Flower

A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Magnoliophyta, also called angiosperms). The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs. Flowers may facilitate outcrossing (fusion of sperm and eggs from different individuals in a population) or allow selfing (fusion of sperm and egg from the same flower). Some flowers produce diaspores without fertilization (parthenocarpy). Flowers contain sporangia and are the site where gametophytes develop. Many flowers have evolved to be attractive to animals, so as to cause them to be vectors for the transfer of pollen. After fertilization, the ovary of the flower develops into fruit containing seeds.

In addition to facilitating the reproduction of flowering plants, flowers have long been admired and used by humans to bring beauty to their environment, and also as objects of romance, ritual, religion, medicine and as a source of food.

Flower poster 2
A poster with flowers or clusters of flowers produced by twelve species of flowering plants from different families.
Bloemenpanorama Maurice van Bruggen
Flowers in the Netherlands.

Morphology

Ranunculus glaberrimus labelled
Main parts of a mature flower (Ranunculus glaberrimus).
Mature flower diagram
Diagram of flower parts.

Floral parts

The essential parts of a flower can be considered in two parts: the vegetative part, consisting of petals and associated structures in the perianth, and the reproductive or sexual parts. A stereotypical flower consists of four kinds of structures attached to the tip of a short stalk. Each of these kinds of parts is arranged in a whorl on the receptacle. The four main whorls (starting from the base of the flower or lowest node and working upwards) are as follows:

Perianth

Collectively the calyx and corolla form the perianth (see diagram).

  • Calyx: the outermost whorl consisting of units called sepals; these are typically green and enclose the rest of the flower in the bud stage, however, they can be absent or prominent and petal-like in some species.
  • Corolla: the next whorl toward the apex, composed of units called petals, which are typically thin, soft and colored to attract animals that help the process of pollination.

Reproductive

Lillium Stamens
Reproductive parts of Easter Lily (Lilium longiflorum). 1. Stigma, 2. Style, 3. Stamens, 4. Filament, 5. Petal
  • Androecium (from Greek andros oikia: man's house): the next whorl (sometimes multiplied into several whorls), consisting of units called stamens. Stamens consist of two parts: a stalk called a filament, topped by an anther where pollen is produced by meiosis and eventually dispersed.
  • Gynoecium (from Greek gynaikos oikia: woman's house): the innermost whorl of a flower, consisting of one or more units called carpels. The carpel or multiple fused carpels form a hollow structure called an ovary, which produces ovules internally. Ovules are megasporangia and they in turn produce megaspores by meiosis which develop into female gametophytes. These give rise to egg cells. The gynoecium of a flower is also described using an alternative terminology wherein the structure one sees in the innermost whorl (consisting of an ovary, style and stigma) is called a pistil. A pistil may consist of a single carpel or a number of carpels fused together. 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. The relationship to the gynoecium on the receptacle is described as hypogynous (beneath a superior ovary), perigynous (surrounding a superior ovary), or epigynous (above inferior ovary).

Structure

Although the arrangement described above is considered "typical", plant species show a wide variation in floral structure.[1] These modifications have significance in the evolution of flowering plants and are used extensively by botanists to establish relationships among plant species.

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 and/or look like what is typically another part. In some families, like Ranunculaceae, the petals are greatly reduced and in many species the sepals are colorful and petal-like. Other flowers have modified stamens that are petal-like; the double flowers of Peonies and Roses are mostly petaloid stamens.[2] Flowers show great variation and plant scientists describe this variation in a systematic way to identify and distinguish species.

Specific terminology is used to describe flowers and their parts. Many flower parts are fused together; fused parts originating from the same whorl are connate, while fused parts originating from different whorls are adnate; parts that are not fused are free. When petals are fused into a tube or ring that falls away as a single unit, they are sympetalous (also called gamopetalous). Connate petals may have distinctive regions: the cylindrical base is the tube, the expanding region is the throat and the flaring outer region is the limb. A sympetalous flower, with bilateral symmetry with an upper and lower lip, is bilabiate. Flowers with connate petals or sepals may have various shaped corolla or calyx, including campanulate, funnelform, tubular, urceolate, salverform or rotate.

Referring to "fusion," as it is commonly done, appears questionable because at least some of the processes involved may be non-fusion processes. For example, the addition of intercalary growth at or below the base of the primordia of floral appendages such as sepals, petals, stamens and carpels may lead to a common base that is not the result of fusion.[3][4][5]

Peloric Streptocarpus flower
Left: A normal zygomorphic Streptocarpus flower. Right: An aberrant peloric Streptocarpus flower. Both of these flowers appeared on the Streptocarpus hybrid 'Anderson's Crows' Wings'.

Many flowers have a symmetry. When the perianth is bisected through the central axis from any point and symmetrical halves are produced, the flower is said to be actinomorphic or regular, e.g. rose or trillium. 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, e.g. snapdragon or most orchids.

Flowers may be directly attached to the plant at their base (sessile—the supporting stalk or stem is highly reduced or absent). The stem or stalk subtending a flower 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.

Inflorescence

White and yellow flower
The familiar calla lily is not a single flower. It is actually an inflorescence of tiny flowers pressed together on a central stalk that is surrounded by a large petal-like bract.

In those species that have more than one flower on an axis, the collective cluster of flowers is termed an inflorescence. Some inflorescences are composed of many small flowers arranged in a formation that resembles a single flower. The 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.

Floral diagrams and floral formulae

A floral formula 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 the existing model to broaden the descriptive capability of the formula.[6] The format of floral formulae differs in different parts of the world, yet they convey the same information.[7][8][9][10]

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 the relative positions of the various organs, including the presence of fusion and symmetry, as well as structural details.[7]

Development

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.[11] 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.[5][1] Taking into account 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).[12][13]

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 is favorable for fertilization and the formation of seeds, hence ensuring maximal reproductive success. To meet these needs a plant is able to interpret important endogenous and environmental cues such as changes in levels of plant hormones and seasonable temperature and photoperiod changes.[14] 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 is produced in the leaves in reproductively favorable conditions and acts in buds and growing tips to induce a number of different physiological and morphological changes.[15]

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 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.[16] Once the process begins, even if that cue is removed the stem will continue to develop a flower.

Yvonne Aitken has shown that flowering transition depends on a number of factors, and that plants flowering earliest under given conditions had the least dependence on climate whereas later-flowering varieties reacted strongly to the climate setup.

Organ development

ABC flower development
The ABC model of flower development

The molecular control of floral organ identity determination appears to be fairly well understood in some species. 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 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.

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.

Floral function

Crateva religiosa
A "perfect flower", this Crateva religiosa flower has both stamens (outer ring) and a pistil (center).

The principal purpose of a flower is the reproduction of the individual and the species. All flowering plants are heterosporous, producing two types of spores. Microspores are produced by meiosis inside anthers while megaspores are produced inside ovules, inside an ovary. In fact, 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, the gametophytes also develop inside the spores (are endosporic).

In the majority of species, individual flowers have both functional carpels and stamens. Botanists describe these flowers as being perfect or bisexual and the species as hermaphroditic. Some flowers lack one or the other reproductive organ and called imperfect or unisexual. If unisex flowers are found on the same individual plant but in different locations, the species is said to be monoecious. If each type of unisex flower is found only on separate individuals, the plant is dioecious.

Flower specialization and pollination

Flowering plants usually face selective pressure to optimize the transfer of their pollen, and this is typically reflected in the morphology of the flowers and the behaviour of the plants. Pollen may be transferred between plants via a number of 'vectors'. Some plants make use of abiotic vectors — namely wind (anemophily) or, much less commonly, water (hydrophily). Others use biotic vectors including insects (entomophily), birds (ornithophily), bats (chiropterophily) or other animals. Some plants make use of multiple vectors, but many are highly specialised.

Cleistogamous flowers are self-pollinated, after which they may or may not open. Many Viola and some Salvia species are known to have these types of flowers.

The flowers of plants that make use of biotic pollen vectors commonly have glands called nectaries that act as an incentive for animals to visit the flower. Some flowers have patterns, called nectar guides, that show pollinators where to look for nectar. 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). 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 grasses, birch trees, ragweed and maples. 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 animal-pollinated 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 animals.

Pollination

Bees Collecting Pollen cropped
Grains of pollen sticking to this bee will be transferred to the next flower it visits

The primary purpose of a flower is reproduction. Since the flowers are the reproductive organs of 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. The joining of the sperm to the ovules is called fertilization. Normally pollen is moved from one plant to another, but many plants are able to self pollinate. The fertilized ovules produce seeds that are the next generation. Sexual reproduction produces genetically unique offspring, allowing for adaptation. 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 for pollination, including: wind and animals, and especially insects. 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. The study of pollination by insects is called anthecology.

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 flowers 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.

Grassflower
Grass flower with vestigial perianth or lodicules

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 grow large blossoms. 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.

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. 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. 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.

Attraction methods

Ophrys apifera flower1
A Bee orchid has evolved over many generations to better mimic a female bee to attract male bees as pollinators.

Plants cannot move from one location to another, thus many flowers have evolved to attract animals to transfer pollen between individuals in dispersed populations. Flowers that are insect-pollinated are called entomophilous; literally "insect-loving" in Greek. They can be highly modified along with the pollinating insects by co-evolution. Flowers commonly have glands called nectaries on various parts that attract animals looking for nutritious 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 is visible to bees and some other insects. 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). Flowers pollinated by night visitors, including bats and moths, are likely to concentrate on scent to attract pollinators and most such flowers are white.

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.

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.

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.

Pollen allergy

There is much confusion about the role of flowers in allergies. For example, the showy and entomophilous goldenrod (Solidago) is frequently blamed for respiratory allergies, of which it is innocent, since its pollen cannot be airborne. The types of pollen that most commonly cause allergic reactions are produced by the plain-looking plants (trees, grasses, and weeds) that do not have showy flowers. These plants make small, light, dry pollen grains that are custom-made for wind transport.

The type of allergens in the pollen is the main factor that determines whether the pollen is likely to cause hay fever. For example, pine tree pollen is produced in large amounts by a common tree, which would make it a good candidate for causing allergy. It is, however, a relatively rare cause of allergy because the types of allergens in pine pollen appear to make it less allergenic. Instead the allergen is usually the pollen of the contemporary bloom of anemophilous ragweed (Ambrosia), which can drift for many miles. Scientists have collected samples of ragweed pollen 400 miles out at sea and 2 miles high in the air.[17] A single ragweed plant can generate a million grains of pollen per day.[18]

Among North American plants, weeds are the most prolific producers of allergenic pollen.[19] Ragweed is the major culprit, but other important sources are sagebrush, redroot pigweed, lamb's quarters, Russian thistle (tumbleweed), and English plantain.

It is common to hear people say they are allergic to colorful or scented flowers like roses. In fact, only florists, gardeners, and others who have prolonged, close contact with flowers are likely to be sensitive to pollen from these plants. Most people have little contact with the large, heavy, waxy pollen grains of such flowering plants because this type of pollen is not carried by wind but by insects such as butterflies and bees.

Evolution

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 genetic clones of themselves to float away and grow elsewhere. This is how early plants reproduced. But plants soon evolved methods of protecting these copies to deal with drying out and other damage which is even more likely on land than in the sea. The protection became the seed, though it had not yet evolved the flower. Early seed-bearing plants include the ginkgo and conifers.

Archaefructus liaoningensis
Archaefructus liaoningensis, one of the earliest known flowering plants

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. An early fossil of a flowering plant, Archaefructus liaoningensis from China, is dated about 125 million years old.[20][21] Even earlier from China is the 125–130 million years old Archaefructus sinensis. In 2015 a plant (130 million-year-old Montsechia vidalii, discovered in Spain) was claimed to be 130 million years old.[22] In 2018, scientists reported that the earliest flowers began about 180 million years ago.[23]

Amborella trichopoda (3065968016) fragment
Amborella trichopoda may have characteristic features of the earliest flowering plants

Recent DNA analysis (molecular systematics)[24] shows that Amborella trichopoda, found on the Pacific island of New Caledonia, is the only species in the sister group to the rest of the flowering plants, and morphological studies suggest that it has features which may have been characteristic of the earliest flowering plants.[25]

Besides the hard proof of flowers in or shortly before the Cretaceous,[26][27] there is some circumstantial evidence of flowers as much as 250 million years ago. A chemical used by plants to defend their flowers, oleanane, has been detected in fossil plants that old, including gigantopterids,[28] 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.

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.[29] 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".

The general assumption is that the function of flowers, from the start, was to involve 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.

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.

While many such symbiotic relationships remain too fragile to survive competition with mainland organisms, flowers proved to be an unusually effective means of production, spreading (whatever their actual origin) to become the dominant form of land plant life.

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.[30]

Color

Spectrum of Flowers(Rosa) en.pdf
Reflectance spectra for the flowers of several varieties of rose. A red rose absorbs about 99.7% of light across a broad area below the red wavelengths of the spectrum, leading to an exceptionally pure red. A yellow rose will reflect about 5% of blue light, producing an unsaturated yellow (a yellow with a degree of white in it).

Many flowering plants reflect as much light as possible within the range of visible wavelengths of the pollinator the plant intends to attract. Flowers that reflect the full range of visible light are generally perceived as white by a human observer. An important feature of white flowers is that they reflect equally across the visible spectrum. While many flowering plants use white to attract pollinators, the use of color is also widespread (even within the same species). Color allows a flowering plant to be more specific about the pollinator it seeks to attract. The color model used by human color reproduction technology (CMYK) relies on the modulation of pigments that divide the spectrum into broad areas of absorption. Flowering plants by contrast are able to shift the transition point wavelength between absorption and reflection. If it is assumed that the visual systems of most pollinators view the visible spectrum as circular then it may be said that flowering plants produce color by absorbing the light in one region of the spectrum and reflecting the light in the other region. With CMYK, color is produced as a function of the amplitude of the broad regions of absorption. Flowering plants by contrast produce color by modifying the frequency (or rather wavelength) of the light reflected. Most flowers absorb light in the blue to yellow region of the spectrum and reflect light from the green to red region of the spectrum. For many species of flowering plant, it is the transition point that characterizes the color that they produce. Color may be modulated by shifting the transition point between absorption and reflection and in this way a flowering plant may specify which pollinator it seeks to attract. Some flowering plants also have a limited ability to modulate areas of absorption. This is typically not as precise as control over wavelength. Humans observers will perceive this as degrees of saturation (the amount of white in the color).

Symbolism

Liliumbulbiferumflowertop
Lilies are often used to denote life or resurrection

Many flowers have important symbolic meanings in Western culture.[31] The practice of assigning meanings to flowers is known as floriography. Some of the more common examples include:

  • Red roses are given as a symbol of love, beauty, and passion.[32]
  • Poppies are a symbol of consolation in time of death. In the United Kingdom, New Zealand, Australia and Canada, red poppies are worn to commemorate soldiers who have died in times of war.
  • 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.
Ambrosius Bosschaert the Elder (Dutch - Flower Still Life - Google Art Project
Flowers are common subjects of still life paintings, such as this one by Ambrosius Bosschaert the Elder

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. Flowers are also dried, freeze dried and pressed in order to create permanent, three-dimensional pieces of flower art.

Flowers within art are also representative of the female genitalia,[33] as seen in the works of artists such as Georgia O'Keeffe, Imogen Cunningham, Veronica Ruiz de Velasco, and Judy Chicago, and in fact in Asian and western classical art. Many cultures around the world have a marked tendency to associate flowers with femininity.

The great variety of delicate and beautiful flowers has inspired the works of numerous poets, especially from the 18th–19th century Romantic era. Famous examples include William Wordsworth's I Wandered Lonely as a Cloud and William Blake's Ah! Sun-Flower.

Their symbolism in dreams has also been discussed, with possible interpretations including "blossoming potential".[34]

The Roman goddess of flowers, gardens, and the season of Spring is Flora. The Greek goddess of spring, flowers and nature is Chloris.

In Hindu mythology, flowers have a significant status. Vishnu, one of the three major gods in the Hindu system, is often depicted standing straight on a lotus flower.[35] Apart from the association with Vishnu, the Hindu tradition also considers the lotus to have spiritual significance.[36] For example, it figures in the Hindu stories of creation.[37]

Usage

Eastern Market Detroit flower
Flower market – Detroit's Eastern Market

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 to mark important events in their lives:

  • For new births or christenings
  • As a corsage or boutonniere worn at social functions or for holidays
  • As tokens of love or esteem
  • For wedding flowers for the bridal party, and for 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
  • For worship. In Hindu culture adherents commonly bring flowers as a gift to temples[38]
Aikya Linga in Varanasi
A woman spreading flowers over a lingam in a temple in Varanasi

People therefore grow flowers around their homes, dedicate parts of their living space to flower gardens, pick wildflowers, or buy commercially-grown flowers from florists.

Flowers provide less food than other major plant parts (seeds, fruits, roots, stems and leaves), but still provide several important vegetables and spices. Flower vegetables include broccoli, cauliflower and artichoke. The most expensive spice, saffron, consists of dried stigmas of a crocus. Other flower spices are cloves and capers. Hops flowers are used to flavor beer. Marigold flowers are fed to chickens to give their egg yolks a golden yellow color, which consumers find more desirable; dried and ground marigold flowers are also used as a spice and colouring agent in Georgian cuisine. Flowers of the dandelion and elder are often made into wine. Bee pollen, pollen collected from bees, is considered a health food by some people. Honey consists of bee-processed flower nectar and is often named for the type of flower, e.g. orange blossom honey, clover honey and tupelo honey.

Hundreds of fresh flowers are edible, but only few are widely marketed as food. They are often added to salads as garnishes. Squash blossoms are dipped in breadcrumbs and fried. Some edible flowers include nasturtium, chrysanthemum, carnation, cattail, Japanese honeysuckle, chicory, cornflower, canna, and sunflower.[39] Edible flowers such as daisy, rose, and violet are sometimes candied.[40]

Flowers such as chrysanthemum, rose, jasmine, Japanese honeysuckle, and chamomile, chosen for their fragrance and medicinal properties, are used as tisanes, either mixed with tea or on their own.[41]

Flowers have been used since prehistoric times in funeral rituals: traces of pollen have been found on a woman's tomb in the El Miron Cave in Spain.[42] Many cultures draw a connection between flowers and life and death, and because of their seasonal return flowers also suggest rebirth, which may explain why many people place flowers upon graves. The ancient Greeks, as recorded in Euripides's play The Phoenician Women, placed a crown of flowers on the head of the deceased;[43] they also covered tombs with wreaths and flower petals. Flowers were widely used in ancient Egyptian burials,[44] and the Mexicans to this day use flowers prominently in their Day of the Dead celebrations[45] in the same way that their Aztec ancestors did.

Eight Flowers, a painting by artist Qian Xuan, 13th century, Palace Museum, Beijing.
Eight Flowers, a painting by artist Qian Xuan, 13th century, Palace Museum, Beijing.

Flower-giving

The flower-giving tradition goes back to prehistoric times when flowers often had a medicinal and herbal attributes. Archeologists found in several grave sites remnants of flower petals. Apart from medical use, flowers were first used as jewellery for sacrificial and burial objects. Ancient Egyptians and later Greeks and Romans used flowers. In Egypt, burial objects from the time around 1540 BC were found, which depicted red poppy, yellow Araun, cornflower and lilies. Records of flower giving appear in Chinese writings and Egyptian hieroglyphics, as well as in Greek and Roman mythology. The practice of giving a flower flourished in the Middle Ages. The church forbade at that time couples to showing open affection in public. The couples could show their emotions for each other through flowers.

The tradition of flower-giving exists in many forms. In Russian culture flowers and the flower-giving tradition play a very important role. It is a important part of Russian folklore. It is common for students to give flowers to their teachers. To give yellow flowers in a romantic relationship means break-up in Russia. Nowadays, flowers are often given away in the form of a Flower bouquet.[46][47][48][49]

See also

References

  1. ^ a b Sattler, R. (1973). Organogenesis of Flowers. A Photographic Text-Atlas. University of Toronto Press. ISBN 978-0-8020-1864-9.
  2. ^ Reynolds, Joan; Tampion, John (1983). Double flowers: a scientific study. London: [Published for the] Polytechnic of Central London Press [by] Pembridge Press. p. 41. ISBN 978-0-86206-004-6.
  3. ^ Sattler, R. (1978). "'Fusion' and 'continuity' in floral morphology". Notes of the Royal Botanic Garden, Edinburgh. 36: 397–405.
  4. ^ Greyson, R.I. (1994). The Development of Flowers. Oxford University Press. ISBN 978-0-19-506688-3.
  5. ^ a b Leins, P. & Erbar, C. (2010). Flower and Fruit. Stuttgart: Schweizerbart Science Publishers. ISBN 978-3-510-65261-7.
  6. ^ Prenner, Gernard (February 2010). "Floral formulae updated for routine inclusion in formal taxonomic descriptions". Taxon. 59 (1): 241–250. Archived from the original on 2018-03-29.
  7. ^ a b de Craene, Louis P. Ronse (2010). Floral Diagrams. Cambridge University Press. p. 459. ISBN 9781139484558.
  8. ^ Stephen Downie; Ken Robertson. "Digital Flowers: Floral Formulas". University of Illinois. Archived from the original on 4 March 2016. Retrieved 28 January 2014.
  9. ^ Sharma, O.P. (2009). Plant Taxonomy (2nd ed.). Tata McGraw-Hill Education. pp. 165–166. ISBN 978-1259081378. Archived from the original on 2016-05-29.
  10. ^ Plant Taxonomy: Floral Formulas. St. John's University, Collegeville, MN Archived 2014-06-24 at the Wayback Machine
  11. ^ Eames, A.J. (1961). Morphology of the Angiosperms. New York: McGraw-Hill Book Co.
  12. ^ Sattler, R. (1988). "A dynamic multidimensional approach to floral development". In Leins, P.; Tucker, S.C. & Endress, P.K. Aspects of Floral Development. Berlin: J. Cramer/Borntraeger. pp. 1–6.
  13. ^ Sattler, R. & Jeune, B. (1992). "Multivariate analysis confirms the continuum view of plant form". Annals of Botany. 69: 249–262.
  14. ^ Ausín, I.; et al. (2005). "Environmental regulation of flowering". Int J Dev Biol. 49 (5–6): 689–705. doi:10.1387/ijdb.052022ia. PMID 16096975.
  15. ^ Turck, F.; Fornara, F.; Coupland, G. (2008). "Regulation and Identity of Florigen: Flowering Locus T Moves Centre Stage". Annual Review of Plant Biology. 59: 573–594. doi:10.1146/annurev.arplant.59.032607.092755. hdl:11858/00-001M-0000-0012-374F-8. PMID 18444908.
  16. ^ Searle, I.; et al. (2006). "The transcription factor FLC confers a flowering response to vernalization by repressing meristem competence and systemic signaling in Arabidopsis". Genes Dev. 20 (7): 898–912. doi:10.1101/gad.373506. PMC 1472290. PMID 16600915.
  17. ^ "Pollen Allergy". National Institute of Allergy and Infectious Diseases. Archived from the original on 2015-04-10. Retrieved 2016-05-24.
  18. ^ "Pollen Allergy" (PDF). Mass Lung & Allergy, PC. Archived from the original (PDF) on 2014-04-13. Retrieved 2014-04-10.
  19. ^ "Pollen Allergy". AccuWeather. April 14, 2010. Archived from the original on April 13, 2014.
  20. ^ Susan K. Lewis (April 17, 2007). "Flowers Modern & Ancient". PBS Online. Archived from the original on September 7, 2009. Retrieved 2010-08-30.
  21. ^ NOVA. First Flower. 2007-04-17. PBS. WGBH. |access-date= requires |url= (help)
  22. ^ Thomson, Helen (Aug 17, 2015). "Fossilised remains of world's oldest flower discovered in Spain". The Guardian. Archived from the original on 2017-03-03.
  23. ^ Chinese Academy of Sciences (18 December 2018). "Flowers originated 50 million years earlier than previously thought". EurekAlert!. Retrieved 18 December 2018.
  24. ^ Soltis, Douglas E.; Soltis, Pamela S. (2004). "Amborella not a "basal angiosperm"? Not so fast". American Journal of Botany. 91 (6): 997–1001. doi:10.3732/ajb.91.6.997. PMID 21653455. Archived from the original on 2010-06-26. Retrieved 2010-08-30.
  25. ^ "South Pacific plant may be missing link in evolution of flowering plants". Eurekalert.org. 2006-05-17. Archived from the original on 2011-05-14. Retrieved 2010-08-30.
  26. ^ Gabbott, Sarah (1 August 2017). "Did the first flower look like this?". BBC News. Archived from the original on 1 August 2017. Retrieved 1 August 2017.
  27. ^ Sauquet, Hervé; et al. (1 August 2017). "The ancestral flower of angiosperms and its early diversification". Nature Communications. 8: 16047. doi:10.1038/ncomms16047. PMC 5543309. PMID 28763051. Archived from the original on 2 August 2017. Retrieved 1 August 2017.
  28. ^ "Oily Fossils Provide Clues To The Evolution Of Flowers". Sciencedaily.com. 2001-04-05. Archived from the original on 2010-08-19. Retrieved 2010-08-30.
  29. ^ "Age-Old Question On Evolution Of Flowers Answered". Unisci.com. 2001-06-15. Archived from the original on 2010-06-10. Retrieved 2010-08-30.
  30. ^ "Human Affection Altered Evolution of Flowers". Livescience.com. Archived from the original on 2008-05-16. Retrieved 2010-08-30.
  31. ^ "The Meanings of Flowers". Flower Magazine. 2018-05-28. Retrieved 2018-12-12.
  32. ^ Audet, Marye. "Roses and Their Meaning". Archived from the original on 26 August 2014. Retrieved 22 August 2014.
  33. ^ Frownfelter, Andrea. "Flower Symbolism as Female Sexual Metaphor". Eastern Michigan University. Archived from the original on 2014-08-10.
  34. ^ Dee, Nerys (1984). Your Dreams & What They Mean. Surrey, Great Britain: Guild Publishing. p. 142.
  35. ^ "Vishnu". Bbc.co.uk. 2009-08-24. Archived from the original on 2010-10-28. Retrieved 2010-08-30.
  36. ^ "God's Favorite Flower". Hinduism Today. Archived from the original on 2009-04-13. Retrieved 2010-08-30.
  37. ^ "The Lotus". Theosociety.org. Archived from the original on 2013-06-23. Retrieved 2010-08-30.
  38. ^ "VISITING A HINDU TEMPLE; A BEGINNER'S GUIDE". Hinduism Today. April 1991.
  39. ^ Wood, Zoe (30 June 2017). "Blooming tasty – edible flowers are summer's hottest food trend". The Guardian.
  40. ^ Bradley, Sue (8 May 2015). "How to crystallise flowers like the Victorians". The Telegraph.
  41. ^ Wong, James (7 May 2017). "Grow your own herbal teas". The Guardian.
  42. ^ "Stone Age mourners 'placed flowers on graves'". The Telegraph. 10 May 2015.
  43. ^ "Burial Rites". Hellenica World. Retrieved 28 November 2018.
  44. ^ Hays, Christopher B. (2011). Death in the Iron Age II and in First Isaiah. Mohr Siebeck. p. 302. ISBN 978-3-16-150785-4.
  45. ^ Day, Frances Ann (2003). Latina and Latino Voices in Literature. Greenwood. p. 72. ISBN 978-0313323942.
  46. ^ By (2015-08-11). "The Fascinating Tradition of Giving Flowers". Flowers of the Field Las Vegas. Retrieved 2019-03-15.
  47. ^ By (2015-08-11). "The Fascinating Tradition of Giving Flowers". Flowers of the Field Las Vegas. Retrieved 2019-03-15.
  48. ^ "The Cross-Cultural Rhetoric Blog: Flowers in Russia". web.stanford.edu. Retrieved 2019-03-15.
  49. ^ "Folk Art in Russia and Ukraine | News & Info". Retrieved 2019-03-15.

Further reading

  • Buchmann, Stephen (2016). The Reason for Flowers: Their History, Culture, Biology, and How They Change Our Lives. Scribner. ISBN 978-1476755533.
  • Esau, Katherine (1965). Plant Anatomy (2nd ed.). New York: John Wiley & Sons. ISBN 978-0-471-24455-4.
  • Greyson, R.I. (1994). The Development of Flowers. Oxford University Press. ISBN 978-0-19-506688-3.
  • Leins, P. & Erbar, C. (2010). Flower and Fruit. Stuttgart: Schweizerbart Science Publishers. ISBN 978-3-510-65261-7.
  • Sattler, R. (1973). Organogenesis of Flowers. A Photographic Text-Atlas. University of Toronto Press. ISBN 978-0-8020-1864-9.

External links

Quotations related to Flowers at Wikiquote

Asteraceae

Asteraceae or Compositae (commonly referred to as the aster, daisy, composite, or sunflower family) is a very large and widespread family of flowering plants (Angiospermae).The family currently has 32,913 accepted species names, in 1,911 genera (list) and 13 subfamilies. In terms of numbers of species, the Asteraceae are rivaled only by the Orchidaceae. (Which of the two families is actually larger is unclear, owing to uncertainty about exactly how many species exist in each family.). Nearly all members bear their flowers in dense heads (capitula or pseudanthia) surrounded by involucral bracts. When viewed from a distance, each capitulum may have the appearance of being a single flower. Enlarged outer (peripheral) flowers in the capitula may resemble petals, and the involucral bracts may look like a calyx. The name Asteraceae comes from the type genus Aster, from the Ancient Greek ἀστήρ, meaning star, and refers to the star-like form of rrthe inflorescence. Compositae is an older (but still valid) name that refers to the "composite" nature of the capitula, which consist of (few to) many individual flowers.

Most members of Asteraceae are annual or perennial herbs, but a significant number are also shrubs, vines, or trees. The family has a worldwide distribution, from the polar regions to the tropics, colonizing a wide variety of habitats. It is most common in the arid and semiarid regions of subtropical and lower temperate latitudes, . The Asteraceae may represent as much as 10% of autochthonous flora in many regions of the world.

Asteraceae is an economically important family, providing products such as cooking oils, lettuce, sunflower seeds, artichokes, sweetening agents, coffee substitutes and herbal teas. Several genera are of horticultural importance, including pot marigold, Calendula officinalis, Echinacea (cone flowers), various daisies, fleabane, chrysanthemums, dahlias, zinnias, and heleniums. Asteraceae are important in herbal medicine, including Grindelia, yarrow, and many others. A number of species are considered invasive, including, most notably in North America, dandelion, which was originally introduced by European settlers who used the young leaves as a salad green.The study of this family is known as synantherology.

Chrysanthemum

Chrysanthemums (), sometimes called mums or chrysanths, are flowering plants of the genus Chrysanthemum in the family Asteraceae. They are native to Asia and northeastern Europe. Most species originate from East Asia and the center of diversity is in China. Countless horticultural varieties and cultivars exist.

Flowering plant

The flowering plants, also known as angiosperms, Angiospermae or Magnoliophyta, are the most diverse group of land plants, with 416 families, approximately 13,164 known genera and c. 369,000 known species. Like gymnosperms, angiosperms are seed-producing plants. However, they are distinguished from gymnosperms by characteristics including flowers, endosperm within the seeds, and the production of fruits that contain the seeds. Etymologically, angiosperm means a plant that produces seeds within an enclosure; in other words, a fruiting plant. The term comes from the Greek words angeion ("case" or "casing") and sperma ("seed").

The ancestors of flowering plants diverged from gymnosperms in the Triassic Period, 245 to 202 million years ago (mya), and the first flowering plants are known from 160 mya. They diversified extensively during the Early Cretaceous, became widespread by 120 mya, and replaced conifers as the dominant trees from 100 to 60 mya.

Helianthus

Helianthus or sunflower () is a genus of plants comprising about 70 species. Except for three species in South America, all Helianthus species are native to North America. The common name, "sunflower", typically refers to the popular annual species Helianthus annuus, or the common sunflower, whose round flower heads in combination with the ligules look like the sun. This and other species, notably Jerusalem artichoke (H. tuberosus), are cultivated in temperate regions and some tropical regions as food crops for humans, cattle, and poultry, and as ornamental plants.Perennial sunflower species are not as common in garden use due to their tendency to spread rapidly and become invasive. The whorled sunflower, H. verticillatus, was listed as an endangered species in 2014 when the U.S. Fish and Wildlife Service issued a final rule protecting it under the Endangered Species Act. The primary threats are industrial forestry and pine plantations in Alabama, Georgia, and Tennessee. They grow to 1.8 m (6 ft) and are primarily found in woodlands, adjacent to creeks and moist, prairie-like areas.

Hoverfly

Hoverflies, sometimes called flower flies, or syrphid flies, make up the insect family Syrphidae. As their common name suggests, they are often seen hovering or nectaring at flowers; the adults of many species feed mainly on nectar and pollen, while the larvae (maggots) eat a wide range of foods. In some species, the larvae are saprotrophs, eating decaying plant and animal matter in the soil or in ponds and streams. In other species, the larvae are insectivores and prey on aphids, thrips, and other plant-sucking insects.

Aphids alone cause tens of millions of dollars of damage to crops worldwide every year; because of this, aphid-eating hoverflies are being recognized as important natural enemies of pests, and potential agents for use in biological control. Some adult syrphid flies are important pollinators.

About 6,000 species in 200 genera have been described. Hoverflies are common throughout the world and can be found on all continents except Antarctica. Hoverflies are harmless to most other animals, despite their mimicry of more dangerous wasps and bees, which wards off predators.

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. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed. The modifications can involve the length and the nature of the internodes and the phyllotaxis, as well as variations in the proportions, compressions, swellings, adnations, connations and reduction of main and secondary axes.

Inflorescence can also be defined as the reproductive portion of a plant that bears a cluster of flowers in a specific pattern.

The stem holding the whole inflorescence is called a peduncle and the major axis (incorrectly referred to as the main stem) holding the flowers or more branches within the inflorescence is called the rachis. The stalk of each single flower is called a pedicel. A flower that is not part of an inflorescence is called a solitary flower and its stalk is also referred to as a peduncle. Any flower in an inflorescence may be referred to as a floret, especially when the individual flowers are particularly small and borne in a tight cluster, such as in a pseudanthium.

The fruiting stage of an inflorescence is known as an infructescence.

Inflorescences may be simple (single) or complex (panicle). The rachis may be one of several types, including single, composite, umbel, spike or raceme.

Iris (plant)

Iris is a genus of 260–300 species of flowering plants with showy flowers. It takes its name from the Greek word for a rainbow, which is also the name for the Greek goddess of the rainbow, Iris. Some authors state that the name refers to the wide variety of flower colors found among the many species. As well as being the scientific name, iris is also widely used as a common name for all Iris species, as well as some belonging to other closely related genera. A common name for some species is 'flags', while the plants of the subgenus Scorpiris are widely known as 'junos', particularly in horticulture. It is a popular garden flower.

The often-segregated, monotypic genera Belamcanda (blackberry lily, I. domestica), Hermodactylus (snake's head iris, I. tuberosa), and Pardanthopsis (vesper iris, I. dichotoma) are currently included in Iris.

Three Iris varieties are used in the Iris flower data set outlined by Ronald Fisher in his 1936 paper The use of multiple measurements in taxonomic problems as an example of linear discriminant analysis.

Nelumbo nucifera

Nelumbo nucifera, also known as Indian lotus, sacred lotus, bean of India, Egyptian bean or simply lotus, is one of two extant species of aquatic plant in the family Nelumbonaceae. It is often colloquially called a water lily. Under favorable circumstances the seeds of this aquatic perennial may remain viable for many years, with the oldest recorded lotus germination being from that of seeds 1,300 years old recovered from a dry lakebed in northeastern China.It has a very wide native distribution, ranging from central and northern India (at altitudes up to 1,400 m or 4,600 ft in the southern Himalayas), through northern Indochina and East Asia (north to the Amur region; the Russian populations have sometimes been referred to as "Nelumbo komarovii"), with isolated locations at the Caspian Sea. Today the species also occurs in southern India, Sri Lanka, virtually all of Southeast Asia, New Guinea and northern and eastern Australia, but this is probably the result of human translocations. It has a very long history (c. 3,000 years) of being cultivated for its edible seeds, and it is commonly cultivated in water gardens. It is the national flower of India and Vietnam.

Orchidaceae

The Orchidaceae are a diverse and widespread family of flowering plants, with blooms that are often colourful and fragrant, commonly known as the orchid family.

Along with the Asteraceae, they are one of the two largest families of flowering plants. The Orchidaceae have about 28,000 currently accepted species, distributed in about 763 genera. The determination of which family is larger is still under debate, because verified data on the members of such enormous families are continually in flux. Regardless, the number of orchid species nearly equals the number of bony fishes and is more than twice the number of bird species, and about four times the number of mammal species.

The family encompasses about 6–11% of all seed plants. The largest genera are Bulbophyllum (2,000 species), Epidendrum (1,500 species), Dendrobium (1,400 species) and Pleurothallis (1,000 species). It also includes Vanilla–the genus of the vanilla plant, the type genus Orchis, and many commonly cultivated plants such as Phalaenopsis and Cattleya. Moreover, since the introduction of tropical species into cultivation in the 19th century, horticulturists have produced more than 100,000 hybrids and cultivars.

Ornamental plant

Ornamental plants are plants that are grown for decorative purposes in gardens and landscape design projects, as houseplants, cut flowers and specimen display. The cultivation of ornamental plants is called floriculture, which forms a major branch of horticulture.

Passiflora

Passiflora, known also as the passion flowers or passion vines, is a genus of about 550 species of flowering plants, the type genus of the family Passifloraceae.

They are mostly tendril-bearing vines, with some being shrubs or trees. They can be woody or herbaceous. Passion flowers produce regular and usually showy flowers with a distinctive corona. The flower is pentamerous and ripens into an indehiscent fruit with numerous seeds. For more information about the fruit of the Passiflora plant, see passionfruit.

Perennial plant

A perennial plant or simply perennial is a plant that lives more than two years. Some sources cite perennial plants being plants that live more than three years. The term (per- + -ennial, "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also widely used to distinguish plants with little or no woody growth from trees and shrubs, which are also technically perennials.Perennials, especially small flowering plants, that grow and bloom over the spring and summer, die back every autumn and winter, and then return in the spring from their rootstock, are known as herbaceous perennials. However, depending on the rigors of local climate, a plant that is a perennial in its native habitat, or in a milder garden, may be treated by a gardener as an annual and planted out every year, from seed, from cuttings or from divisions. Tomato vines, for example, live several years in their natural tropical/subtropical habitat but are grown as annuals in temperate regions because they don't survive the winter.

There is also a class of evergreen, or non-herbaceous, perennials, including plants like Bergenia which retain a mantle of leaves throughout the year. An intermediate class of plants is known as subshrubs, which retain a vestigial woody structure in winter, e.g. Penstemon. The local climate may dictate whether plants are treated as shrubs or perennials. For instance, many varieties of Fuchsia are shrubs in warm regions, but in colder temperate climates may be cut to the ground every year as a result of winter frosts.

The symbol for a perennial plant, based on Species Plantarum by Linnaeus, is , which is also the astronomical symbol for the planet Jupiter.

Petal

Petals are modified leaves that surround the reproductive parts of flowers. They are often brightly colored or unusually shaped to attract pollinators. Together, all of the petals of a flower are called a corolla. Petals are usually accompanied by another set of special leaves called sepals, that collectively form the calyx and lie just beneath the corolla. The calyx and the corolla together make up the perianth. When the petals and sepals of a flower are difficult to distinguish, they are collectively called tepals. Examples of plants in which the term tepal is appropriate include genera such as Aloe and Tulipa. Conversely, genera such as Rosa and Phaseolus have well-distinguished sepals and petals. When the undifferentiated tepals resemble petals, they are referred to as "petaloid", as in petaloid monocots, orders of monocots with brightly coloured tepals. Since they include Liliales, an alternative name is lilioid monocots.

Although petals are usually the most conspicuous parts of animal-pollinated flowers, wind-pollinated species, such as the grasses, either have very small petals or lack them entirely.

Plant reproductive morphology

Plant reproductive morphology is the study of the physical form and structure (the morphology) of those parts of plants directly or indirectly concerned with sexual reproduction.

Among all living organisms, flowers, which are the reproductive structures of angiosperms, are the most varied physically and show a correspondingly great diversity in methods of reproduction. Plants that are not flowering plants (green algae, mosses, liverworts, hornworts, ferns and gymnosperms such as conifers) also have complex interplays between morphological adaptation and environmental factors in their sexual reproduction. The breeding system, or how the sperm from one plant fertilizes the ovum of another, depends on the reproductive morphology, and is the single most important determinant of the genetic structure of nonclonal plant populations. Christian Konrad Sprengel (1793) studied the reproduction of flowering plants and for the first time it was understood that the pollination process involved both biotic and abiotic interactions. Charles Darwin's theories of natural selection utilized this work to build his theory of evolution, which includes analysis of the coevolution of flowers and their insect pollinators.

Poppy

A poppy is a flowering plant in the subfamily Papaveroideae of the family Papaveraceae. Poppies are herbaceous plants, often grown for their colourful flowers. One species of poppy, Papaver somniferum, is the source of the narcotic drug opium which contains powerful medicinal alkaloids such as morphine and has been used since ancient times as an analgesic and narcotic medicinal and recreational drug. It also produces edible seeds. Following the trench warfare in the poppy fields of Flanders during World War I, poppies have become a symbol of remembrance of soldiers who have died during wartime.

Pseudanthium

A pseudanthium (Greek for "false flower"), also called a flower head or composite flower, is a special type of inflorescence, in which anything from a small cluster to hundreds or sometimes thousands of flowers are grouped together to form a single flower-like structure. Pseudanthia take various forms. The individual flowers of a pseudanthium commonly are called florets. The real flowers (the florets) are generally small and often greatly reduced, but the pseudanthium itself can sometimes be quite large (as in the heads of some varieties of sunflower).

Pseudanthia are characteristic of the daisy and sunflower family (Asteraceae), whose flowers are differentiated into ray flowers and disk flowers, unique to this family. The disk flowers in the center of the pseudanthium are actinomorphic and the corolla is fused into a tube. Flowers on the periphery are zygomorphic and the corolla has one large lobe (the so-called "petals" of a daisy are individual ray flowers, for example). Either ray or disk flowers may be absent in some plants: Senecio vulgaris lacks ray flowers and Taraxacum officinale lacks disk flowers. The pseudanthium has a whorl of bracts below the flowers, forming an involucre.

In all cases, a pseudanthium (inflorescence) is superficially indistinguishable from a flower, but closer inspection of its anatomy will reveal that it is composed of multiple flowers. Thus, the pseudanthium represents an evolutionary convergence of the inflorescence to a reduced reproductive unit that may function in pollination like a single flower, at least in plants that are animal pollinated.

Sepal

A sepal ( or ) is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom. The term sepalum was coined by Noël Martin Joseph de Necker in 1790, and derived from the Greek σκεπη (skepi), a covering.Collectively the sepals are called the calyx (plural calyces), the outermost whorl of parts that form a flower. The word calyx was adopted from the Latin calyx, not to be confused with calix, a cup or goblet. Calyx derived from the Greek κάλυξ (kalyx), a bud, a calyx, a husk or wrapping, (cf Sanskrit kalika, a bud) while calix derived from the Greek κυλιξ (kylix), a cup or goblet, and the words have been used interchangeably in botanical Latin.After flowering, most plants have no more use for the calyx which withers or becomes vestigial. Some plants retain a thorny calyx, either dried or live, as protection for the fruit or seeds. Examples include species of Acaena, some of the Solanaceae (for example the Tomatillo, Physalis philadelphica), and the water caltrop, Trapa natans. In some species the calyx not only persists after flowering, but instead of withering, begins to grow until it forms a bladder-like enclosure around the fruit. This is an effective protection against some kinds of birds and insects, for example in Hibiscus trionum and the Cape gooseberry.

Morphologically, both sepals and petals are modified leaves. The calyx (the sepals) and the corolla (the petals) are the outer sterile whorls of the flower, which together form what is known as the perianth.The term tepal is usually applied when the parts of the perianth are difficult to distinguish, e.g. the petals and sepals share the same color, or the petals are absent and the sepals are colorful. When the undifferentiated tepals resemble petals, they are referred to as "petaloid", as in petaloid monocots, orders of monocots with brightly coloured tepals. Since they include Liliales, an alternative name is lilioid monocots. Examples of plants in which the term tepal is appropriate include genera such as Aloe and Tulipa. In contrast, genera such as Rosa and Phaseolus have well-distinguished sepals and petals.The number of sepals in a flower is its merosity. Flower merosity is indicative of a plant's classification. The merosity of a eudicot flower is typically four or five. The merosity of a monocot or palaeodicot flower is three, or a multiple of three.

The development and form of the sepals vary considerably among flowering plants. They may be free (polysepalous) or fused together (gamosepalous). Often, the sepals are much reduced, appearing somewhat awn-like, or as scales, teeth, or ridges. Most often such structures protrude until the fruit is mature and falls off.

Examples of flowers with much reduced perianths are found among the grasses.

In some flowers, the sepals are fused towards the base, forming a calyx tube (as in the Lythraceae family, and Fabaceae). In other flowers (e.g., Rosaceae, Myrtaceae) a hypanthium includes the bases of sepals, petals, and the attachment points of the stamens.

Stamen

The stamen (plural stamina or stamens) is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium.

Super Mario

Super Mario is a series of fantasy platform games created by Nintendo featuring their mascot, Mario. Alternatively called the Super Mario Bros. series or simply the Mario series, it is the central series of the greater Mario franchise. At least one Super Mario game has been released for every major Nintendo video game console.

The Super Mario games follow Mario's adventures, typically in the fictional Mushroom Kingdom with Mario as the player character. He is often joined by his brother, Luigi, and occasionally by other members of the Mario cast. As in platform video games, the player runs and jumps across platforms and atop enemies in themed levels. The games have simple plots, typically with Mario rescuing the kidnapped Princess Peach from the primary antagonist, Bowser. The first title in the series, Super Mario Bros., released for the Nintendo Entertainment System (NES) in 1985, established gameplay concepts and elements prevalent in nearly every Super Mario game since. These include a multitude of power-ups and items that give Mario special magic powers such as fireball-throwing and size-changing into giant and miniature sizes.The Super Mario series is part of the greater Mario franchise. This includes other video game genres as well as media such as film, television, printed media and merchandise. Over 310 million copies of games in the Super Mario series have been sold worldwide, as of September 2015, making it the best-selling video game series in history.

Subdisciplines
Plant groups
Plant morphology
(glossary)
Plant growth and habit
Reproduction
Plant taxonomy
Practice
  • Lists
  • Related topics
Academic
disciplines
Groups
Related

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.