11979-769: The same species. The period during which this process can take place (when the flower is fully expanded and functional) is called anthesis , hence the study of pollination biology is called anthecology . Flowering plants usually face evolutionary pressure to optimize the transfer of their pollen , and this is typically reflected in the morphology of the flowers and the behavior of the plants. Pollen may be transferred between plants via several 'vectors,' or methods. Around 80% of flowering plants make use of biotic or living vectors. Others use abiotic, or non-living, vectors and some plants make use of multiple vectors, but most are highly specialized. Though some fit between or outside of these groups, most flowers can be divided between
12100-482: The seed. The ovary, inside which the seed is forming from the ovule, grows into a fruit . All the other main floral parts die during this development, including: the style, stigma, sepals, stamens, and petals. The fruit contains three structures: the exocarp , or outer layer, the mesocarp , or the fleshy part, and the endocarp , or innermost layer, while the fruit wall is called the pericarp . The size, shape, toughness, and thickness varies among different fruit. This
12221-632: The seventeenth century. During the Middle Ages, herbalism continued to flourish across Europe, with distinct traditions emerging in various regions, often influenced by cultural, religious, indigenous, and geographical factors. In the Early Middle Ages , Benedictine monasteries preserved medical knowledge in Europe , translating and copying classical texts and maintaining herb gardens . Hildegard of Bingen wrote Causae et Curae ("Causes and Cures") on medicine. In France, herbalism thrived alongside
12342-485: The soil and to conserve water, for example with no-till farming systems. In many medicinal and aromatic plants, plant characteristics vary widely with soil type and cropping strategy, so care is required to obtain satisfactory yields. Medicinal plants are often tough and fibrous, requiring some form of preparation to make them convenient to administer. According to the Institute for Traditional Medicine, common methods for
12463-439: The species. All flowering plants are heterosporous , that is, every individual plant produces two types of spores . Microspores are produced by meiosis inside anthers and megaspores are produced inside ovules that are within an ovary. Anthers typically consist of four microsporangia and an ovule is an integumented megasporangium. Both types of spores develop into gametophytes inside sporangia. As with all heterosporous plants,
12584-402: The specific threat of over-collection to meet market demand. Plants, including many now used as culinary herbs and spices , have been used as medicines, not necessarily effectively, from prehistoric times. Spices have been used partly to counter food spoilage bacteria, especially in hot climates, and especially in meat dishes that spoil more readily. Angiosperms ( flowering plants ) were
12705-823: The stem most likely to be eaten by herbivores; they may also protect against parasites . Modern knowledge of medicinal plants is being systematised in the Medicinal Plant Transcriptomics Database, which by 2011 provided a sequence reference for the transcriptome of some thirty species. Major classes of plant phytochemicals are described below, with examples of plants that contain them. Alkaloids are bitter-tasting chemicals, very widespread in nature, and often toxic, found in many medicinal plants. There are several classes with different modes of action as drugs, both recreational and pharmaceutical. Medicines of different classes include atropine , scopolamine , and hyoscyamine (all from nightshade ),
12826-428: The stigmatic covering and allows for pollen from the bird to enter the stigma. If no pollinators visit, however, then the stigmatic covering falls off naturally to allow for the flower's own anthers to pollinate the flower through self-pollination. Pollen is a large contributor to asthma and other respiratory allergies which combined affect between 10 and 50% of people worldwide. This number appears to be growing, as
12947-404: The strategy that countries are experiencing seven challenges to such implementation, namely in developing and enforcing policy; in integration; in safety and quality, especially in assessment of products and qualification of practitioners; in controlling advertising; in research and development; in education and training; and in the sharing of information. The pharmaceutical industry has roots in
13068-463: The temperature increases due to climate change mean that plants are producing more pollen , which is also more allergenic. Pollen is difficult to avoid, however, because of its small size and prevalence in the natural environment. Most of the pollen which causes allergies is that produced by wind-dispersed pollinators such as the grasses , birch trees , oak trees, and ragweeds ; the allergens in pollen are proteins which are thought to be necessary in
13189-666: The thousands of types of plants with medicinal properties was estimated to be US$ 60 billion per year and growing at the rate of 6% per annum. In many countries, there is little regulation of traditional medicine, but the World Health Organization coordinates a network to encourage safe and rational use. The botanical herbal market has been criticized for being poorly regulated and containing placebo and pseudoscience products with no scientific research to support their medical claims. Medicinal plants face both general threats, such as climate change and habitat destruction , and
13310-686: The traditional medicine berberine (from plants such as Berberis and Mahonia ), caffeine ( Coffea ), cocaine ( Coca ), ephedrine ( Ephedra ), morphine ( opium poppy ), nicotine ( tobacco ), reserpine ( Rauvolfia serpentina ), quinidine and quinine ( Cinchona ), vincamine ( Vinca minor ), and vincristine ( Catharanthus roseus ). Anthraquinone glycosides are found in medicinal plants such as rhubarb , cascara , and Alexandrian senna . Plant-based laxatives made from such plants include senna , rhubarb and Aloe . The cardiac glycosides are powerful drugs from medicinal plants including foxglove and lily of
13431-796: The valley . They include digoxin and digitoxin which support the beating of the heart, and act as diuretics . Polyphenols of several classes are widespread in plants, having diverse roles in defenses against plant diseases and predators. They include hormone-mimicking phytoestrogens and astringent tannins . Plants containing phytoestrogens have been administered for centuries for gynecological disorders, such as fertility, menstrual, and menopausal problems. Among these plants are Pueraria mirifica , kudzu , angelica , fennel , and anise . Many polyphenolic extracts, such as from grape seeds , olives or maritime pine bark , are sold as dietary supplements and cosmetics without proof or legal health claims for medicinal effects. In Ayurveda ,
13552-428: The vegetative part, consisting of non-reproductive structures such as petals ; and the reproductive or sexual parts. A stereotypical flower is made up of four kinds of structures attached to the tip of a short stalk or axis, called a receptacle . Each of these parts or floral organs is arranged in a spiral called a whorl . The four main whorls (starting from the base of the flower or lowest node and working upwards) are
13673-619: The water and so the pollen has a low density to enable floating, though many also use rafts, and are hydrophobic . Marine flowers have floating thread-like stigmas and may have adaptations for the tide, while freshwater species create indentations in the water. The third category, set out by Schwarzenbach, is those flowers which transport pollen above the water through conveyance. This ranges from floating plants, ( Lemnoideae ), to staminate flowers ( Vallisneria ). Most species in this group have dry, spherical pollen which sometimes forms into larger masses, and female flowers which form depressions in
13794-401: The water; the method of transport varies. Flowers can be pollinated by two mechanisms; cross-pollination and self-pollination. No mechanism is indisputably better than the other as they each have their advantages and disadvantages. Plants use one or both of these mechanisms depending on their habitat and ecological niche . Cross-pollination is the pollination of the carpel by pollen from
13915-480: The whole diversity in the development of the androecium of flowering plants, we find a continuum between modified leaves (phyllomes), modified stems (caulomes), and modified branchlets (shoots). The transition to flowering is one of the major phase changes that a plant makes during its life cycle. The transition must take place at a time that is favorable for fertilization and the formation of seeds , hence ensuring maximal reproductive success. To meet these needs
14036-460: The wind or water. Many plants use biotic vectors to disperse their seeds away from them. This method falls under the umbrella term zoochory , while endozoochory , also known as fruigivory, refers specifically to plants adapted to grow fruit in order to attract animals to eat them. Once eaten they go through typically go through animal's digestive system and are dispersed away from the plant. Some seeds are specially adapted either to last in
14157-419: The wind to effectively pick up and transport the pollen, the flowers typically have anthers loosely attached to the end of long thin filaments, or pollen forms around a catkin which moves in the wind. Rarer forms of this involve individual flowers being moveable by the wind ( pendulous ), or even less commonly; the anthers exploding to release the pollen into the wind. Pollination through water ( hydrophily )
14278-407: The world. The Royal Botanic Gardens, Kew more conservatively estimated in 2016 that 17,810 plant species have a medicinal use, out of some 30,000 plants for which a use of any kind is documented. In modern medicine, around a quarter of the drugs prescribed to patients are derived from medicinal plants, and they are rigorously tested. In other systems of medicine, medicinal plants may constitute
14399-580: Was deeply rooted in folk traditions and influenced by Celtic, Anglo-Saxon, and Norse practices. Herbal knowledge was passed down through generations, often by wise women known as "cunning folk." The "Physicians of Myddfai," a Welsh herbal manuscript from the 13th century, reflects the blending of Celtic and Christian beliefs in herbal medicine. In the Islamic Golden Age , scholars translated many classical Greek texts including Dioscorides into Arabic , adding their own commentaries. Herbalism flourished in
14520-416: Was dependent on some environmental cue. The ABC model is a simple model that describes the genes responsible for the development of flowers. Three gene activities interact in a combinatorial manner to determine the developmental identities of the primordia organ within the floral apical meristem . These gene functions are called A, B, and C. Genes are expressed in only the outer and lower most section of
14641-502: Was expanded in the Tang dynasty Yaoxing Lun . In the fourth century BC, Aristotle 's pupil Theophrastus wrote the first systematic botany text, Historia plantarum . In around 60 AD, the Greek physician Pedanius Dioscorides , working for the Roman army, documented over 1000 recipes for medicines using over 600 medicinal plants in De materia medica . The book remained the authoritative reference on herbalism for over 1500 years, into
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