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Encyclopedia > Flower
Look up flower in
Wiktionary, the free dictionary.
Rudbeckia fulgida inflorescences
Rudbeckia fulgida inflorescences
Etlingera corneri—Siam Rose
Etlingera corneri—Siam Rose

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). The flower's structure contains the plant's reproductive organs, and its function is to produce seeds. After fertilization, portions of the flower develop into a fruit containing 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 is called the inflorescence. Flower can mean several things: Flower, a structure found in plants Flower, in ancient chemistry, is the powdery form of any substance, especially as the result of condensation after sublimation. ... Wikipedia does not have an article with this exact name. ... Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Web-based project to create a free content dictionary, available in over 150 languages. ... Image File history File links Download high-resolution version (1500x1339, 479 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Flower ... Image File history File links Download high-resolution version (1500x1339, 479 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Flower ... Type Species Phalaenopsis amabilis Blume, (1825) Species See text. ... Image File history File links Size of this preview: 800 × 541 pixel Image in higher resolution (1658 × 1122 pixel, file size: 1. ... Image File history File links Size of this preview: 800 × 541 pixel Image in higher resolution (1658 × 1122 pixel, file size: 1. ... Binomial name Rudbeckia fulgida L. Rudbeckia fulgida, commonly known as Black-eyed Susan or Orange coneflower, is a perennial plant native to eastern North America. ... Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (3072 × 2304 pixel, file size: 5. ... Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (3072 × 2304 pixel, file size: 5. ... For other uses, see Reproduction (disambiguation) Reproduction is the biological process by which new individual organisms are produced. ... Classes Magnoliopsida - Dicots Liliopsida - Monocots The flowering plants or angiosperms are the most widespread group of land plants. ... A ripe red jalapeño cut open to show the seeds For other uses, see Seed (disambiguation). ... Categories: Biology stubs ... For other uses, see Fruit (disambiguation). ... Red clover inflorescence (spike) An inflorescence is a group or cluster of flowers on a branch of a plant. ...


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.

Contents

Function

The biological function of a flower is to mediate the union of male and female gametes in order to produce seeds. The process begins with pollination, is followed by fertilization, and continues with the formation and dispersal of the seed. Gametes (in Greek: γαμέτες) —also known as sex cells, germ cells, or spores—are the specialized cells that come together during fertilization (conception) in organisms that reproduce sexually. ... A ripe red jalapeño cut open to show the seeds For other uses, see Seed (disambiguation). ... Carpenter bee with pollen collected from Night-blooming cereus Pollination is an important step in the reproduction of seed plants: the transfer of pollen grains (male gametes) to the plant carpel, the structure that contains the ovule (female gamete). ... Categories: Biology stubs ... This article does not cite any references or sources. ...


Morphology

Flowering plants are heterosporangiate, producing two types of reproductive spores. 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. This article or section is in need of attention from an expert on the subject. ... SEM image of pollen grains from a variety of common plants: sunflower (Helianthus annuus), morning glory (Ipomoea purpurea), prairie hollyhock (Sidalcea malviflora), oriental lily (Lilium auratum), evening primrose (Oenothera fruticosa), and castor bean (Ricinus communis). ... This article or section does not adequately cite its references or sources. ... This article is about the biological unit. ...


A flower is regarded as a modified stem with shortened internodes and bearing, at its nodes, structures that may be highly modified leaves.[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). 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. If the peduncle ends with groups of flowers, each stem that holds a flower is called a pedicel. 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: Stem showing internode and nodes plus leaf petiole and new stem rising from node. ... A node is the place on a stem where a lateral meristem develops as either a lateral bud or a secondary shoot, often subtended by a leaf. ... Look up foliage in Wiktionary, the free dictionary. ... Tunica-Corpus model of the apical meristem. ... The term peduncle has several meanings: In botany, a Peduncle (botany) is a flower stalk, or stem. ... In anatomy, the pedicle (also spelled pedicel) is the segment between the transverse process and the vertebral body. ... Look up whorl in Wiktionary, the free dictionary. ...

Morphology of Oxalis acetosella flower. 1: petal, 2: sepal, 3: anther, 4: stigma, 5: ovary, 6: ovary, 7: ovule.
Morphology of Oxalis acetosella flower. 1: petal, 2: sepal, 3: anther, 4: stigma, 5: ovary, 6: ovary, 7: ovule.
  • Calyx: the outer whorl of sepals; typically these are green, but are petal-like in some species.
  • Corolla: the whorl of petals, which are usually thin, soft and colored to attract insects that help the process of pollination.
  • 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. Pollen contains the male gametes.
  • Gynoecium (from Greek gynaikos oikia: woman's house): one or more pistils. The female reproductive organ is the carpel: this contains an ovary with ovules (which contain female gametes). 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.

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. The number of carpels in a compound pistil may be only two, or otherwise not related to the above generalization for monocots and dicots. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Flower of the Primrose Willowherb (Ludwigia octovalvis) showing petals and sepals A sepal is one member or part of the calyx of a flower. ... Flower of the Primrose Willowherb (Ludwigia octovalvis) showing petals and sepals A sepal is one member or part of the calyx of a flower. ... Corolla can be: A Latin-language term for crown The Toyota Corolla, a model of automobile manufactured by Toyota The corolla is one whorl of the perianth of a flower and composed of petals The town of Corolla, North Carolina This is a disambiguation page, a list of pages that... It has been suggested that Corolla be merged into this article or section. ... Carpenter bee with pollen collected from Night-blooming cereus Pollination is an important step in the reproduction of seed plants: the transfer of pollen grains (male gametes) to the plant carpel, the structure that contains the ovule (female gamete). ... An androecium is a male part of a flower in a flowering plant. ... Stamens of the Amaryllis with prominent anthers carrying pollen Insects, while collecting nectar, unintentionally transfer pollen from one flower to another, bringing about pollination The stamen (from Latin stamen meaning thread of the warp) is the male organ of a flower. ... Filaments surrounding a solar flare, caused by the interaction of the plasma in the Suns atmopshere with its magnetic field. ... Flower of the spider tree (Crateva religiosa) with its numerous conspicuous stamens The stamen is the male organ of a flower. ... SEM image of pollen grains from a variety of common plants: sunflower (Helianthus annuus), morning glory (Ipomoea purpurea), prairie hollyhock (Sidalcea malviflora), oriental lily (Lilium auratum), evening primrose (Oenothera fruticosa), and castor bean (Ricinus communis). ... A gamete (from Ancient Greek γαμετης; translated gamete = wife, gametes = husband) is a cell that fuses with another gamete during fertilization (conception) in organisms that reproduce sexually. ... A gynoecium(gyne: woman) is the female reproductive part of a flower, the male part of a flower is called androecium. ... The Pistil is the part of the flower made up of one or more carpels. ... Amaryllis style and stigmas A carpel is the outer, often visible part of the female reproductive organ of a flower; the basic unit of the gynoecium. ... Look up stigma on Wiktionary, the free dictionary. ... Pollen may refer to the microspores of either angiosperms (flowering plants) or gymnosperms (conifers and cycads). ... Orders See text. ... Hemerocallis flower, with three flower parts in each whorl Wheat, an economically important monocot The monocotyledons or Monocots are a group of flowering plants, (angiosperms) dominating great parts of the earth. ...

This Crateva religiosa flower is perfect: it has both stamens (outer ring) and a pistil (center).
This Crateva religiosa flower is perfect: it has both stamens (outer ring) and a pistil (center).

In the majority of species individual flowers have both pistils and stamens as described above. These flowers are described by botanists as being perfect, bisexual, or hermaphrodite. 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. However, where unisexual male and female flowers appear on the same plant, the species is considered monoecious. Download high resolution version (800x865, 327 KB)Photograph of a flower of Crateva religiosa (Capparaceae) by Eric Guinther and released under the GNU Free Documentation License. ... Download high resolution version (800x865, 327 KB)Photograph of a flower of Crateva religiosa (Capparaceae) by Eric Guinther and released under the GNU Free Documentation License. ... Binomial name Crateva religiosa Forst. ... The Pistil is the part of the flower made up of one or more carpels. ... The 1st-century BC sculpture The Reclining Hermaphrodite, in the Museo Nazionale Romano, Palazzo Massimo Alle Terme in Rome A hermaphrodite is an organism that possesses both male and female sex organs during its life. ... Close-up of an Echinopsis spachiana flower, showing both carpels and stamen, making it a complete flower. ... Close-up of an Echinopsis spachiana flower, showing both carpels and stamen, making it a complete flower. ...

Some flowers have modified structures. Here the style is extended into an umbrella shape which catches pollen and aids pollination. (Sarracenia).
Some flowers have modified structures. Here the style is extended into an umbrella shape which catches pollen and aids pollination. (Sarracenia).

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. 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). 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. Image File history File links Sarracenia_flower_notitles. ... Image File history File links Sarracenia_flower_notitles. ... Sarracenia range (all species) Species See text. ... Red clover inflorescence (spike) An inflorescence is a group or cluster of flowers on a branch of a plant. ... Look up Daisy in Wiktionary, the free dictionary. ... For other uses, see Sunflower (disambiguation). ... Example of a flower head. ...


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. The following representations are used: The hierarchy of scientific classification In biological classification, family (Latin: familia, plural familiae) is a rank, or a taxon in that rank. ...


Ca = calyx (sepal whorl; e.g. Ca5 = 5 sepals)
Co = corolla (petal whorl; e.g., Co3(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:

Ca5Co5A10 - ∞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
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 by the joining of pollen of one plant with the ovules of another (or in some cases its own ovules) in order to form seed which grows into the next generation of plants. Sexual reproduction produces genetically unique offspring, allowing for adaptation to occur. As such, each flower has a specific design which best encourages the transfer of this pollen. Many flowers are dependent upon the wind to move pollen between flowers of the same species. Others rely on animals (especially insects) to accomplish this feat. Even large animals such as birds, bats, and pygmy possums can be employed. The period of time during which this process can take place (the flower is fully expanded and functional) is called anthesis. Image File history File links Bees_Collecting_Pollen_cropped. ... Image File history File links Bees_Collecting_Pollen_cropped. ... Carpenter bee with pollen collected from Night-blooming cereus Pollination is an important step in the reproduction of seed plants: the transfer of pollen grains (male gametes) to the plant carpel, the structure that contains the ovule (female gamete). ... For other uses, see Reproduction (disambiguation) Reproduction is the biological process by which new individual organisms are produced. ... For other uses, see Adaptation (disambiguation). ... Orders Subclass Apterygota Archaeognatha (bristletails) Thysanura (silverfish) Subclass Pterygota Infraclass Paleoptera (Probably paraphyletic) Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Superorder Exopterygota Grylloblattodea (ice-crawlers) Mantophasmatodea (gladiators) Plecoptera (stoneflies) Embioptera (webspinners) Zoraptera (angel insects) Dermaptera (earwigs) Orthoptera (grasshoppers, etc) Phasmatodea (stick insects) Blattodea (cockroaches) Isoptera (termites) Mantodea (mantids) Psocoptera... Genera Burramys Cercartetus The pygmy possums are the small possums of the family Burramyidae. ...


Attraction methods

Bee orchid mimics a female bee in order to attract a male bee pollinator
Bee orchid mimics a female bee in order to attract a male bee pollinator

Many flowers in nature have evolved to attract animals to pollinate the flower, the movements of the pollinating agent contributing to the opportunity for genetic recombination within a dispersed plant population. Flowers that are insect-pollinated are called entomophilous (literally "insect-loving"). Flowers commonly have glands called nectaries on their various parts that attract these animals. Birds and bees are common pollinators: both having color vision, thus opting for "colorful" flowers. Some flowers have patterns, called nectar guides, that show pollinators where to look for nectar; they may be visible to us or only under ultraviolet light, which is visible to bees and some other insects. Flowers also attract pollinators by scent. Many of their scents are pleasant to our sense of smell, but not all. Some plants, such as Rafflesia, the titan arum, and the North American pawpaw (Asimina triloba), are pollinated by flies, so they produce a scent imitating rotting meat. Flowers pollinated by night visitors such as bats or moths are especially likely to concentrate on scent—which can attract pollinators in the dark—rather than color: most such flowers are white. Image File history File links Download high resolution version (595x745, 121 KB) Description: Ophrys apifera, flower Picture taken by BerndH Date: 12. ... Image File history File links Download high resolution version (595x745, 121 KB) Description: Ophrys apifera, flower Picture taken by BerndH Date: 12. ... Binomial name Ophrys apifera The Bee Orchid (Ophrys apifera Hudson) is a rare and protected perennial, growing on semi-dry turf, on limestone, calcareous dunes or in open areas in woodland. ... For other uses, see Bird (disambiguation). ... For other uses, see Western honey bee and Bee (disambiguation). ... A pollinator is the agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization or syngamy of the female gamete in the ovule of the flower by the male gamete from the pollen grain. ... Nectar guides are patterns seen in some flowers, such as sunflowers, when viewed under ultraviolet light. ... For other uses, see Ultraviolet (disambiguation). ... “Aroma” redirects here. ... Species See text. ... Binomial name Amorphophallus titanum (Becc. ... Species See text Pawpaw (Asimina) is a genus of eight or nine species of small trees with large leaves and fruit, native to eastern North America. ... For other uses, see Fly (disambiguation) and Flies (disambiguation). ... Stinking flowers or Carrion flowers are flowers that smell like rotting flesh. ...


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 range (all species) Species See text. ... Genera See Taxonomy of the orchid family. ... Self-pollination is the activity that arises when a flower has both stamen and pistils. ...


Anemophilous: flowers use the wind to move pollen from one flower to the next, examples include the grasses, Birch trees, Ragweed and Maples. 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. Honeybees and bumblebees actively gather anemophilous corn (maize) pollen, though it is of little value to them. Subfamilies There are 7 subfamilies: Subfamily Arundinoideae Subfamily Bambusoideae Subfamily Centothecoideae Subfamily Chloridoideae Subfamily Panicoideae Subfamily Pooideae Subfamily Stipoideae The true grasses are monocotyledonous plants (Class Liliopsida) in the Family Poaceae, also known as Gramineae. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Orders Subclass Apterygota Archaeognatha (bristletails) Thysanura (silverfish) Subclass Pterygota Infraclass Paleoptera (Probably paraphyletic) Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Superorder Exopterygota Grylloblattodea (ice-crawlers) Mantophasmatodea (gladiators) Plecoptera (stoneflies) Embioptera (webspinners) Zoraptera (angel insects) Dermaptera (earwigs) Orthoptera (grasshoppers, etc) Phasmatodea (stick insects) Blattodea (cockroaches) Isoptera (termites) Mantodea (mantids) Psocoptera... This article is about the maize plant. ...


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. Bumblebees and the flowers they pollinate co-evolve so that the flower is dependent on the bee and the bee is dependent on the flower for survival In Biology, Co-evolution is the mutual evolutionary influence between two species that become dependent on each other. ...


This close relationship compounds the negative effects of extinction. 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. For other uses, see Extinction (disambiguation). ... The Siberian Tiger is a subspecies of tiger that are critically endangered. ... Pollinator decline is based on observations made at the end of the twentieth century of the reduction in abundance of pollinators in many ecosystems worldwide. ...


Fertilization and dispersal

Main article: biological dispersal
In this picture you can clearly see the stamens of the flower
In this picture you can clearly see the stamens of the flower

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). This article does not cite any references or sources. ... Image File history File linksMetadata Download high-resolution version (3008x2000, 3018 KB) I, the creator of this work, hereby release it into the public domain. ... Image File history File linksMetadata Download high-resolution version (3008x2000, 3018 KB) I, the creator of this work, hereby release it into the public domain. ... For other uses, see Dandelion (disambiguation). ... Close-up of an Echinopsis spachiana flower, showing both carpels and stamen, making it a complete flower. ...


Evolution

Flowers in Kamakura, Japan

While land plants have existed for about 425 million years, the first ones reproduced by a simple adaptation of their aquatic counterparts: spores. In the sea, plants -- and some animals -- can simply scatter out little living copies of themselves to float away and grow elsewhere. This is how early plants, such as the modern fern, are thought to have reproduced. But plants soon began 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...but not, yet, flowers. Early seed-bearing plants include the ginkgo, conifers (like pines and fir trees). The earliest fossil of a flowering plant, Archaefructus liaoningensis, is dated about 125 million years old.[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. 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. 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. Image File history File links Metadata Size of this preview: 799 × 600 pixelsFull resolution (1126 × 845 pixel, file size: 236 KB, MIME type: image/jpeg) A group of flowers in Kamakura, Japan I, the copyright holder of this work, hereby grant the permission to copy, distribute and/or modify this... Image File history File links Metadata Size of this preview: 799 × 600 pixelsFull resolution (1126 × 845 pixel, file size: 236 KB, MIME type: image/jpeg) A group of flowers in Kamakura, Japan I, the copyright holder of this work, hereby grant the permission to copy, distribute and/or modify this... Kamakura can refer to: Kamakura, Kanagawa, a city in Kanagawa Prefecture, Japan The Kamakura Shogunate The Kamakura period in the History of Japan The Kamakura family name in Japan Kamakura Great Buddha, the Great Buddha of Kamakura Kamakura, a fictional character from the G.I. Joe series Category: ... Close-up of an Echinopsis spachiana flower, showing both carpels and stamen, making it a complete flower. ... This article or section is in need of attention from an expert on the subject. ... A ripe red jalapeño cut open to show the seeds For other uses, see Seed (disambiguation). ... Species G. biloba L. The Ginkgo (Ginkgo biloba; 銀杏 in Chinese), frequently misspelled as Gingko, and also known as the Maidenhair Tree, is a unique tree with no close living relatives. ... Orders & Families Cordaitales † Pinales   Pinaceae - Pine family   Araucariaceae - Araucaria family   Podocarpaceae - Yellow-wood family   Sciadopityaceae - Umbrella-pine family   Cupressaceae - Cypress family   Cephalotaxaceae - Plum-yew family   Taxaceae - Yew family Vojnovskyales † Voltziales † The conifers, division Pinophyta, are one of 13 or 14 division level taxa within the Kingdom Plantae. ... FIR may stand for: finite impulse response (a property of some digital filters) far infrared, i. ... Species Archaefructus liaoningensis Archaefructus sinensis Archaefructus is an extinct genus of herbaceous aquatic flowering plants. ... Pteridospermatophyta, also called seed ferns, is an extinct gymnosperm division of the Plantae kingdom. ... For other people of the same surname, and places and things named after Charles Darwin, see Darwin. ...


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. The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... It has been suggested that molecular phylogeny be merged into this article or section. ... Binomial name Amborella trichopoda Baill. ... This cladogram shows the relationship among various insect groups. ...

Various flower colors and shapes

The general assumption is that the function of flowers, from the start, was to involve other animals in the reproduction process. 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. 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. Note that the wasp example is not incidental; bees, apparently evolved specifically for symbiotic plant relationships, are descended from wasps. Image File history File links Flores. ... Image File history File links Flores. ... Image File history File linksMetadata Size of this preview: 516 × 599 pixel Image in higher resolution (1057 × 1227 pixel, file size: 1. ... Image File history File linksMetadata Size of this preview: 516 × 599 pixel Image in higher resolution (1057 × 1227 pixel, file size: 1. ... Genera many genera about 5,000 species The flower flies or hoverflies are a family of flies (Diptera), scientifically termed Syrphidae. ... Species about 40, including: (=) (= ) Grape hyacinths are a genus (Muscari) of plants native to Eurasia that produce spikes of blue flowers resembling bunches of grapes. ... Subfamilies Agaoninae Epichrysomallinae Otitesellinae Sycoecinae Sycophaginae Sycoryctinae Fig wasps are wasps of the family Agaonidae which pollinate figs or are otherwise associated with figs. ... Species with a small population size are subject to a higher chance of extinction because they are more vulnerable to genetic drift, resulting in stochastic variation in their gene pool, their demography and their environment. ...


Likewise, most fruit used in plant reproduction comes from the enlargement of parts of the flower. This fruit is frequently a tool which depends upon animals wishing to eat it, and thus scattering the seeds it contains. For other uses, see Fruit (disambiguation). ...


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. Common Clownfish (Amphiprion ocellaris) in their magnificent sea anemone (Heteractis magnifica) home. ...


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. Oleanane is the name given to a chemical produced by many flowering plants, which has a suppressing effect on some insect threats. ... Gigantopterid is the name given to fossils of a group of plants existing 250 million years ago, which bore many of the traits of flowering plants, quite possibly having been a close relative, but are not proven to have flowered, themselves. ... Petrified log at the Petrified Forest National Park A petrified tree from California Petrified wood is a type of fossil: it consists of fossil wood where all the organic materials have been replaced with minerals (most often a silicate, such as quartz), while retaining the original structure of the wood. ...


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.[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). 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". Look up foliage in Wiktionary, the free dictionary. ... Stem showing internode and nodes plus leaf petiole and new stem rising from node. ... In human sexuality, bisexuality describes a man or woman having a sexual orientation to persons of either or both sexes (a man or woman who sexually likes both sexes; people who are sexually and/or romantically attracted to both males and females). ... Longitudinal section of female flower of squash showing ovary, ovules, pistil, and petals In the flowering plants, an ovary is a part of the female reproductive organ of the flower or gynoecium. ...


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 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. 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. 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. Tunica-Corpus model of the apical meristem. ... Homeosis is the transformation of one body part into another, arising from mutation in or misexpression of specific developmentally critical genes. ... Binomial name Antirrhinum majus Antirrhinum majus, the Snapdragon, is an herbaceous perennial plant. ... A diagram of the ABC model. ...


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 element found in a family of transcription factor encoding genes, the MADS-box gene family. ... In the context of genetics, a transcription factor is a regulatory protein that initiates the transcription of certain genes upon binding with DNA. The binding of a transcription factor to a specific DNA sequence can result in either an increased rate of transcription of the gene, known as activated transcription...


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. 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. Many perennial and most biennial plants require vernalization to flower. 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.[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. 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. In telecommunication, a transition is the change from one signal state to another signal state. ... Reproduction is the creation of one thing as a copy of, product of, or replacement for a similar thing, e. ... Plant hormones (or plant growth regulators, or PGRs) are internally secreted chemicals in plants that are used for regulating their growth. ... For other uses, see Temperature (disambiguation). ... Photoperiodism is the physiological reaction of organisms to the length of day or night. ... This article contains information that has not been verified and thus might not be reliable. ... Categories: Biology stubs ... This writeup is about biological seeds; for other meanings see Seed (disambiguation). ... Flower buds have not yet bloomed into a full-size flower. ...


See also

u fuck in ua ... Close-up of an Echinopsis spachiana flower, showing both carpels and stamen, making it a complete flower. ... This article needs additional references or sources for verification. ... Sowing is the process of planting seeds. ...

References

  1. ^ Eames, A. J. (1961) Morphology of the Angiosperms McGraw-Hill Book Co., New York.
  2. ^ Flowers Modern & Ancient
  3. ^ First Flower
  4. ^ Amborella not a "basal angiosperm"? Not so fast
  5. ^ South Pacific plant may be missing link in evolution of flowering plants
  6. ^ Oily Fossils Provide Clues To The Evolution Of Flowers
  7. ^ Age-Old Question On Evolution Of Flowers Answered
  8. ^ Human Affection Altered Evolution of Flowers
  9. ^ Ausin et al (2005), Environmental regulation of flowering. Int J Dev Biol. 2005;49(5-6):689-705
  • 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.

External links

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Image File history File links Commons-logo. ... Wikipedia does not have an article with this exact name. ... Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Web-based project to create a free content dictionary, available in over 150 languages. ...


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