A poster with twelve species of flowers or clusters of flowers of different families

A flower, also known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Magnoliophyta, also called angiosperms). Alternate meanings See Blossom (disambiguation Blossom is a term given to the Flowers of Stone fruit trees Reproduction is the Biological process by which new individual Organisms are produced The flowering plants or angiosperms ( Angiospermae or Magnoliophyta) are the most widespread group The flowering plants or angiosperms ( Angiospermae or Magnoliophyta) are the most widespread group The biological function of a flower is to mediate the union of male sperm with female ovum in order to produce seeds. The process begins with pollination, is followed by fertilization, leading to the formation and dispersal of the seeds. For the higher plants, seeds are the next generation, and serve as the primary means by which individuals of a species are dispersed across the landscape. The grouping of flowers on a plant are called the inflorescence. An inflorescence is a group or cluster of Flowers arranged on a stem that is composed of a main Branch or a complicated arrangement of branches

In addition to serving as the reproductive organs of flowering plants, flowers have long been admired and used by humans, mainly to beautify their environment but also as a source of food.

Flower specialization and pollination

Each flower has a specific design which best encourages the transfer of its pollen. Pollen is a fine to coarse powder consisting of microgametophytes ( pollen grains) which produce the male Gametes (sperm cells of Cleistogamous flowers are self pollinated, after which, they may or may not open. Cleistogamy or automatic self-pollination describes the trait of certain plants to propagate by using non-opening self-pollinating flowers Many Viola and some Salvia species are known to have these types of flowers.

Entomophilous flowers attract and use insects, bats, birds or other animals to transfer pollen from one flower to the next. See also Pollination syndrome Entomophily is a form of pollination whereby Pollen is distributed by Insects particularly Bees Flowers commonly have glands called nectaries on their various parts that attract these animals. Nectar is a Sugar -rich liquid produced by plants It is produced either by the Flowers in which it attracts pollinating animals or by extrafloral Some flowers have patterns, called nectar guides, that show pollinators where to look for nectar. Nectar guides are patterns seen in some Flowers that guide pollinators to the nectar and Pollen. Flowers also attract pollinators by scent and color. Still other flowers use mimicry to attract pollinators. Some species of orchids, for example, produce flowers resembling female bees in color, shape, and scent. Flowers are also 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 a mate). The stamen ( Plural stamina or stamens, from Latin stamen meaning "thread of the warp " is the male 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.

Anemophilous flowers use the wind to move pollen from one flower to the next, examples include the grasses, Birch trees, Ragweed and Maples. See also Pollination syndrome Anemophily or wind pollination is a form of Pollination whereby Pollen is distributed by Wind They have no need to attract pollinators and therefore tend not to be "showy" flowers. Male and female reproductive organs are generally found in separate flowers, the male flowers having a number of long filaments terminating in exposed stamens, and the female flowers having long, feather-like stigmas. Whereas the pollen of entomophilous flowers tends to be large-grained, sticky, and rich in protein (another "reward" for pollinators), anemophilous flower pollen is usually small-grained, very light, and of little nutritional value to insects. Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl

Morphology

Diagram showing the main parts of a mature flower

The umbrella style flower of the Sarracenia genus. Sarracenia (sæɹəsɛniːɑː/ or /sæɹəsiːniːɑː is a Genus comprising 8 to 11 species of North American Pitcher plants

Flowering plants are heterosporangiate, producing two types of reproductive spores. In Biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions The pollen (male spores) and ovules (female spores) are produced in different organs, but the typical flower is a bisporangiate strobilus in that it contains both organs. Pollen is a fine to coarse powder consisting of microgametophytes ( pollen grains) which produce the male Gametes (sperm cells of Ovule literally means "small egg." In Seed plants the ovule is the structure that gives rise to and contains the female reproductive cells In Biology, an organ ( Latin: organum, "instrument tool" from Greek όργανον - organon "organ instrument

A flower is regarded as a modified stem with shortened internodes and bearing, at its nodes, structures that may be highly modified leaves. A stem is one of two main structural axes of a Vascular plant. A stem is one of two main structural axes of a Vascular plant. In Botany, a leaf is an above-ground Plant organ specialized for Photosynthesis. ^[1] In essence, a flower structure forms on a modified shoot or axis with an apical meristem that does not grow continuously (growth is determinate). A meristem is a tissue in all Plants consisting of undifferentiated cells ( meristematic cells) and found in zones of the plant where growth can take place Flowers may be attached to the plant in a few ways. If the flower has no stem but forms in the axil of a leaf, it is called sessile. When one flower is produced, the stem holding the flower is called a peduncle. In Botany, a peduncle is a stalk supporting an Inflorescence, or after Fecundation a fruit If the peduncle ends with groups of flowers, each stem that holds a flower is called a pedicel. A pedicel is a stem that attaches single Flowers to the main stem of the Inflorescence. The flowering stem forms a terminal end which is called the torus or receptacle. The parts of a flower are arranged in whorls on the torus. The four main parts or whorls (starting from the base of the flower or lowest node and working upwards) are as follows:

• Calyx: the outer whorl of sepals; typically these are green, but are petal-like in some species. A sepal (from Latin separatus "separate" + petalum "petal" is a part of the flower of Angiosperms or flower plants A sepal (from Latin separatus "separate" + petalum "petal" is a part of the flower of Angiosperms or flower plants
• Corolla: the whorl of petals, which are usually thin, soft and colored to attract insects that help the process of pollination. A petal (from Ancient Greek petalon "leaf" "thin plate" regarded as a highly modified leaf is one member or part of the corolla Pollination in angiosperms and Gymnosperms is the process that transfers pollen grains, which contain the male Gametes (sperm to where the female
• Androecium (from Greek andros oikia: man's house): one or two whorls of stamens, each a filament topped by an anther where pollen is produced. The stamen ( Plural stamina or stamens, from Latin stamen meaning "thread of the warp " is the male The stamen ( Plural stamina or stamens, from Latin stamen meaning "thread of the warp " is the male The stamen ( Plural stamina or stamens, from Latin stamen meaning "thread of the warp " is the male Pollen is a fine to coarse powder consisting of microgametophytes ( pollen grains) which produce the male Gametes (sperm cells of Pollen contains the male gametes. A gamete (from Ancient Greek γαμέτης; translated gamete = wife gametes = husband is a cell that fuses with another gamete
• Gynoecium (from Greek gynaikos oikia: woman's house): one or more pistils. A gynoecium (from Ancient Greek gyne, "woman" is the Female reproductive part of a Flower. A gynoecium (from Ancient Greek gyne, "woman" is the Female reproductive part of a Flower. The female reproductive organ is the carpel: this contains an ovary with ovules (which contain female gametes). A gynoecium (from Ancient Greek gyne, "woman" is the Female reproductive part of a Flower. A pistil may consist of a number of carpels merged together, in which case there is only one pistil to each flower, or of a single individual carpel (the flower is then called apocarpous). The sticky tip of the pistil, the stigma, is the receptor of pollen. The supportive stalk, the style becomes the pathway for pollen tubes to grow from pollen grains adhering to the stigma, to the ovules, carrying the reproductive material. The pollen tube of most Seed plants acts as a conduit to transport sperm cells from the Pollen grain, either from the stigma (in Flowering plants

Although the floral structure described above is considered the "typical" structural plan, plant species show a wide variety of modifications from this plan. These modifications have significance in the evolution of flowering plants and are used extensively by botanists to establish relationships among plant species. For example, the two subclasses of flowering plants may be distinguished by the number of floral organs in each whorl: dicotyledons typically having 4 or 5 organs (or a multiple of 4 or 5) in each whorl and monocotyledons having three or some multiple of three. Dicotyledons, or "dicots", is a name for a group of Flowering plants whose Seed typically has two embryonic leaves or Cotyledons There Monocotyledons or monocots are one of two major groups of Flowering plants (angiosperms that are traditionally recognised the other being Dicotyledons The number of carpels in a compound pistil may be only two, or otherwise not related to the above generalization for monocots and dicots.

An example of a perfect flower, this Crateva religiosa flower has both stamens (outer ring) and a pistil (center). The flowering tree Crateva religiosa (syn Crataeva religiosa, Crateva adansonii) is called the sacred garlic pear and temple plant

In the majority of species individual flowers have both pistils and stamens as described above. A gynoecium (from Ancient Greek gyne, "woman" is the Female reproductive part of a Flower. These flowers are described by botanists as being perfect, bisexual, or hermaphrodite. A hermaphrodite is an organism having both male and female reproductive organs However, in some species of plants the flowers are imperfect or unisexual: having only either male (stamens) or female (pistil) parts. In the latter case, if an individual plant is either female or male the species is regarded as dioecious. Plant sexuality covers the wide variety of Sexual reproduction systems found across the Plant kingdom However, where unisexual male and female flowers appear on the same plant, the species is considered monoecious. Plant sexuality covers the wide variety of Sexual reproduction systems found across the Plant kingdom

Additional discussions on floral modifications from the basic plan are presented in the articles on each of the basic parts of the flower. In those species that have more than one flower on an axis—so-called composite flowers—the collection of flowers is termed an inflorescence; this term can also refer to the specific arrangements of flowers on a stem. An inflorescence is a group or cluster of Flowers arranged on a stem that is composed of a main Branch or a complicated arrangement of branches In this regard, care must be exercised in considering what a ‘‘flower’’ is. In botanical terminology, a single daisy or sunflower for example, is not a flower but a flower head—an inflorescence composed of numerous tiny flowers (sometimes called florets). The sunflower ( Helianthus annuus) is an Annual plant in the family Asteraceae and native to the Americas, with a large flowering Each of these flowers may be anatomically as described above. Many flowers have a symmetry, if the perianth is bisected through the central axis from any point, symmetrical halves are produced—the flower is called regular or actinomorphic, e. g. rose or trillium. When flowers are bisected and produce only one line that produces symmetrical halves the flower is said to be irregular or zygomorphic. e. g. snapdragon or most orchids.

Floral formula

A floral formula is a way to represent the structure of a flower using specific letters, numbers, and symbols. Typically, a general formula will be used to represent the flower structure of a plant family rather than a particular species. In Biological classification, family ( Latin The following representations are used:

Ca = calyx (sepal whorl; e. g. Ca⁵ = 5 sepals)
Co = corolla (petal whorl; e. g. , Co^3(x) = petals some multiple of three )
    Z = add if zygomorphic (e. g. , CoZ⁶ = zygomorphic with 6 petals)
A = androecium (whorl of stamens; e. g. , A^∞ = many stamens)
G = gynoecium (carpel or carpels; e. g. , G¹ = monocarpous)

x: to represent a "variable number"
∞: to represent "many"

A floral formula would appear something like this:

Ca⁵Co⁵A^{10 - ∞}G¹

Several additional symbols are sometimes used (see Key to Floral Formulas).

Pollination

Grains of pollen sticking to this bee will be transferred to the next flower it visits

Main article: pollination

The primary purpose of a flower is reproduction. Pollination in angiosperms and Gymnosperms is the process that transfers pollen grains, which contain the male Gametes (sperm to where the female Reproduction is the Biological process by which new individual Organisms are produced Flowers are the reproductive organs and mediate the joining of the sperm contained within pollen to the ovules, normally from one plant to another but many plants also can pollinate their own flowers. The fertilized ovules produce seeds that are the next generation. Sexual reproduction produces genetically unique offspring, allowing for adaptation. An adaptation is a characteristic of an Organism that has been favored by Natural selection and Flowers have specific designs which encourages the transfer of pollen from one plant to another of the same species. Many plants are dependent upon external factors to move pollen between flowers, including the wind and animals, especially insects. Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described Even large animals such as birds, bats, and pygmy possums can be employed. The pygmy possums are species of small Possums that together form the Marsupial family Burramyidae. The period of time during which this process can take place (the flower is fully expanded and functional) is called anthesis.

Attraction methods

Bee orchid evolved to mimic a female bee to attracts male bee pollinators

Plants can not move from one location to another, thus many flowers have evolved to attract animals to transfer pollen between individuals in dispersed populations. The Bee Orchid ( Ophrys apifera) is a perennial, temperate climate species of Orchid generally found growing on semi-dry turf, on limestone eVolution is the third Album by eLDee, it was due to be released in 2008 Flowers that are insect-pollinated are called entomophilous; literally "insect-loving" in Latin. They can be highly modified along with the pollinating insects by co-evolution. In a broad sense biological co-evolution is "the change of a biological object triggered by the change of a related object" Flowers commonly have glands called nectaries on various parts that attract animals looking for nutritious nectar. Nectar is a Sugar -rich liquid produced by plants It is produced either by the Flowers in which it attracts pollinating animals or by extrafloral Birds and bees having color vision, enabling them to seek out "colorful" flowers. Birds ( class Aves) are bipedal endothermic ( Warm-blooded) Vertebrate animals that lay eggs. Bees are flying Insects closely related to Wasps and Ants Bees are a Monophyletic lineage within the superfamily Apoidea Some flowers have patterns, called nectar guides, that show pollinators where to look for nectar; they may be visible only under ultraviolet light, which is visible to bees and some other insects. Nectar guides are patterns seen in some Flowers that guide pollinators to the nectar and Pollen. Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays Flowers also attract pollinators by scent and some of those scents are pleasant to our sense of smell. Not all flower scents are appealing to humans, a number of flowers are pollinated by insects that are attracted to rotten flesh and have flowers that smell like dead animals, often called Carrion flowers including Rafflesia, the titan arum, and the North American pawpaw (Asimina triloba). Carrion flowers or Stinking flowers are flowers that emit an odor that smells like rotting flesh Rafflesia is a Genus of parasitic Flowering plants It was discovered in the Indonesian Rain forest by an Indonesian The titan arum or Amorphophallus titanum (from Ancient Greek amorphos, "without form misshapen" + phallos, " Penis This page refers to the US pawpaw in the genus Asimina. In some other parts of the world the name pawpaw is applied to the unrelated tropical fruit Papaya Flowers pollinated by night visitors, including bats and moths, are likely to concentrate on scent to attract pollinators and most such flowers are white.

Still other flowers use mimicry to attract pollinators. Some species of orchids, for example, produce flowers resembling female bees in color, shape, and scent. Male bees move from one such flower to another in search of a mate.

Pollination mechanism

The pollination mechanism employed by a plant depends on what method of pollination is utilized.

Most flowers can be divided between two broad groups of pollination methods:

Entomophilous: flowers 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 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 flower rely on simple proximity between flower parts to ensure pollination. Others, such as the Sarracenia or lady-slipper orchids, have elaborate designs to ensure pollination while preventing self-pollination. Sarracenia (sæɹəsɛniːɑː/ or /sæɹəsiːniːɑː is a Genus comprising 8 to 11 species of North American Pitcher plants Lady Slippers (aka Lady's Slipper, Lady's-slipper, Ladyslipper) is a term used to describe the orchids in the subfamily Cypripedioidea Self-pollination is a form of Pollination that can occur when a Flower has both Stamen and a Carpel in which the Cultivar or

Anthers detached from a Meadow Foxtail flower.

A grass flower head (Meadow Foxtail) showing the plain coloured flowers with large anthers.

Anemophilous: flowers use the wind to move pollen from one flower to the next, examples include the grasses, Birch trees, Ragweed and Maples. Poaceae or Gramineae is a family in the Class Liliopsida of the flowering plants. They have no need to attract pollinators and therefore tend not to be "showy" flowers. Whereas the pollen of entomophilous flowers tends to be large-grained, sticky, and rich in protein (another "reward" for pollinators), anemophilous flower pollen is usually small-grained, very light, and of little nutritional value to insects, though it may still be gathered in times of dearth. Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described Honeybees and bumblebees actively gather anemophilous corn (maize) pollen, though it is of little value to them. Maize (ˈmeɪz ( Zea mays L. ssp mays) known as corn in some countries is a cereal grain domesticated in Mesoamerica

Some flowers are self pollinated and use flowers that never open or are self pollinated before the flowers open, these flowers are called cleistogamous. Many Viola species and some Salvia have these types of flowers.

Flower-pollinator relationships

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 is often given as an example of coevolution, as the flower and pollinator are thought to have developed together over a long period of time to match each other's needs. In a broad sense biological co-evolution is "the change of a biological object triggered by the change of a related object"

This close relationship compounds the negative effects of extinction. In Biology and Ecology, extinction is the cessation of existence of a Species or group of taxa. The extinction of either member in such a relationship would mean almost certain extinction of the other member as well. Some endangered plant species are so because of shrinking pollinator populations. An endangered species is a population of an organism which is at risk of becoming Extinct because it is either few in numbers or threatened by changing environmental or predation The term Pollinator decline refers to the reduction in abundance of Pollinators in many Ecosystems worldwide during the end of the twentieth century

Fertilization and dispersal

Main article: biological dispersal

In this picture the stamens of the flower are clearly visible. Biological dispersal refers to those processes by which a Species maintains ecosystem

Some flowers with both stamens and a pistil are capable of self-fertilization, which does increase the chance of producing seeds but limits genetic variation. The extreme case of self-fertilization occurs in flowers that always self-fertilize, such as many dandelions. Conversely, many species of plants have ways of preventing self-fertilization. Unisexual male and female flowers on 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-sterile or self-incompatible (see also: Plant sexuality). Plant sexuality covers the wide variety of Sexual reproduction systems found across the Plant kingdom

Evolution

Flowers in Kamakura, Kanagawa, Japan

While land plants have existed for about 425 million years, the first ones reproduced by a simple adaptation of their aquatic counterparts: spores. is a city located in Kanagawa, Japan, about 50 km south-south-west of Tokyo. For a topic outline on this subject see List of basic Japan topics. Plant sexuality covers the wide variety of Sexual reproduction systems found across the Plant kingdom In Biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions In the sea, plants -- and some animals -- can simply scatter out genetic clones of themselves to float away and grow elsewhere. This page refers to the Irish town For other uses see Clones (disambiguation, or Clone Clones (Cluain Eois &ndash ˈkloʊnɪs This is how early plants, such as the modern fern, are thought to have reproduced. But plants soon evolved methods of protecting these copies to deal with drying out and other abuse which is even more likely on land than in the sea. The protection became the seed, though it had not yet evolved the flower. A seed (in some plants referred to as a kernel) is a small embryonic Plant enclosed in a covering called the seed coat usually with some stored Early seed-bearing plants include the ginkgo and conifers. Ginkgo is a genus of highly unusual non-flowering plants with one extant species G The earliest fossil of a flowering plant, Archaefructus liaoningensis, is dated about 125 million years old. Archaefructus is an extinct genus of Herbaceous aquatic Seed plants with two known species ^[2] Several groups of extinct gymnosperms, particularly seed ferns, have been proposed as the ancestors of flowering plants but there is no continuous fossil evidence showing exactly how flowers evolved. Pteridospermatophyta, also called seed ferns, is an extinct Spermatophyte group of the Plantae kingdom. The apparently sudden appearance of relatively modern flowers in the fossil record posed such a problem for the theory of evolution that it was called an "abominable mystery" by Charles Darwin. Charles Robert Darwin (February 12 1809 &ndash April 19 1882 was an English naturalist, who realised and demonstrated that all Species of life Recently discovered angiosperm fossils such as Archaefructus, along with further discoveries of fossil gymnosperms, suggest how angiosperm characteristics may have been acquired in a series of steps.

Recent DNA analysis (molecular systematics)^[3][4] show that Amborella trichopoda, found on the Pacific island of New Caledonia, is the sister group to the rest of the flowering plants, and morphological studies^[5] suggest that it has features which may have been characteristic of the earliest flowering plants. Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known Amborella trichopoda is a rare vesselless understory Shrub or small Tree found only on the island of New Caledonia. For the former North American fur-trading district see New Caledonia (Canada, and for the Scottish colony in Panama see Darien scheme. Cladistics is the hierarchical classification of Species based on evolutionary ancestry

Various flower colors and shapes

A Syrphid fly on a Grape hyacinth

The general assumption is that the function of flowers, from the start, was to involve other animals in the reproduction process. Flies in the Diptera family Syrphidae are commonly known as hoverflies, flower flies, or Syrphid flies. Grape hyacinths are a group of plants in the Genus Muscari of Plants native to Eurasia that produce spikes of blue Flowers resembling Pollen can be scattered without bright colors and obvious shapes, which would therefore be a liability, using the plant's resources, unless they provide some other benefit. One proposed reason for the sudden, fully developed appearance of flowers is that they evolved in an isolated setting like an island, or chain of islands, where the plants bearing them were able to develop a highly specialized relationship with some specific animal (a wasp, for example), the way many island species develop today. This symbiotic relationship, with a hypothetical wasp bearing pollen from one plant to another much the way fig wasps do today, could have eventually resulted in both the plant(s) and their partners developing a high degree of specialization. Fig wasps are Wasps of the family Agaonidae which pollinate Figs or are otherwise associated with figs Island genetics is believed to be a common source of speciation, especially when it comes to radical adaptations which seem to have required inferior transitional forms. Populations with small population size behave differently to larger populations Note that the wasp example is not incidental; bees, apparently evolved specifically for symbiotic plant relationships, are descended from wasps.

Likewise, most fruit used in plant reproduction comes from the enlargement of parts of the flower. The term fruit has different meanings dependent on context and the term is not synonymous in Food preparation and Biology. This fruit is frequently a tool which depends upon animals wishing to eat it, and thus scattering the seeds it contains.

While many such symbiotic relationships remain too fragile to survive competition with mainland animals and spread, flowers proved to be an unusually effective means of production, spreading (whatever their actual origin) to become the dominant form of land plant life. This article is about the biological phenomenon for other uses see Symbiosis (disambiguation The term symbiosis (from the Greek

While there is only hard proof of such flowers existing about 130 million years ago, there is some circumstantial evidence that they did exist up to 250 million years ago. A chemical used by plants to defend their flowers, oleanane, has been detected in fossil plants that old, including gigantopterids^[6], which evolved at that time and bear many of the traits of modern, flowering plants, though they are not known to be flowering plants themselves, because only their stems and prickles have been found preserved in detail; one of the earliest examples of petrification. Oleananes is the name given to chemicals produced by many Flowering plants which have a suppressing effect on some insect pest organisms. Gigantopterids ( Gigantopteridales) is the name given to Fossils of a group of plants existing in the Late Permian, until some 250 million years ago Petrified wood (from the Greek root "petro" meaning "rock" or "stone" literally "wood turned into stone" is a type of Fossil: it

The similarity in leaf and stem structure can be very important, because flowers are genetically just an adaptation of normal leaf and stem components on plants, a combination of genes normally responsible for forming new shoots. In Botany, a leaf is an above-ground Plant organ specialized for Photosynthesis. A stem is one of two main structural axes of a Vascular plant. ^[7] The most primitive flowers are thought to have had a variable number of flower parts, often separate from (but in contact with) each other. The flowers would have tended to grow in a spiral pattern, to be bisexual (in plants, this means both male and female parts on the same flower), and to be dominated by the ovary (female part). Bisexuality refers to sexual behavior with or attraction to people of both sexes or to a bisexual orientation In the Flowering plants an ovary is a part of the female reproductive organ of the flower or Gynoecium. As flowers grew more advanced, some variations developed parts fused together, with a much more specific number and design, and with either specific sexes per flower or plant, or at least "ovary inferior".

Flower evolution continues to the present day; modern flowers have been so profoundly influenced by humans that many of them cannot be pollinated in nature. Many modern, domesticated flowers used to be simple weeds, which only sprouted when the ground was disturbed. Some of them tended to grow with human crops, and the prettiest did not get plucked because of their beauty, developing a dependence upon and special adaptation to human affection. ^[8]

Development

The ABC model of flower development.

The molecular control of floral organ identity determination is fairly well understood. In a simple model, three gene activities interact in a combinatorial manner to determine the developmental identities of the organ primordia within the floral meristem. A meristem is a tissue in all Plants consisting of undifferentiated cells ( meristematic cells) and found in zones of the plant where growth can take place These gene functions are called A, B and C-gene functions. In the first floral whorl only A-genes are expressed, leading to the formation 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 homeotic mutants in Arabidopsis thaliana and snapdragon, Antirrhinum majus. Homeosis is the transformation of one body part into another arising from Mutation in or misexpression of specific developmentally critical Genes It may be caused Arabidopsis ( A-ra-bi-dóp-sis, rockcress) is a genus in the family Brassicaceae. Antirrhinum majus ( Snapdragon) is a species of Antirrhinum native to the Mediterranean region, from Morocco and For example, when there 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 B function but presence of C-function mimics the fourth whorl, leading to the formation of carpels also in the third whorl. See also The ABC Model of Flower Development.

Most genes central in this model belong to the MADS-box genes and are transcription factors that regulate the expression of the genes specific for each floral organ. MADS box is a conserved Sequence motif found in a family of Transcription factors the MADS-box Protein family In the field of Molecular biology, a transcription factor (sometimes called a sequence-specific DNA binding factor is a Protein that binds to specific sequences

Flowering transition

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 will ensure maximal reproductive success. Reproduction is the Biological process by which new individual Organisms are produced To meet these needs a plant is able to interpret important endogenous and environmental cues such as changes in plant hormones levels and seasonable temperature and photoperiodchanges. Plant hormones (also known as phytohormones) are chemicals that regulate plant growth Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature Photoperiodicity is the physiological reaction of organisms to the length of day or night Many perennial and most biennial plants require vernalization to flower. Vernalization (vernalisation - British English) is the acquisition of the competence to flower in the spring by exposure to the prolonged cold of winter The molecular interpretation of these signals through genes such as CONSTANS and FLC ensures that flowering occurs at a time that is favorable for fertilization and the formation of seeds. For soil improvement see Fertilization (soil. A seed (in some plants referred to as a kernel) is a small embryonic Plant enclosed in a covering called the seed coat usually with some stored ^[9] Flower formation is initiated at the ends of stems, and involves a number of different physiological and morphological changes. The first step is the transformation of the vegetative stem primordia into floral primordia. This occurs as biochemical changes take place to change cellular differentiation of leaf, bud and stem tissues into tissue that will grow into the reproductive organs. In Botany, a bud is an undeveloped or embryonic Shoot and normally occurs in the Axil of a Leaf or at the tip of the stem 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 was dependent of some environmental cue. Once the process begins, even if that cue is removed the stem will continue to develop a flower.

Symbolism

Lilies are often used to denote life or resurrection

Flowers inspire decorative motifs

Flowers are common subjects of still lifes, such as this one by Ambrosius Bosschaert the Elder

Chinese Jade ornament with flower design, Jin Dynasty (1115-1234 AD), Shanghai Museum. Ambrosius Bosschaert the Elder ( Antwerp, January 18 1573 &ndash The Hague, 1621 was a Still life painter of the Jade is an Ornamental stone. The term jade is applied to two different rocks that are made up of different Silicate minerals. This is an article for the Jurchen Jin Dynasty (1115–1234 For other Chinese dynasties whose names are also rendered "Jin" in Pinyin, see Jin Dynasty The Shanghai Museum ( Chinese: 上海博物館 is a Museum of ancient Chinese art, situated on the People's Square in the Huangpu District

Flowers are beloved for their various fragrances

Many flowers have important symbolic meanings in Western culture. The musical instrument is spelled Cymbal. A symbol is something --- such as an object, Picture, written word a sound a piece The practice of assigning meanings to flowers is known as floriography. The language of flowers, sometimes called floriography, was a Victorian-era means of Communication in which various Flowers and floral arrangements Some of the more common examples include:

• Red roses are given as a symbol of love, beauty, and passion. A rose is a perennial flowering Shrub or vine of the Genus Rosa, within the family Rosaceae, that contains over 100 species
• Poppies are a symbol of consolation in time of death. A poppy is any of a number of showy Flowers typically withone per stem, belonging to the poppy family. In the UK, New Zealand, Australia and Canada, red poppies are worn to commemorate soldiers who have died in times of war. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located New Zealand is an Island country in the south-western Pacific Ocean comprising two main landmasses (the North Island and the South Island For a topic outline on this subject see List of basic Australia topics. Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page
• Irises/Lily are used in burials as a symbol referring to "resurrection/life". It is also associated with stars (sun) and its petals blooming/shining.
• Daisies are a symbol of innocence. The family Asteraceae or Compositae (known as the aster, daisy, or sunflower family) is the largest family of Flowering

Flowers within art are also representative of the female genitalia, as seen in the works of artists such as Georgia O'Keefe, Imogen Cunningham, Veronica Ruiz de Velasco, and Judy Chicago, and in fact in Asian and western classical art. Georgia Totto O'Keeffe (November 15 1887—March 6 1986 was an American Artist She is associated with the American Southwest where she found artistic inspiration Imogen Cunningham ( April 12 1883 - June 24 1976) was an American Photographer known for her photography of botanicals Veronica Ruiz de Velasco (born in México DF) is a Neo-figurative painter of Mexican origin living in the United States. Judy Chicago (born Judy Cohen on July 20, 1939) is a Feminist artist author and educator Many cultures around the world have a marked tendency to associate flowers with femininity. Female (♀ is the Sex of an Organism, or a part of an organism which produces ova (egg cells

The great variety of delicate and beautiful flowers has inspired the works of numerous poets, especially from the 18th-19th century Romantic era. Romanticism largely began as a reaction against the prevailing Enlightenment ideals of the day Famous examples include William Wordsworth's I Wandered Lonely as a Cloud and William Blake's Ah! Sun-Flower. I WANDERED LONELY AS A CLOUD I William Blake (28 November 1757 – 12 August 1827 was an English poet, painter, and Printmaker.

Because of their varied and colorful appearance, flowers have long been a favorite subject of visual artists as well. Some of the most celebrated paintings from well-known painters are of flowers, such as Van Gogh's sunflowers series or Monet's water lilies. Sunflowers (original title in French Tournesols) are the subject of a series of Still life paintings executed in Oil on canvas by the Claude Monet ( French klod mɔnɛ also known as Oscar-Claude Monet or Claude Oscar Monet (14 November 1840 &ndash 5 December 1926 was a founder Flowers are also dried, freeze dried and pressed in order to create permanent, three-dimensional pieces of flower art.

The Roman goddess of flowers, gardens, and the season of Spring is Flora. In Roman mythology, Flora was a Goddess of flowers and the season of spring. The Greek goddess of spring, flowers and nature is Chloris. This article is about "Chloris" in Greek Mythology For the Genus of tufted grasses in the Poaceae family also known as "Finger grass" and

In Hindu mythology, flowers have a significant status. A Hindu ( Devanagari: हिन्दू is an adherent of the philosophies and scriptures of Hinduism, a set of religious, Philosophical Vishnu, one of the three major gods in the Hindu system, is often depicted standing straight on a lotus flower. For other meanings see Vishnu (disambiguation. Vishnu ( IAST viṣṇu Devanagari विष्णु (honorific A Hindu ( Devanagari: हिन्दू is an adherent of the philosophies and scriptures of Hinduism, a set of religious, Philosophical ^[10] Apart from the association with Vishnu, the Hindu tradition also considers the lotus to have spiritual significance. For other meanings see Vishnu (disambiguation. Vishnu ( IAST viṣṇu Devanagari विष्णु (honorific ^[11] For example, it figures in the Hindu stories of creation. ^[12]

Usage

In modern times, people have sought ways to cultivate, buy, wear, or otherwise be around flowers and blooming plants, partly because of their agreeable appearance and smell. Around the world, people use flowers for a wide range of events and functions that, cumulatively, encompass one's lifetime:

• For new births or Christenings
• As a corsage or boutonniere to be worn at social functions or for holidays
• As tokens of love or esteem
• For wedding flowers for the bridal party, and decorations for the hall
• As brightening decorations within the home
• As a gift of remembrance for bon voyage parties, welcome home parties, and "thinking of you" gifts
• For funeral flowers and expressions of sympathy for the grieving

People therefore grow flowers around their homes, dedicate entire parts of their living space to flower gardens, pick wildflowers, or buy flowers from florists who depend on an entire network of commercial growers and shippers to support their trade. A funeral is a Ceremony marking a person's Death. Funerary customs comprise the complex of Beliefs and practices used by a Culture to remember Sympathy is a social affinity in which one person stands with another person closely understanding his or her feelings A flower garden is a form of Garden usually grown for decorative purposes centering primarily on the kinds of Flowers produced by the plants involved Floristry is the general term used to describe the professional floral trade

Flowers provide less food than other major plants parts (seeds, fruits, roots, stems and leaves) but they provide several important foods and spices. A seed (in some plants referred to as a kernel) is a small embryonic Plant enclosed in a covering called the seed coat usually with some stored The term fruit has different meanings dependent on context and the term is not synonymous in Food preparation and Biology. ROOT is an object-oriented program and library developed by CERN. A stem is one of two main structural axes of a Vascular plant. In Botany, a leaf is an above-ground Plant organ specialized for Photosynthesis. A spice is a dried Seed, Fruit, Root, Bark or vegetative substance used in Nutritionally insignificant quantities as a Food additive Flower vegetables include broccoli, cauliflower and artichoke. Broccoli is a plant of the Cabbage family Brassicaceae (formerly Cruciferae Cauliflower is one of several vegetables in the species Brassica oleracea, in the family Brassicaceae. The Globe Artichoke ( Cynara cardunculus) Globe Artichokes are known to have been cultivated at Naples around the middle of the 9th century and The most expensive spice, saffron, consists of dried stigmas of a crocus. Saffron ( Kurdish/Persian زَعْفَرَان is a Spice derived from the dried Stigma of the Flower of the saffron crocus ( Crocus sativus CROCUS is a Research reactor at École Polytechnique Fédérale de Lausanne in Switzerland, sometimes described as zero power but in fact limited Other flower spices are cloves and capers. This article is about the Spice; for other meanings see Clove (disambiguation. The caper ( Capparis spinosa L is a perennial spiny shrub that bears rounded fleshy leaves and big white to pinkish-white flowers Hops flowers are used to flavor beer. Hops are the female Flower cones of the hop plant ( Humulus lupulus) Beer is the world's oldest and most widely consumed Alcoholic beverage and the third most popular drink overall after water and tea Marigold flowers are fed to chickens to give their egg yolks a golden yellow color, which consumers find more desirable. The chicken ( Gallus gallus, sometimes G gallus domesticus) is a domesticated Fowl which is traditionally believed to have descended from Dandelion flowers are often made into wine. Bee Pollen, pollen collected from bees, is considered a health food by some people. Pollen is a fine to coarse powder consisting of microgametophytes ( pollen grains) which produce the male Gametes (sperm cells of Honey consists of bee-processed flower nectar and is often named for the type of flower, e. Honey is a sweet and Viscous fluid produced by Honey bees (and some other species and derived from the nectar of Flowers According to the g. orange blossom honey, clover honey and tupelo honey. An orange —specifically the sweet orange —is the Citrus fruit Citrus sinensis ( syn Alsike redirects here Alsike Sweden is also a town in the Knivsta Municipality, Sweden. The tupelos, or pepperidge tree, genus Nyssa, are a small Genus of about 9 to 11 species of Trees with alternate simple leaves

Hundreds of fresh flowers are edible but few are widely marketed as food. They are often used to add color and flavor to salads. Squash flowers are dipped in breadcrumbs and fried. Squashes generally refer to four species of the genus Cucurbita native to the Mexico and Central America, also called marrows depending Edible flowers include nasturtium, chrysanthemum, carnation, cattail, honeysuckle, chicory, cornflower, Canna, and sunflower. Chrysanthemums, often called 'mums' are a genus ( Chrysanthemum) of about 30 species of perennial Flowering plants in the family Asteraceae Typha is a Genus of about eleven Species of Monocotyledonous flowering plants in the Monogeneric family Typhaceae Honeysuckles ( Lonicera; syn Caprifolium Mill) are arching Shrubs or twining Vines in the family Caprifoliaceae Common Chicory ( Cichorium intybus) is a bushy perennial Herb with blue lavender or occasionally white Flowers It grows Centaurea cyanus ( Cornflower, Bachelor's button, Basket flower, Bluebottle, Boutonniere flower, Hurtsickle) is a small Canna (or Canna lily, although not a true Lily) is a Genus of approximately twenty Species of Flowering plants The sunflower ( Helianthus annuus) is an Annual plant in the family Asteraceae and native to the Americas, with a large flowering Some edible flowers are sometimes candied such as daisy and rose (you may also come across a candied pansy). A rose is a perennial flowering Shrub or vine of the Genus Rosa, within the family Rosaceae, that contains over 100 species The pansy or pansy violet s are a large group of plants cultivated as garden Flowers Pansies are derived from Viola tricolor and can include

Flowers can also be made into herbal teas. An herbal tea, tisane, or ptisan is an Herbal Infusion made from anything other than the leaves of the Tea bush ( Camellia Dried flowers such as chrysanthemum, rose, jasmine, camomile are infused into tea both for their fragrance and medical properties. Sometimes, they are also mixed with tea leaves for the added fragrance. Camellia sinensis is the tea plant, the Plant Species whose leaves and leaf buds are used to produce Tea.

See also

• Plants
• List of garden plants
• Plant sexuality
• Garden
• Gardening
• Sowing
• Evolution of plants
• Plant evolutionary developmental biology

References

• Eames, A. J. (1961) Morphology of the Angiosperms McGraw-Hill Book Co. , New York.
• Esau, Katherine (1965) Plant Anatomy (2nd ed. ) John Wiley & Sons, New York.

See our image gallery on this topic at: flowers

External links

• Native Plant Information Network
• Garden Guide UK - Information on Flowers and Colours