Array ( [0] => {{Short description|Reproductive structure in flowering plants}} [1] => {{other uses}} [2] => {{redirect|Floral}} [3] => {{pp-semi-indef|small=yes}} [4] => [[File:Flower poster 2.jpg|thumb|upright=1.5]] [5] => A '''flower''', also known as a '''bloom''' or '''blossom''', is the reproductive structure found in [[flowering plant]]s (plants of the division [[Angiospermae]]). Flowers consist of a combination of vegetative organs – [[sepals]] that enclose and protect the developing flower, petals that attract pollinators, and reproductive organs that produce [[gametophyte]]s, which in flowering plants produce [[gametes]]. The male gametophytes, which produce sperm, are enclosed within pollen grains produced in the [[Stamen|anthers]]. The female gametophytes are contained within the [[Gynoecium#The ovule|ovules]] produced in the [[Gynoecium#Carpels|carpels]]. [6] => [7] => Most flowering plants depend on animals, such as [[bee]]s, [[moth]]s, and [[butterflies]], to transfer their pollen between different flowers, and have evolved to attract these [[pollinator]]s by various strategies, including brightly colored, conspicuous petals, attractive scents, and the production of [[nectar]], a food source for pollinators.{{cite web |title=Plant Pollination Strategies |url=https://www.fs.usda.gov/wildflowers/pollinators/Plant_Strategies/index.shtml |website=US Forest Service |date=12 December 2022 |access-date=16 February 2023 |url-status=live |archive-url=https://web.archive.org/web/20230216223224/https://www.fs.usda.gov/wildflowers/pollinators/Plant_Strategies/index.shtml |archive-date=Feb 16, 2023}} In this way, many flowering plants have [[Co-evolution|co-evolved]] with pollinators to be mutually dependent on services they provide to one another—in the plant's case, a means of reproduction; in the pollinator's case, a source of food.{{cite web |title=Pollinators in the Landscape II: Plants and Pollinators |url=https://ag.umass.edu/landscape/fact-sheets/pollinators-in-landscape-ii-plants-pollinators |date=9 September 2015 |publisher=Center for Agriculture, Food, and the Environment at University of Massachusetts Amherst |first1=Mandy |last1=Bayer |url-status=live |archive-url=https://web.archive.org/web/20240107212549/https://ag.umass.edu/landscape/fact-sheets/pollinators-in-landscape-ii-plants-pollinators |archive-date=Jan 7, 2024}} [8] => [9] => When [[pollen]] from the [[anther]] of a flower is deposited on the [[Stigma (botany)|stigma]], this is called [[pollination]]. Some flowers may [[self-pollination|self-pollinate]], producing seed using pollen from a different flower of the same plant, but others have mechanisms to prevent self-pollination and rely on [[Pollination#Mechanism|cross-pollination]], when pollen is transferred from the anther of one flower to the stigma of another flower on a different individual of the same [[species]]. Self-pollination happens in flowers where the [[stamen]] and [[carpel]] mature at the same time, and are positioned so that the pollen can land on the flower's stigma. This pollination does not require an investment from the plant to provide nectar and pollen as food for pollinators.{{Cite web |url=https://courses.lumenlearning.com/wm-biology2/chapter/self-pollination-and-cross-pollination/ |title=Self-Pollination and Cross-Pollination | Biology for Majors II |website=Lumen Learning |access-date=2020-07-21 |archive-date=2020-07-21 |archive-url=https://web.archive.org/web/20200721145554/https://courses.lumenlearning.com/wm-biology2/chapter/self-pollination-and-cross-pollination/ |url-status=live}} Some flowers produce [[Diaspore (botany)|diaspores]] without fertilization ([[parthenocarpy]]). After fertilization, the [[Ovary (botany)|ovary]] of the flower develops into [[fruit]] containing [[seed]]s. [10] => [11] => Flowers have long been appreciated by humans for their beauty and pleasant scents, and also hold cultural significance as religious, ritual, or symbolic objects, or sources of [[Medicinal plants|medicine]] and [[food]]. [12] => [13] => == Etymology == [14] => Flower is from the [[Middle English]] {{lang-enm|flour|label=none}}, which referred to both the [[Flour|ground grain]] and the reproductive structure in plants, before splitting off in the 17th century. It comes originally from the [[Latin]] name of the Italian goddess of flowers, [[Flora (mythology)|Flora]]. The early word for flower in English was ''blossom'',{{Cite book |last=Cresswell |first=Julia |url=http://archive.org/details/oxforddictionary0000unse_p6k3 |title=Oxford dictionary of word origins |publisher=[[Oxford University Press]] |others=Internet Archive |year=2010 |isbn=978-0-19-954793-7 |pages=165 & 172}} though it now refers to flowers only of [[fruit tree]]s.{{Cite web |title=Definition of BLOSSOM |url=https://www.merriam-webster.com/dictionary/blossom |access-date=2021-06-16 |website=www.merriam-webster.com |language=en |archive-date=2021-06-24 |archive-url=https://web.archive.org/web/20210624195309/https://www.merriam-webster.com/dictionary/blossom |url-status=live}} [15] => [16] => ==Morphology== [17] => [[File:Mature flower diagram.svg|thumb|right|Diagram of flower parts.|389x389px]]{{Main|Floral morphology}} [18] => {{anchor|Floral morphology}} [19] => [20] => The [[Morphology (biology)|morphology]] of a flower, or its form and structure,{{Cite web |title=Morphology {{!}} Definition of Morphology by Oxford Dictionary on Lexico.com also meaning of Morphology |url=https://www.lexico.com/definition/morphology |archive-url=https://web.archive.org/web/20200305173019/https://www.lexico.com/definition/morphology |url-status=dead |archive-date=March 5, 2020 |access-date=2021-07-08 |website=Lexico Dictionaries {{!}} English |language=en}} can be considered in two parts: the vegetative part, consisting of non-reproductive structures such as [[petal]]s; and the reproductive or sexual parts. A stereotypical flower is made up of four kinds of structures attached to the tip of a short stalk or axis, called a [[Receptacle (botany)|receptacle]]. Each of these parts or floral organs is arranged in a spiral called a [[Whorl (botany)|whorl]].{{Sfn|De Craene|P.|2010|p=4}} The four main whorls (starting from the base of the flower or lowest node and working upwards) are the [[Calyx (botany)|calyx]], [[Corolla (botany)|corolla]], [[androecium]], and [[gynoecium]]. Together the calyx and corolla make up the non-reproductive part of the flower called the [[perianth]], and in some cases may not be differentiated. If this is the case, then they are described as [[tepals]].{{Sfn|De Craene|P.|2010|pp=5–6}} [21] => [22] => === Perianth === [23] => {{Main|Perianth}} [24] => [25] => ==== Calyx ==== [26] => The [[sepal]]s, collectively called the calyx, are modified [[Leaf|leaves]] that occur on the outermost whorl of the flower. They are leaf-like, in that they have a broad base, [[stoma]]ta and [[chlorophyll]]{{Sfn|De Craene|P.|2010|p=7}} and may have [[stipules]]. Sepals are often waxy and tough, and grow quickly to protect the flower as it develops.{{Sfn|De Craene|P.|2010|p=7}}{{Sfn|D. Mauseth|2016|p=225}} They may be [[deciduous]], but will more commonly grow on to assist in fruit dispersal. If the calyx is fused together it is called gamosepalous.{{Sfn|De Craene|P.|2010|p=7}} [27] => [28] => ==== Corolla ==== [29] => [30] => The [[petal]]s, together the corolla, are almost or completely fiberless leaf-like structures that form the innermost whorl of the perianth. They are often delicate and thin, and are usually coloured, shaped, or scented to encourage pollination.{{Sfn|D. Mauseth|2016|p=226}} Although similar to leaves in shape, they are more comparable to stamens in that they form almost simultaneously with one another, but their subsequent growth is delayed. If the corolla is fused together it is called sympetalous.{{Sfn|De Craene|P.|2010|p=8}} [31] => [32] => === Reproductive === [33] => {{Main|Plant reproductive morphology}} [34] => [[File:Lillium_Stamens.jpg|thumb|Reproductive parts of Easter Lily (''[[Lilium longiflorum]]''). 1. Stigma, 2. Style, 3. Stamens, 4. Filament, 5. Petal]] [35] => [36] => ==== Androecium ==== [37] => The [[androecium]], or stamens, is the whorl of pollen-producing male parts. Stamens consist typically of an anther, made up of four pollen sacs arranged in two [[theca]]e, connected to a filament, or stalk. The anther contains microsporocytes which become [[pollen]], the male [[gametophyte]], after undergoing [[meiosis]]. Although they exhibit the widest variation among floral organs, the androecium is usually confined just to one whorl and to two whorls only in rare cases. Stamens range in number, size, shape, orientation, and in their point of connection to the flower.{{Sfn|D. Mauseth|2016|p=226}}{{Sfn|De Craene|P.|2010|p=8}} [38] => [39] => In general, there is only one type of stamen, but there are plant species where the flowers have two types; a "normal" one and one with anthers that produce sterile pollen meant to attract pollinators.[https://books.google.com/books?id=pxRREAAAQBAJ&dq=%22flowers+with+two+kinds+of+stamen%22&pg=PA320 Insect-Plant Biology] [40] => [41] => ==== Gynoecium ==== [42] => The [[gynoecium]], or the carpels, is the female part of the flower found on the innermost whorl. Each carpel consists of a [[Stigma (botany)|stigma]], which receives pollen, a style, which acts as a stalk, and an [[Ovary (botany)|ovary]], which contains the ovules. Carpels may occur in one to several whorls, and when fused are often described as a pistil. Inside the ovary, the [[ovule]]s are attached to the [[Placentation#In plants|placenta]] by structures called ''funiculi''.{{Sfn|D. Mauseth|2016|p=229}}{{Sfn|De Craene|P.|2010|p=14}} [43] => [44] => === Variation === [45] => Although this arrangement is considered "typical", plant species show a wide variation in floral structure.{{cite book |last=Sattler |first=R. |date=1973 |title=Organogenesis of Flowers. A Photographic Text-Atlas |publisher=University of Toronto Press |isbn=978-0-8020-1864-9}} The four main parts of a flower are generally defined by their positions on the receptacle and not by their function. Many flowers lack some parts or parts may be modified into other functions or look like what is typically another part.{{Cite book |last=Endress |first=Peter K. |url=https://books.google.com/books?id=8_DfMSS9r9cC |title=Diversity and Evolutionary Biology of Tropical Flowers |date=1996-07-25 |publisher=Cambridge University Press |isbn=978-0-521-56510-3 |pages=11 |language=en}} In some families, such as the [[Poaceae|grasses]], the petals are greatly reduced; in many species, the sepals are colorful and petal-like. Other flowers have modified stamens that are petal-like; the double flowers of [[Peonie]]s and [[Rose]]s are mostly petaloid stamens.{{Cite book |author1=Reynolds, Joan |author2=Tampion, John |title=Double flowers: a scientific study |year=1983 |publisher=[Published for the] Polytechnic of Central London Press [by] Pembridge Press |location=London |isbn=978-0-86206-004-6 |page=41}} [46] => [47] => Many flowers have [[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. This is an example of [[radial symmetry]]. When flowers are bisected and produce only one line that produces symmetrical halves, the flower is said to be irregular or [[zygomorphic]]. If, in rare cases, they have no symmetry at all they are called asymmetric.{{Sfn|De Craene|P.|2010|p=25}}{{cite book |last1=Weberling |first1=Focko |url=https://books.google.com/books?id=-ZlOAAAAIAAJ&q=valerian+flower+symmetry&pg=PA19 |title=Morphology of Flowers and Inflorescences |date=1992 |publisher=Cambridge University Press |isbn=0-521-25134-6 |pages=17–19}} [48] => [49] => Flowers may be directly attached to the plant at their base ([[Sessility (botany)|sessile]]—the supporting stalk or stem is highly reduced or absent).{{Sfn|D. Mauseth|2016|p=243}} The stem or stalk subtending a flower, or an [[inflorescence]] of flowers, is called a [[peduncle (botany)|peduncle]]. If a peduncle supports more than one flower, the stems connecting each flower to the main axis are called [[pedicel (botany)|pedicels]].{{Sfn|De Craene|P.|2010|p=410}} The apex of a flowering stem forms a terminal swelling which is called the torus or receptacle. [50] => [51] => In the majority of species, individual flowers have both [[pistil]]s and stamens. These flowers are described by botanists as being perfect, bisexual, or [[Hermaphrodite#Plants|hermaphrodite]]. In some species of plants, the flowers are imperfect or unisexual: having only either male (stamens) or female (pistil) parts. If unisexual male and female flowers appear on the same plant, the species is called [[Monoecy|monoecious]].{{Sfn|D. Mauseth|2016|p=239}} However, if an individual plant is either female or male, the species is called [[Dioecy|dioecious]]. Many flowers have [[nectaries]], which are glands that produce a sugary fluid used to attract pollinators. They are not considered as an organ on their own.{{Sfn|De Craene|P.|2010|p=21}} [52] => [53] => ==== Inflorescence ==== [54] => {{Main|Inflorescence}} [55] => [[File:White and yellow flower.JPG|thumb|right|The [[Zantedeschia aethiopica|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]].{{Cite web |title=Zantedeschia aethiopica |url=https://www.nzpcn.org.nz/flora/species/zantedeschia-aethiopica/ |access-date=2022-05-08 |website=New Zealand Plant Conservation Network |language=en}}]]In those species that have more than one flower on an axis, the collective cluster of flowers is called an [[inflorescence]]. Some inflorescences are composed of many small flowers arranged in a formation that resembles a single flower. A common example of this is most members of the very large composite ([[Asteraceae]]) group. A single [[Asteraceae|daisy]] or [[sunflower]], for example, is not a flower but a flower [[head (botany)|head]]—an inflorescence composed of numerous flowers (or florets).{{Sfn|D. Mauseth|2016|p=228}} An inflorescence may include specialized stems and modified leaves known as [[bract]]s.{{Sfn|De Craene|P.|2010|pp=22–24}} [56] => [57] => ==== Floral diagrams and formulae ==== [58] => {{main|Floral formula|Floral diagram}} [59] => 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.{{cite journal |last=Prenner |first=Gernard |title=Floral formulae updated for routine inclusion in formal taxonomic descriptions |journal=Taxon |date=February 2010 |volume=59 |issue=1 |pages=241–250 |url=https://www.academia.edu/1175371 |url-status=live |archive-url=https://web.archive.org/web/20180329233442/http://www.academia.edu/1175371/Floral_formulae_updated_for_routine_inclusion_in_formal_taxonomic_descriptions |archive-date=2018-03-29 |doi=10.1002/tax.591022}} The format of floral formulae differs in different parts of the world, yet they convey the same information.{{Sfn|De Craene|P.|2010|p=38}}{{cite web |title=Digital Flowers: Floral Formulas |url=http://www.life.illinois.edu/help/digitalflowers/FloralFormulas/index.htm |publisher=University of Illinois |access-date=28 January 2014 |author=Stephen Downie |author2=Ken Robertson |url-status=live |archive-url=https://web.archive.org/web/20160304195425/http://www.life.illinois.edu/help/digitalflowers/FloralFormulas/index.htm |archive-date=4 March 2016}}{{Cite web |url=http://employees.csbsju.edu/ssaupe/biol308/Lecture/floral_form.htm |archive-url=https://web.archive.org/web/20140624001630/http://employees.csbsju.edu/ssaupe/biol308/Lecture/floral_form.htm |url-status=dead |title=Plant Taxonomy - Biology 308 |archive-date=Jun 24, 2014 |website=employees.csbsju.edu}}{{Sfn|Sharma|2009|pp=165–166}} [60] => [61] => The structure of a flower can also be expressed by the means of [[floral diagram]]s. 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.{{Sfn|De Craene|P.|2010|p=36}} [62] => [63] => ==Development== [64] => 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 [[leaf|leaves]].{{cite book |last=Eames |first=A.J. |date=1961 |title=Morphology of the Angiosperms |url=https://archive.org/details/morphologyofangi0000eame |url-access=registration |publisher=McGraw-Hill Book Co. |location=New York}} Detailed developmental studies, however, have shown that stamens are often initiated more or less like [[Aerial stem modification|modified stems]] (caulomes) that in some cases may even resemble [[branchlet]]s.{{Cite book |last=Leins |first=Peter |url=https://www.worldcat.org/oclc/678542669 |title=Flower and fruit : morphology, ontogeny, phylogeny, function and ecology |date=2010 |publisher=Schweizerbart |others=Claudia Erbar |isbn=978-3-510-65261-7 |location=Stuttgart |oclc=678542669}} 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).{{cite book |last=Sattler |first=R. |date=1988 |chapter=A dynamic multidimensional approach to floral development |editor1-last=Leins |editor1-first=P. |editor2-last=Tucker |editor2-first=S.C. |name-list-style=amp |editor3-last=Endress |editor3-first=P.K. |title=Aspects of Floral Development |location=Berlin |publisher=J. Cramer/Borntraeger |pages=1–6}}{{cite journal |last1=Sattler |first1=R. |name-list-style=amp |last2=Jeune |first2=B. |date=1992 |title=Multivariate analysis confirms the continuum view of plant form |journal=Annals of Botany |volume=69 |issue=3 |pages=249–262 |doi=10.1093/oxfordjournals.aob.a088338}} [65] => [66] => ===Transition=== [67] => 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.{{cite journal |author=Ausín, I. |year=2005 |title=Environmental regulation of flowering |journal=Int J Dev Biol |volume=49 |pages=689–705 |doi=10.1387/ijdb.052022ia |pmid=16096975 |issue=5–6 |display-authors=etal |doi-access=free}} Many [[Perennial plant|perennial]] and most [[Biennial plant|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 [[gene]]s, including Constans, Flowering Locus C, and Flowering Locus T. Florigen is produced in the leaves in reproductively favorable conditions and acts in [[bud]]s and growing tips to induce a number of different physiological and morphological changes.{{cite journal |author1=Turck, F. |author2=Fornara, F. |author3=Coupland, G. |year=2008 |title=Regulation and Identity of Florigen: Flowering Locus T Moves Centre Stage |journal=Annual Review of Plant Biology |volume=59 |pages=573–594 |doi=10.1146/annurev.arplant.59.032607.092755 |pmid=18444908 |hdl=11858/00-001M-0000-0012-374F-8 |s2cid=39798675 |url=http://edoc.mpg.de/359549 |hdl-access=free |access-date=2019-07-23 |archive-date=2019-12-15 |archive-url=https://web.archive.org/web/20191215213503/http://edoc.mpg.de/359549 |url-status=live}}[[File:ABC flower development.svg|thumb|upright|The ABC model of flower development]]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 [[carpel]]s. 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.{{cite journal |author=Searle, I. |year=2006 |title=The transcription factor FLC confers a flowering response to vernalization by repressing meristem competence and systemic signaling in Arabidopsis |journal=Genes Dev. |volume=20 |pages=898–912 |doi=10.1101/gad.373506 |pmid=16600915 |issue=7 |pmc=1472290 |display-authors=etal}} [68] => [69] => ===Organ development=== [70] => {{main|ABC model of flower development}} [71] => The ABC model is a simple model that describes the [[gene]]s responsible for the development of flowers. Three gene activities interact in a combinatorial manner to determine the developmental identities of the [[Primordium|primordia]] organ within the floral [[meristem|apical meristem]]. These gene functions are called A, B, and C. A genes are expressed in only outer and lower most section of the apical meristem, which becomes a whorl of sepals. In the second whorl both A and B genes are expressed, leading to the formation of petals. In the third whorl, B and C genes interact to form stamens and in the center of the flower C genes alone give rise to carpels. The model is based upon studies of aberrant flowers and mutations in ''[[Arabidopsis thaliana]]'' and the snapdragon, ''[[Antirrhinum majus]]''. For example, when there 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.{{Sfn|D. Mauseth|2016|pp=392–395}} [72] => [73] => == Function == [74] => {{See also|Plant reproductive morphology}} [75] => The principal purpose of a flower is the reproduction{{Cite journal |last1=Beekman |first1=Madeleine |last2=Nieuwenhuis |first2=Bart |last3=Ortiz-Barrientos |first3=Daniel |last4=Evans |first4=Jonathan P. |date=2016 |title=Sexual selection in hermaphrodites, sperm and broadcast spawners, plants and fungi |journal=Philosophical Transactions: Biological Sciences |volume=371 |issue=1706 |pages=5 |doi=10.1098/rstb.2015.0541 |jstor=26143395 |pmid=27619704 |pmc=5031625 |issn=0962-8436 |quote="The sole purpose of flowers is sex."}} of the individual and the species. All flowering plants are ''[[Heterospory|heterosporous]]'', that is, every individual plant produces two types of [[spore]]s. Microspores are produced by [[meiosis]] inside anthers and megaspores are produced inside ovules that are within an ovary. Anthers typically consist of four microsporangia and an ovule is an integumented megasporangium. Both types of spores develop into [[gametophyte]]s inside sporangia. As with all heterosporous plants, the gametophytes also develop inside the spores, i. e., they are endosporic. [76] => [77] => == Pollination == [78] => {{main|Pollination}}{{Multiple image [79] => | image2 = Bees Collecting Pollen cropped.jpg [80] => | caption2 = Grains of pollen sticking to this bee will be transferred to the next flower it visits. [81] => | width = 200 [82] => }} [83] => Since the flowers are the reproductive organs of the plant, they mediate the joining of the sperm, contained within pollen, to the ovules — contained in the ovary.{{Sfn|D. Mauseth|2016|p=225}} Pollination is the movement of pollen from the anthers to the stigma.{{Sfn|Walker|2020|p=9}} Normally pollen is moved from one plant to another, known as [[cross-pollination]], but many plants are able to self-pollinate. Cross-pollination is preferred because it allows for [[genetic variation]], which contributes to the survival of the species.{{Sfn|D. Mauseth|2016|pp=|p=238}} Many flowers depend on external factors for pollination, such as: the wind, water, animals, and especially [[insect]]s. Larger animals such as birds, bats, and even some [[pygmy possum]]s,{{Cite journal |last=Turner |first=Vivienne |date=1984 |title=Banksia Pollen as a Source of Protein in the Diet of Two Australian Marsupials Cercartetus nanus and Tarsipes rostratus |url=https://www.jstor.org/stable/3544245 |journal=Oikos |volume=43 |issue=1 |pages=53–61 |doi=10.2307/3544245 |jstor=3544245 |issn=0030-1299 |quote=[T]he honey possum, Tarsipes rostratus (Turner 1983). This marsupial is highly specialized for feeding at flowers and known to visit several species of Banksia |via=[[JSTOR]] |access-date=2021-06-20 |archive-date=2021-06-24 |archive-url=https://web.archive.org/web/20210624215040/https://www.jstor.org/stable/3544245 |url-status=live}} however, can also be employed.{{Sfn|Walker|2020|p=65}}{{Sfn|Walker|2020|pp=69–83}} To accomplish this, flowers have specific designs which encourage the transfer of pollen from one plant to another of the same species. The period of time during which this process can take place (when the flower is fully expanded and functional) is called ''[[anthesis]]'',{{Sfn|Walker|2020|p=120}} hence the study of pollination biology is called ''[[anthecology]]''.{{Cite book |last=Baker |first=Herbert G. |date=1983-01-01 |title=An Outline of the History of Anthecology, or Pollination Biology |chapter=CHAPTER 2 - an Outline of the History of Anthecology, or Pollination Biology**Based on, but expanded and updated from, a paper published in the N.Z. J. Bot. (Baker, 1979), by permission of the editor |chapter-url=https://www.sciencedirect.com/science/article/pii/B9780125839808500090 |journal=Pollination Biology |language=en |page=8 |doi=10.1016/B978-0-12-583980-8.50009-0 |isbn=9780125839808 |via=[[Elsevier Science Direct]] |access-date=2021-06-20 |archive-date=2021-06-24 |archive-url=https://web.archive.org/web/20210624201108/https://www.sciencedirect.com/science/article/pii/B9780125839808500090 |url-status=live}} [84] => [85] => Flowering plants usually face [[evolutionary pressure]] to optimize the transfer of their [[pollen]], and this is typically reflected in the morphology of the flowers and the behavior of the plants.{{Cite journal |last=Friedman |first=Jannice |date=2011 |title=Gone with the wind: understanding evolutionary transitions between wind and animal pollination in the angiosperms |journal=The New Phytologist |volume=191 |issue=4 |pages=911–913 |doi=10.1111/j.1469-8137.2011.03845.x |jstor=20869225 |pmid=21834912 |issn=0028-646X |doi-access=free}} Pollen may be transferred between plants via a number of 'vectors,' or methods. Around 80% of flowering plants make use of biotic, or living vectors. Others use abiotic, or non-living, vectors and some plants make use of multiple vectors, but most are highly specialised.{{Cite journal |last=Ackerman |first=J. D. |date=2000-03-01 |title=Abiotic pollen and pollination: Ecological, functional, and evolutionary perspectives |url=https://doi.org/10.1007/BF00984101 |journal=Plant Systematics and Evolution |language=en |volume=222 |issue=1 |pages=167–185 |doi=10.1007/BF00984101 |s2cid=36015720 |issn=1615-6110 |access-date=2021-06-20 |archive-date=2022-02-21 |archive-url=https://web.archive.org/web/20220221171454/https://link.springer.com/article/10.1007/BF00984101 |url-status=live}} [86] => [87] => Though some fit between or outside of these groups,{{Sfn|Walker|2020|p=46}} most flowers can be divided between the following two broad groups of pollination methods: [88] => [89] => === Biotic pollination === [90] => Flowers that use biotic vectors attract and use [[insect]]s, [[bat]]s, [[bird]]s, or other animals to transfer pollen from one flower to the next. Often they are [[Generalist and specialist species|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).{{Sfn|D. Mauseth|2016|pp=239–240}} 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.{{Sfn|Walker|2020|p=68}} Many flowers rely on simple proximity between flower parts to ensure pollination, while others have elaborate designs to ensure pollination and prevent [[self-pollination]].{{Sfn|D. Mauseth|2016|pp=|p=238}} Flowers use animals including: insects (''[[entomophily]]''), birds (''[[ornithophily]]''), bats (''[[chiropterophily]]''), lizards,{{Sfn|Walker|2020|pp=69–83}} and even snails and slugs (''malacophilae'').{{Sfn|Knuth|Müller|Ainsworth Davis|1906|pp=72–80}} [91] => [92] => ==== Attraction methods ==== [93] => [[File:Ophrys apifera flower1.jpg|thumb|''[[Ophrys apifera]]'', a bee orchid, which has evolved over many generations to mimic a female bee.{{Cite journal |last1=Vereecken |first1=Nicolas J. |last2=Wilson |first2=Carol A. |last3=Hötling |first3=Susann |last4=Schulz |first4=Stefan |last5=Banketov |first5=Sergey A. |last6=Mardulyn |first6=Patrick |date=2012-12-07 |title=Pre-adaptations and the evolution of pollination by sexual deception: Cope's rule of specialization revisited |journal=Proceedings of the Royal Society B: Biological Sciences |volume=279 |issue=1748 |pages=4786–4794 |doi=10.1098/rspb.2012.1804 |pmc=3497092 |pmid=23055065}}|273x273px]] [94] => Plants cannot move from one location to another, thus many flowers have evolved to attract animals to transfer pollen between individuals in dispersed populations. Most commonly, flowers are insect-pollinated, known as ''[[Entomophily|entomophilous]]''; literally "insect-loving" in Greek.{{Sfn|Walker|2020|p=81}} To attract these insects flowers commonly have glands called ''nectaries'' on various parts that attract animals looking for nutritious [[nectar]].{{Sfn|Walker|2020|pp=112–113}} Some flowers have glands called [[elaiophore]]s, which produce oils rather than nectar.{{cite journal |last1=Schäffler |first1=Irmgard |last2=Dötterl |first2=Stefan |title=A day in the life of an oil bee: phenology, nesting, and foraging behavior |journal=Apidologie |date=2011 |volume=42 |issue=3 |pages=409–424 |doi=10.1007/s13592-011-0010-3 |s2cid=29392750 |url=https://hal.archives-ouvertes.fr/hal-01003522/file/hal-01003522.pdf}} Birds and bees have [[color vision]], enabling them to seek out colorful flowers.{{Sfn|Walker|2020|pp=107–108}} Some flowers have patterns, called [[nectar guide]]s, 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.{{Sfn|Walker|2020|p=121}} [95] => [96] => Flowers also attract pollinators by [[Floral scent|scent]], though 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. These are often called [[Carrion flower]]s, including plants in the genus ''[[Rafflesia]]'', and the [[titan arum]].{{Sfn|Walker|2020|pp=107–108}} Flowers pollinated by night visitors, including bats and moths, are likely to concentrate on scent to attract pollinators and so most such flowers are white.{{Sfn|Walker|2020|p=173}} Some plants pollinated by bats have a sonar-reflecting petal above its flowers, which helps the bat find them,[https://www.livescience.com/15279-bat-flower-echo-acoustics-sonar-leaf.html Holy Talking Plant! Flower Communicates with Bats] and one species, the cactus ''Espostoa frutescens'', has flowers that are surrounded by an area of sound-absorbent and wooly hairs called the cephalium, which absorbs the bat's ultrasound instead.[https://www.the-scientist.com/news-opinion/ecuadorian-cactus-absorbs-ultrasound--enticing-bats-to-flowers-66981 Ecuadorian Cactus Absorbs Ultrasound, Enticing Bats to Flowers] [97] => [98] => Flowers are also specialized in shape and have an arrangement of the [[stamen]]s that ensures that pollen grains are transferred to the bodies of the pollinator when it lands in search of its attractant. Other flowers use mimicry or [[pseudocopulation]] to attract pollinators. Many orchids for example, produce flowers resembling female bees or wasps in colour, shape, and scent. Males move from one flower to the next in search of a mate, pollinating the flowers.{{Sfn|D. Mauseth|2016|pp=|p=241}}{{Cite journal |last1=Peakall |first1=Rod |last2=Ebert |first2=Daniel |last3=Poldy |first3=Jacqueline |last4=Barrow |first4=Russell A. |last5=Francke |first5=Wittko |last6=Bower |first6=Colin C. |last7=Schiestl |first7=Florian P. |date=2010 |title=Pollinator specificity, floral odour chemistry and the phylogeny of Australian sexually deceptive Chiloglottis orchids: implications for pollinator-driven speciation |journal=New Phytologist |language=en |volume=188 |issue=2 |pages=437–450 |doi=10.1111/j.1469-8137.2010.03308.x |pmid=20561345 |issn=1469-8137 |doi-access=free}} [99] => [100] => ==== Pollinator relationships ==== [101] => {{further|Pollination syndrome}} [102] => 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 an example of [[coevolution]], as the flower and pollinator have developed together over a long period of time to match each other's needs.{{Sfn|D. Mauseth|2016|pp=240}} This close relationship compounds the negative effects of [[extinction]], however, since the extinction of either member in such a relationship would almost certainly mean the extinction of the other member as well.{{Cite journal |last=Bawa |first=K. S. |date=1990 |title=Plant-Pollinator Interactions in Tropical Rain Forests |url=https://www.jstor.org/stable/2097031 |journal=Annual Review of Ecology and Systematics |volume=21 |pages=415 |doi=10.1146/annurev.es.21.110190.002151 |jstor=2097031 |issn=0066-4162 |quote=First, the effect may be direct, as, for example, the loss of one of the interacting partners in species-specific interactions may lead to the extinction of the other. |via=JSTOR |access-date=2021-06-20 |archive-date=2021-06-25 |archive-url=https://web.archive.org/web/20210625000352/https://www.jstor.org/stable/2097031 |url-status=live}} [103] => [104] => === Abiotic pollination === [105] => {{Main|Anemophily|Hydrophily}}{{Multiple image [106] => | image1 = Grassflower.svg [107] => | caption1 = A Grass flower with its long, thin filaments and large feathery stigma. [108] => | image2 = Enhalus acoroides fleur femelle.jpg [109] => | direction = vertical [110] => | caption2 = The female flower of ''Enhalus acoroides'', which is pollinated through a combination of Hyphydrogamy and Ephydrogamy. [111] => }} [112] => Flowers that use abiotic, or non-living, vectors use the [[wind]] or, much less commonly, [[water]], to move pollen from one flower to the next. In wind-dispersed ([[anemophilous]]) species, the tiny pollen grains are carried, sometimes many thousands of kilometres,{{Cite journal |last=Robledo-Arnuncio |first=Juan José |date=April 2011 |title=Wind pollination over mesoscale distances: an investigation with Scots pine |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.2010.03588.x |journal=New Phytologist |language=en |volume=190 |issue=1 |pages=222–233 |doi=10.1111/j.1469-8137.2010.03588.x |pmid=21175640 |issn=0028-646X}} by the wind to other flowers. Common examples include the [[Poaceae|grasses]], [[birch trees]], along with many other species in the order ''[[Fagales]]'',{{Cite journal |last1=Sofiev |first1=M. |last2=Siljamo |first2=P. |last3=Ranta |first3=H. |last4=Linkosalo |first4=T. |last5=Jaeger |first5=S. |last6=Rasmussen |first6=A. |last7=Rantio-Lehtimaki |first7=A. |last8=Severova |first8=E. |last9=Kukkonen |first9=J. |date=2013-01-01 |title=A numerical model of birch pollen emission and dispersion in the atmosphere. Description of the emission module |url=https://doi.org/10.1007/s00484-012-0532-z |journal=International Journal of Biometeorology |language=en |volume=57 |issue=1 |pages=45–58 |doi=10.1007/s00484-012-0532-z |issn=1432-1254 |pmc=3527742 |pmid=22410824 |bibcode=2013IJBm...57...45S |access-date=2021-06-15 |archive-date=2022-02-21 |archive-url=https://web.archive.org/web/20220221171449/https://link.springer.com/article/10.1007/s00484-012-0532-z |url-status=live}} [[ragweed]]s, and many [[Cyperaceae|sedges]]. They have no need to attract pollinators and therefore tend not to grow large, showy, or colorful flowers, and do not have nectaries, nor a noticeable scent. Because of this, plants typically have many thousands of tiny flowers which have comparatively large, feathery stigmas; to increase the chance of pollen being received.{{Sfn|D. Mauseth|2016|p=241}} Whereas the pollen of entomophilous flowers is usually large, sticky, and rich in [[protein]] (to act as a "reward" for pollinators), anemophilous flower pollen is typically small-grained, very light, smooth, and of little nutritional value to [[insect]]s.{{Sfn|Knuth|Müller|Ainsworth Davis|1906|pp=68–72}}{{Cite journal |date=2012-02-01 |title=Evaluation of the nutritive value of maize for honey bees |url=https://www.sciencedirect.com/science/article/abs/pii/S0022191011003374 |journal=Journal of Insect Physiology |language=en |volume=58 |issue=2 |pages=278–285 |doi=10.1016/j.jinsphys.2011.12.001 |issn=0022-1910 |last1=Höcherl |first1=Nicole |last2=Siede |first2=Reinhold |last3=Illies |first3=Ingrid |last4=Gätschenberger |first4=Heike |last5=Tautz |first5=Jürgen |pmid=22172382 |access-date=2021-06-20 |archive-date=2021-06-24 |archive-url=https://web.archive.org/web/20210624202156/https://www.sciencedirect.com/science/article/abs/pii/S0022191011003374 |url-status=live}} In order for the wind to effectively pick up and transport the pollen, the flowers typically have anthers loosely attached to the end of long thin filaments, or pollen forms around a [[catkin]] which moves in the wind. Rarer forms of this involve individual flowers being moveable by the wind ([[Pendulous]]), or even less commonly; the anthers exploding to release the pollen into the wind.{{Sfn|Knuth|Müller|Ainsworth Davis|1906|pp=68–72}} [113] => [114] => Pollination through water ([[hydrophily]]) is a much rarer method, occurring in only around 2% of abiotically pollinated flowers. Common examples of this include ''Calitriche autumnalis'', ''[[Vallisneria spiralis]]'' and some [[Seagrass|sea-grasses]]. One characteristic which most species in this group share is a lack of an [[exine]], or protective layer, around the pollen grain.{{Sfn|Walker|2020|p=51}} Paul Knuth identified two types of hydrophilous pollination in 1906 and Ernst Schwarzenbach added a third in 1944. Knuth named his two groups 'Hyphydrogamy' and the more common 'Ephydrogamy.'{{Sfn|Knuth|Müller|Ainsworth Davis|1906|pp=68 – 69}} In hyphydrogamy pollination occurs below the surface of the water and so the pollen grains are typically negatively [[buoyant]]. For marine plants that exhibit this method the stigmas are usually stiff, while freshwater species have small and feathery stigmas.{{Cite journal |last=Cox |first=Paul Alan |date=1988-11-01 |title=Hydrophilous pollination |url=https://www.annualreviews.org/doi/10.1146/annurev.es.19.110188.001401 |journal=Annual Review of Ecology and Systematics |volume=19 |issue=1 |pages=261–279 |doi=10.1146/annurev.es.19.110188.001401 |issn=0066-4162 |access-date=2021-06-20 |archive-date=2021-06-24 |archive-url=https://web.archive.org/web/20210624204105/https://www.annualreviews.org/doi/10.1146/annurev.es.19.110188.001401 |url-status=live}} In ephydrogamy pollination occurs on the surface of the water and so the pollen has a low density to enable floating, though many also use rafts, and are [[Hydrophobe|hydrophobic]]. Marine flowers have floating thread-like stigmas and may have adaptations for the tide, while freshwater species create indentations in the water. The third category, set out by Schwarzenbach, is those flowers which transport pollen above the water through conveyance. This ranges from floating plants, ([[Lemnoideae]]), to [[staminate]] flowers (''[[Vallisneria]]''). Most species in this group have dry, spherical pollen which sometimes forms into larger masses, and female flowers which form depressions in the water; the method of transport varies. [115] => [116] => === Mechanisms === [117] => Flowers can be pollinated by two mechanisms; cross-pollination and self-pollination. No mechanism is indisputably better than the other as they each have their advantages and disadvantages. Plants use one or both of these mechanisms depending on their [[habitat]] and [[ecological niche]].{{Sfn|Walker|2020|p=36–37}} [118] => [119] => ==== Cross-pollination ==== [120] => Cross-pollination is the pollination of the carpel by pollen from a different plant of the same species. Because the genetic make-up of the sperm contained within the pollen from the other plant is different, their combination will result in a new, genetically distinct, plant, through the process of [[sexual reproduction]]. Since each new plant is genetically distinct, the different plants show [[Genetic variation|variation]] in their physiological and structural adaptations and so the [[population]] as a whole is better prepared for an adverse occurrence in the environment. Cross-pollination, therefore, increases the survival of the species and is usually preferred by flowers for this reason.{{Sfn|D. Mauseth|2016|pp=|p=238}}{{Sfn|D. Mauseth|2016|p=222}} [121] => [122] => The principal adaptive function of flowers is the promotion of cross-pollination or outcrossing, a process that allows the masking of deleterious mutations in the genome of progeny. The masking effect of outcrossing sexual reproduction is known as “genetic complementation”.Bernstein H, Byerly HC, Hopf FA, Michod RE. Genetic damage, mutation, and the evolution of sex. Science. 1985 Sep 20;229(4719):1277-81. doi: 10.1126/science.3898363. PMID: 3898363 This beneficial effect of outcrossing on progeny is also recognized as hybrid vigor or heterosis. Once outcrossing is established due to the benefits of genetic complementation, subsequent switching to inbreeding becomes disadvantageous because it allows expression of the previously masked deleterious recessive mutations, usually referred to as inbreeding depression. Charles Darwin in his 1889 book The Effects of Cross and Self-Fertilization in the Vegetable KingdomDarwin, C. R. 1876. The effects of cross and self fertilisation in the vegetable kingdom. London: John Murray". darwin-online.org.uk at the beginning of chapter XII noted “The first and most important of the conclusions which may be drawn from the observations given in this volume, is that generally cross-fertilisation is beneficial and self-fertilisation often injurious, at least with the plants on which I experimented.” [123] => [124] => ==== Self-pollination ==== [125] => [[File:Clianthus puniceus (Kaka Beak) flowers.jpg|thumb|''Clianthus puniceus'', the Kaka Beak.]] [126] => Self-pollination is the pollination of the carpel of a flower by pollen from either the same flower or another flower on the same plant,{{Sfn|D. Mauseth|2016|p=238}} leading to the creation of a genetic clone through [[asexual reproduction]]. This increases the reliability of producing seeds, the rate at which they can be produced, and lowers the amount energy needed.{{Sfn|Walker|2020|p=42}} But, most importantly, it limits [[genetic variation]]. In addition, self-pollination causes [[inbreeding depression]], due largely to the expression of recessive deleterious [[mutation]]s.{{Cite journal |last1=Charlesworth |first1=Deborah |last2=Willis |first2=John H. |date=November 2009 |title=The genetics of inbreeding depression |url=https://www.nature.com/articles/nrg2664 |journal=Nature Reviews Genetics |language=en |volume=10 |issue=11 |pages=783–796 |doi=10.1038/nrg2664 |issn=1471-0056}}{{Citation |last1=Bernstein |first1=H. |title=The Molecular Basis of the Evolution of Sex |date=1987 |work=Advances in Genetics |volume=24 |pages=323–370 |url=https://linkinghub.elsevier.com/retrieve/pii/S0065266008600127 |access-date= |publisher=Elsevier |language=en |doi=10.1016/s0065-2660(08)60012-7 |isbn=978-0-12-017624-3 |last2=Hopf |first2=F.A. |last3=Michod |first3=R.E.}} [127] => [128] => The extreme case of self-fertilization, when the ovule is fertilized by pollen from the same flower or plant, occurs in flowers that always self-fertilize, such as many [[dandelion]]s.{{Cite journal |last1=McPeek |first1=Tamara M. |last2=Wang |first2=Xianzhong |date=2007 |title=Reproduction of Dandelion (Taraxacum officinale) in a Higher CO2 Environment |url=https://www.jstor.org/stable/4539580 |journal=Weed Science |volume=55 |issue=4 |pages=334 |doi=10.1614/WS-07-021 |jstor=4539580 |s2cid=86250272 |issn=0043-1745 |via=[[JSTOR]] |access-date=2021-06-20 |archive-date=2021-06-25 |archive-url=https://web.archive.org/web/20210625000419/https://www.jstor.org/stable/4539580 |url-status=live}} Some flowers are self-pollinated and have flowers that never open or are self-pollinated before the flowers open; these flowers are called [[Cleistogamy|cleistogamous]]; many species in the genus [[Viola (plant)|''Viola'']] exhibit this, for example.{{Cite journal |last1=Gilmartin |first1=A. J. |last2=Brown |first2=Gregory K. |date=1985 |title=Cleistogamy in Tillandsia capillaris (Bromeliaceae) |url=https://www.jstor.org/stable/2388227 |journal=Biotropica |volume=17 |issue=3 |pages=256 |doi=10.2307/2388227 |jstor=2388227 |issn=0006-3606 |access-date=2021-06-20 |archive-date=2021-06-25 |archive-url=https://web.archive.org/web/20210625030110/https://www.jstor.org/stable/2388227 |url-status=live}} [129] => [130] => Conversely, many species of plants have ways of preventing self-pollination and hence, 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-incompatible.{{Sfn|D. Mauseth|2016|p=239}}{{Sfn|Walker|2020|p=34}} In ''[[Clianthus puniceus]]'', (pictured), self-pollination is used strategically as an "insurance policy." When a pollinator, in this case a bird, visits ''C. puniceus'' it rubs off the stigmatic covering and allows for pollen from the bird to enter the stigma. If no pollinators visit, however, then the stigmatic covering falls off naturally to allow for the flower's own anthers to pollinate the flower through self-pollination.{{Sfn|Walker|2020|p=42}} [131] => [132] => === Allergies === [133] => {{Main|Pollen allergy}} [134] => Pollen is a large contributor to [[asthma]] and other [[Respiratory allergy|respiratory allergies]] which combined affect between 10 and 50% of people worldwide. This number appears to be growing, as the temperature increases due to [[climate change]] mean that plants are producing more pollen{{Citation needed|date=September 2022}}, which is also more allergenic. Pollen is difficult to avoid, however, because of its small size and prevalence in the natural environment. Most of the pollen which causes allergies is that produced by wind-dispersed pollinators such as the [[Poaceae|grasses]], [[birch trees]], [[oak]] trees, and [[ragweed]]s; the allergens in pollen are proteins which are thought to be necessary in the process of pollination.{{Cite journal |last1=Chen |first1=Miaolin |last2=Xu |first2=Jie |last3=Devis |first3=Deborah |last4=Shi |first4=Jianxin |last5=Ren |first5=Kang |last6=Searle |first6=Iain |last7=Zhang |first7=Dabing |date=2016 |title=Origin and Functional Prediction of Pollen Allergens in Plants |journal=Plant Physiology |language=en |volume=172 |issue=1 |pages=341–357 |doi=10.1104/pp.16.00625 |issn=0032-0889 |pmc=5074609 |pmid=27436829}}{{Cite journal |last1=Constible |first1=Juanita |last2=Sandro |first2=Luke |last3=Lee |first3=Richard E. |date=2008 |title=Ah-choo! Increased Risk of Pollen Allergies in the Northern Hemisphere |url=https://www.jstor.org/stable/42992782 |journal=Journal of College Science Teaching |volume=37 |issue=4 |pages=82–89 |jstor=42992782 |issn=0047-231X |access-date=2021-06-20 |archive-date=2021-06-25 |archive-url=https://web.archive.org/web/20210625000032/https://www.jstor.org/stable/42992782 |url-status=live}} [135] => [136] => == Fertilization == [137] => {{Main|Fertilization|Double fertilization}} [138] => [[File:Sex (electronic resource) (1914) (14590686978).jpg|thumb|216x216px|A floral diagram, with the pollen tube labelled ''PG'']] [139] => [[Fertilisation|Fertilization]], also called ''Synagmy,'' occurs following pollination, which is the movement of pollen from the stamen to the carpel. It encompasses both [[plasmogamy]], the fusion of the [[protoplast]]s, and [[karyogamy]], the fusion of the [[Cell nucleus|nuclei]]. When pollen lands on the stigma of the flower it begins creating a [[pollen tube]] which runs down through the style and into the ovary. After penetrating the centre-most part of the ovary it enters the egg apparatus and into one [[synergid]]. At this point the end of the pollen tube bursts and releases the two sperm cells, one of which makes its way to an egg, while also losing its [[cell membrane]] and much of its [[protoplasm]]. The sperm's nucleus then fuses with the egg's nucleus, resulting in the formation of a [[zygote]], a [[diploid]] (two copies of each [[chromosome]]) cell.{{Sfn|D. Mauseth|2016|p=234}} [140] => [141] => Whereas in fertilization only plasmogamy, or the fusion of the whole sex cells, results, in Angiosperms (flowering plants) a process known as double fertilization, which involves both karyogamy and plasmogamy, occurs. In double fertilization the second sperm cell subsequently also enters the synergid and fuses with the two polar nuclei of the central cell. Since all three nuclei are [[haploid]], they result in a large [[endosperm]] nucleus which is [[triploid]].{{Sfn|D. Mauseth|2016|p=234}} [142] => [143] => == Seed development == [144] => {{Main|Seed development}} [145] => [146] => [[File:Autumn Red peaches.jpg|thumb|The fruit of a peach with the seed or stone inside.]] [147] => Following the formation of zygote it begins to grow through nuclear and cellular divisions, called [[mitosis]], eventually becoming a small group of cells. One section of it becomes the [[embryo]], while the other becomes the suspensor; a structure which forces the embryo into the [[endosperm]] and is later undetectable. Two small [[Primordium|primordia]] also form at this time, that later become the [[cotyledon]], which is used as an energy store. Plants which grow out one of these primordia are called [[monocotyledon]]s, while those that grow out two are [[dicotyledon]]s. The next stage is called the Torpedo stage and involves the growth of several key structures, including: the [[radicle]] (embryotic root), the [[epicotyl]] (embryotic stem), and the [[hypocotyl]], (the root/shoot junction). In the final step [[vascular tissue]] develops around the seed.{{Sfn|D. Mauseth|2016|pp=235–237}} [148] => [149] => == Fruit development == [150] => {{Main|Fruit#Development}} [151] => The ovary, inside which the seed is forming from the ovule, grows into a [[fruit]]. All the other main floral parts die during this development, including: the style, stigma, sepals, stamens, and petals. The fruit contains three structures: the [[exocarp]], or outer layer, the [[mesocarp]], or the fleshy part, and the [[endocarp]], or innermost layer, while the fruit wall is called the [[pericarp]]. The size, shape, toughness, and thickness varies among different fruit. This is because it is directly connected to the method of seed dispersal; that being the purpose of fruit - to encourage or enable the seed's dispersal and protect the seed while doing so.{{Sfn|D. Mauseth|2016|pp=235–237}} [152] => [153] => ==Seed dispersal== [154] => {{main|Biological dispersal|Seed dispersal}}{{Multiple image [155] => | image1 = {{As written|Kereru}} (New Zealand Wood Pigeon).jpg [156] => | caption1 = The kererū, ''[[Hemiphaga novaeseelandiae]]'', is an important disperser of seeds in New Zealand.{{Cite journal |last1=Wyman |first1=Tarryn |last2=Kelly |first2=Dave |date=2017 |title=Quantifying seed dispersal by birds and possums in a lowland New Zealand forest |url=http://newzealandecology.org/nzje/3286 |journal=New Zealand Journal of Ecology |volume=41 |issue=1 |doi=10.20417/nzjecol.41.4 |doi-access=free |access-date=2021-07-01 |archive-date=2021-06-30 |archive-url=https://web.archive.org/web/20210630133448/https://newzealandecology.org/nzje/3286 |url-status=live}} [157] => | image2 = This seed of a maple seed runs as a helicopter.jpg [158] => | caption2 = A [[Samara (fruit)|samara]] from a [[maple tree]] with its distinctive "wings."{{Cite journal |last1=Sipe |first1=Timothy W. |last2=Linnerooth |first2=Amy R. |date=1995 |title=Intraspecific Variation in Samara Morphology and Flight Behavior in Acer saccharinum (Aceraceae) |url=https://www.jstor.org/stable/2445868 |journal=American Journal of Botany |volume=82 |issue=11 |pages=1412–1419 |doi=10.2307/2445868 |jstor=2445868 |issn=0002-9122 |access-date=2021-07-01 |archive-date=2021-07-09 |archive-url=https://web.archive.org/web/20210709181608/https://www.jstor.org/stable/2445868 |url-status=live}} [159] => | direction = horizontal [160] => | image3 = Acaena novae-zelandiae1.jpg [161] => | caption3 = ''[[Acaena novae-zelandiae]]'' uses ''Epizoochory'' to disperse its seeds.{{Cite journal |date=2009-10-01 |title=Testing the capacity of clothing to act as a vector for non-native seed in protected areas |url=https://www.sciencedirect.com/science/article/pii/S0301479709002631 |journal=Journal of Environmental Management |language=en |volume=91 |issue=1 |pages=168–179 |doi=10.1016/j.jenvman.2009.08.002 |issn=0301-4797 |hdl=10072/29656 |hdl-access=free |last1=Mount |first1=Ann |last2=Pickering |first2=Catherine Marina |pmid=19717222 |access-date=2021-07-01 |archive-date=2021-06-29 |archive-url=https://web.archive.org/web/20210629022407/https://www.sciencedirect.com/science/article/pii/S0301479709002631 |url-status=live}} [162] => }} [163] => Following the pollination of a flower, fertilization, and finally the development of a seed and fruit, a mechanism is typically used to disperse the fruit away from the plant.{{Sfn|D. Mauseth|2016|p=248}} In Angiosperms (flowering plants) seeds are dispersed away from the plant so as to not force competition between the mother and the daughter plants,{{cite journal |name-list-style=amp |vauthors=Bowler DE, Benton TG |date=May 2005 |title=Causes and consequences of animal dispersal strategies: relating individual behaviour to spatial dynamics |journal=Biological Reviews of the Cambridge Philosophical Society |volume=80 |issue=2 |pages=205–25 |doi=10.1017/S1464793104006645 |pmid=15921049 |s2cid=39351147}} as well as to enable the colonisation of new areas. They are often divided into two categories, though many plants fall in between or in one or more of these:{{Sfn|Pijl|1972|p=71}} [164] => [165] => === Allochory === [166] => In allochory, plants use an external [[wikt:vector|vector]], or carrier, to transport their seeds away from them. These can be either [[wikt:biotic|biotic]] (living), such as by birds and ants, or [[wikt:abiotic|abiotic]] (non-living), such as by the wind or water.{{Sfn|Pijl|1972|p=71}}{{Cite book |last=Forget |first=Pierre-Michel |url=https://www.worldcat.org/oclc/54803650 |title=Seed fate : predation, dispersal, and seedling establishment |date=2005 |publisher=CABI Pub |isbn=0-85199-806-2 |location=Wallingford, Oxfordshire, UK |pages=21 |oclc=54803650 |quote="Seeds on plants can be dispersed via a variety of primary dispersal mechanisms, including abiotic factors, like wind or ballistic projection, or biotic factors, like fruit-eating birds." |access-date=2021-07-01 |archive-date=2022-02-21 |archive-url=https://web.archive.org/web/20220221171457/https://www.worldcat.org/title/seed-fate-predation-dispersal-and-seedling-establishment/oclc/54803650 |url-status=live}}'''' [167] => [168] => ==== Biotic vectors ==== [169] => {{Main|Seed dispersal#Animals: epi- and endozoochory}} [170] => Many plants use biotic vectors to disperse their seeds away from them. This method falls under the umbrella term ''Zoochory,'' while ''[[Endozoochory]],'' also known as ''fruigivory,'' refers specifically to plants adapted to grow fruit in order to attract animals to eat them. Once eaten they go through typically go through animal's digestive system and are dispersed away from the plant.{{Cite journal |last1=Norsworthy |first1=Jason K. |last2=Griffith |first2=Griff |last3=Griffin |first3=Terry |last4=Bagavathiannan |first4=Muthukumar |last5=Gbur |first5=Edward E. |date=2014 |title=In-Field Movement of Glyphosate-Resistant Palmer Amaranth (Amaranthus palmen) and Its Impact on Cotton Lint Yield: Evidence Supporting a Zero-Threshold Strategy |url=https://www.jstor.org/stable/43700653 |journal=Weed Science |volume=62 |issue=2 |pages=237–249 |doi=10.1614/WS-D-13-00145.1 |jstor=43700653 |s2cid=86013249 |issn=0043-1745 |quote=Wind and water are common abiotic seed dispersal mechanisms, but there are several biotic dispersal mechanisms, such as movement via animals by adhesion (epizoochory) or ingestion (endozoochory), and even movement resulting from human activities (anthropochory). |via=[[JSTOR]] |access-date=2021-07-01 |archive-date=2021-07-09 |archive-url=https://web.archive.org/web/20210709205248/https://www.jstor.org/stable/43700653 |url-status=live}} Some seeds are specially adapted either to last in the [[gizzard]] of animals or even to germinate better after passing through them.{{Sfn|D. Mauseth|2016|pp=244–247}}{{Cite journal |last1=Traveset |first1=A. |last2=Riera |first2=N. |last3=Mas |first3=R. E. |date=2001 |title=Passage through bird guts causes interspecific differences in seed germination characteristics |url=https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1046/j.0269-8463.2001.00561.x |journal=Functional Ecology |language=en |volume=15 |issue=5 |pages=669–675 |doi=10.1046/j.0269-8463.2001.00561.x |issn=1365-2435 |quote=Many studies show that germination is more successful after seeds pass through the digestive tract of frugivores |access-date=2021-07-01 |archive-date=2021-07-09 |archive-url=https://web.archive.org/web/20210709182027/https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1046/j.0269-8463.2001.00561.x |url-status=live}} They can be eaten by birds (''ornithochory)'', bats (''chiropterochory)'', [[rodent]]s, primates, ants (''[[myrmecochory]]''),{{Cite journal |date=2010-02-20 |title=Convergent evolution of seed dispersal by ants, and phylogeny and biogeography in flowering plants: A global survey |url=https://www.sciencedirect.com/science/article/abs/pii/S1433831909000365 |journal=Perspectives in Plant Ecology, Evolution and Systematics |language=en |volume=12 |issue=1 |pages=43–55 |doi=10.1016/j.ppees.2009.08.001 |issn=1433-8319 |last1=Lengyel |first1=Szabolcs |last2=Gove |first2=Aaron D. |last3=Latimer |first3=Andrew M. |last4=Majer |first4=Jonathan D. |last5=Dunn |first5=Robert R. |access-date=2021-07-01 |archive-date=2021-07-02 |archive-url=https://web.archive.org/web/20210702154118/https://www.sciencedirect.com/science/article/abs/pii/S1433831909000365 |url-status=live}} non-bird sauropsids (''saurochory)'', mammals in general ''(mammaliochory)'',{{Sfn|D. Mauseth|2016|pp=244–247}} and even [[fish]].{{Cite journal |last1=Hämäläinen |first1=Anni |last2=Broadley |first2=Kate |last3=Droghini |first3=Amanda |last4=Haines |first4=Jessica A. |last5=Lamb |first5=Clayton T. |last6=Boutin |first6=Stan |last7=Gilbert |first7=Sophie |date=2017 |title=The ecological significance of secondary seed dispersal by carnivores |journal=Ecosphere |language=en |volume=8 |issue=2 |pages=e01685 |doi=10.1002/ecs2.1685 |issn=2150-8925 |doi-access=free}} Typically their fruit are fleshy, have a high nutritional value, and may have chemical attractants as an additional "reward" for dispersers. This is reflected [[Morphology (biology)|morphologically]] in the presence of more [[Pulp (fruit)|pulp]], an [[aril]], and sometimes an [[elaiosome]] (primarily for ants), which are other fleshy structures.''{{cite journal |author1=Howe, H. F. |author2=Smallwood J. |name-list-style=amp |year=1982 |title=Ecology of Seed Dispersal |url=http://artifex.org/~ecoreaders/lit/Howe1982.pdf |url-status=dead |journal=Annual Review of Ecology and Systematics |volume=13 |pages=201–228 |doi=10.1146/annurev.es.13.110182.001221 |archive-url=https://web.archive.org/web/20060513013354/http://artifex.org/~ecoreaders/lit/Howe1982.pdf |archive-date=2006-05-13}}'' [171] => [172] => ''[[Epizoochory]]'' occurs in plants whose seeds are adapted to cling on to animals and be dispersed that way, such as many species in the genus ''[[Acaena]].''{{Cite journal |last1=Symon |first1=D.E. |last2=Whalen |first2=M.A. |last3=Mackay |first3=D.A. |title=Diversity in Acaena (Rosaceae) in South Australia |date=2000 |url=https://www.jstor.org/stable/23874441 |journal=Journal of the Adelaide Botanic Garden |volume=19 |pages=55–73 |jstor=23874441 |issn=0313-4083 |via=[[JSTOR]] |access-date=2021-07-01 |archive-date=2021-06-28 |archive-url=https://web.archive.org/web/20210628225400/https://www.jstor.org/stable/23874441 |url-status=live}} Typically these plants seed's have hooks or a [[Viscosity|viscous]] surface to easier grip to animals, which include birds and animals with [[fur]]. Some plants use [[mimesis]], or imitation, to trick animals into dispersing the seeds and these often have specially adapted colors.''{{cite journal |last1=Vittoz |first1=Pascal |last2=Engler |first2=Robin |date=7 February 2008 |title=Seed dispersal distances: a typology based on dispersal modes and plant traits |url=http://doc.rero.ch/record/311682/files/35_2007_Article_797.pdf |journal=Botanica Helvetica |volume=117 |issue=2 |pages=109–124 |doi=10.1007/s00035-007-0797-8 |s2cid=2339616 |access-date=1 July 2021 |archive-date=27 June 2021 |archive-url=https://web.archive.org/web/20210627101700/http://doc.rero.ch/record/311682/files/35_2007_Article_797.pdf |url-status=live}}'' [173] => [174] => The final type of ''Zoochory'' is called ''[[Synzoochory]],'' which involves neither the digestion of the seeds, nor the unintentional carrying of the seed on the body, but the deliberate carrying of the seeds by the animals. This is usually in the mouth or [[beak]] of the animal (called ''Stomatochory''), which is what is used for many birds and all ants.{{Sfn|Pijl|1972|pp=24–25}} [175] => {{Multiple image [176] => | image1 = Usnea angulata 91023873.jpg [177] => | caption1 = The lichen ''[[Usnea angulata]]'', which uses ''hydrochory'', is a weed in [[New Zealand]].{{Cite journal |last1=Hyslop |first1=Jade |last2=Trowsdale |first2=Sam |date=2012 |title=A review of hydrochory (seed dispersal by water) with implications for riparian rehabilitation |url=https://www.jstor.org/stable/43945038 |journal=Journal of Hydrology (New Zealand) |volume=51 |issue=2 |pages=137–152 |jstor=43945038 |issn=0022-1708 |access-date=2021-07-01 |archive-date=2021-07-09 |archive-url=https://web.archive.org/web/20210709211826/https://www.jstor.org/stable/43945038 |url-status=live}} [178] => | image2 = Hura crepitans (fruit).jpg [179] => | direction = vertical [180] => | caption2 = ''[[Hura crepitans]]'' disperses its seeds ballistically and is hence commonly called the "dynamite tree."{{cite book |last=Feldkamp |first=Susan |title=Modern Biology |publisher=[[Holt, Rinehart, and Winston]] |year=2006 |location=United States |page=618}} [181] => | total_width = 185 [182] => }} [183] => [184] => ==== Abiotic vectors ==== [185] => {{Main|Anemochory|Seed dispersal#Water}} [186] => In abiotic dispersal plants use the vectors of the wind, water, or a mechanism of their own to transport their seeds away from them.'''' ''[[Anemochory]]'' involves using the wind as a vector to disperse plant's seeds. Because these seeds have to travel in the wind they are almost always small - sometimes even dust-like, have a high [[surface-area-to-volume ratio]], and are produced in a large number - sometimes up to a million. Plants such as [[tumbleweed]]s detach the entire shoot to let the seeds roll away with the wind. Another common adaptation are wings, plumes or balloon like structures that let the seeds stay in the air for longer and hence travel farther. [187] => [188] => In ''[[Hydrochory]]'' plants are adapted to disperse their seeds through bodies of water and so typically are buoyant and have a low [[relative density]] with regards to the water. Commonly seeds are adapted morphologically with hydrophobic surfaces, small size, hairs, slime, [[oil]], and sometimes air spaces within the seeds.'''' These plants fall into three categories: ones where seeds are dispersed on the surface of water currents, under the surface of water currents, and by rain landing on a plant. [189] => [190] => === Autochory === [191] => {{Main|Autochory}} [192] => In [[autochory]], plants create their own vectors to transport the seeds away from them. Adaptations for this usually involve the fruits exploding and forcing the seeds away [[Ballistics|ballistically]], such as in ''[[Hura crepitans]],'' or sometimes in the creation of creeping [[Diaspore (botany)|diaspores]].'''' Because of the relatively small distances that these methods can disperse their seeds, they are often paired with an external vector.'''' [193] => [194] => == Evolution == [195] => {{Further|Evolutionary history of plants#Flowers{{!}}Evolution of flowers|Floral biology}} [196] => While land plants have existed for about 425 million years, the first ones [[plant sexuality|reproduced]] by a simple adaptation of their aquatic counterparts: [[spore]]s. In the sea, plants—and some animals—can simply scatter out genetic [[Cloning|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 [[conifer]]s. [197] => [[File:Archaefructus liaoningensis.jpg|thumb|left|''[[Archaefructus]] liaoningensis'', one of the earliest known flowering plants]] [198] => [199] => Several groups of extinct [[gymnosperm]]s, particularly [[seed fern]]s, 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]]. [200] => [201] => 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.{{cite web |url=https://www.pbs.org/wgbh/nova/flower/anatomy.html |title=Flowers Modern & Ancient |first=Susan K. |last=Lewis |date=April 17, 2007 |publisher=[[PBS Online]] |access-date=2010-08-30 |url-status=live |archive-url=https://web.archive.org/web/20090907084221/http://www.pbs.org/wgbh/nova/flower/anatomy.html |archive-date=September 7, 2009}}{{cite episode |transcript=First Flower |transcript-url=https://www.pbs.org/wgbh/nova/transcripts/3405_flower.html |series=NOVA |date=2007-04-17 |network=PBS |station=WGBH}} 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.{{Cite news |url=https://www.theguardian.com/science/2015/aug/17/fossilised-remains-worlds-oldest-flower-discovered-cretaceous |title=Fossilised remains of world's oldest flower discovered in Spain |journal=The Guardian |date=Aug 17, 2015 |url-status=live |archive-url=https://web.archive.org/web/20170303051550/https://www.theguardian.com/science/2015/aug/17/fossilised-remains-worlds-oldest-flower-discovered-cretaceous |archive-date=2017-03-03 |last1=Thomson |first1=Helen}} In 2018, scientists reported that the earliest flowers began about 180 million years ago.{{cite news |author=Chinese Academy of Sciences |title=Flowers originated 50 million years earlier than previously thought |url=https://www.eurekalert.org/pub_releases/2018-12/caos-fo5121818.php |date=18 December 2018 |work=[[EurekAlert!]] |access-date=18 December 2018 |author-link=Chinese Academy of Sciences |archive-date=18 December 2018 |archive-url=https://web.archive.org/web/20181218172339/https://www.eurekalert.org/pub_releases/2018-12/caos-fo5121818.php |url-status=live}} [202] => [203] => [[File:Amborella trichopoda (3065968016) fragment.jpg|thumb|left|[[Amborella|''Amborella trichopoda'']] may have characteristic features of the earliest flowering plants]] [204] => Recent [[DNA]] analysis ([[molecular systematics]]){{Cite journal |title=Amborella not a "basal angiosperm"? Not so fast |journal=American Journal of Botany |volume=91 |issue=6 |pages=997–1001 |doi=10.3732/ajb.91.6.997 |pmid=21653455 |year=2004 |last1=Soltis |first1=Douglas E. |last2=Soltis |first2=Pamela S. |doi-access=free}} shows that [[Amborella|''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.{{cite web |url=http://www.eurekalert.org/pub_releases/2006-05/uoca-spp051506.php |title=South Pacific plant may be missing link in evolution of flowering plants |publisher=Eurekalert.org |date=2006-05-17 |access-date=2010-08-30 |url-status=live |archive-url=https://web.archive.org/web/20110514101042/http://www.eurekalert.org/pub_releases/2006-05/uoca-spp051506.php |archive-date=2011-05-14}} [205] => [206] => Besides the hard proof of flowers in or shortly before the [[Cretaceous]],{{cite news |last=Gabbott |first=Sarah |title=Did the first flower look like this? |url=https://www.bbc.com/news/science-environment-40780491 |date=1 August 2017 |work=[[BBC News]] |access-date=1 August 2017 |url-status=live |archive-url=https://web.archive.org/web/20170801235428/http://www.bbc.com/news/science-environment-40780491 |archive-date=1 August 2017}}{{cite journal |author=Sauquet, Hervé |display-authors=etal |title=The ancestral flower of angiosperms and its early diversification |date=1 August 2017 |journal=[[Nature Communications]] |volume=8 |pages=16047 |doi=10.1038/ncomms16047 |pmid=28763051 |pmc=5543309 |bibcode=2017NatCo...816047S}} 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 [[gigantopterid]]s,{{cite web |url=https://www.sciencedaily.com/releases/2001/04/010403071438.htm |title=Oily Fossils Provide Clues To The Evolution Of Flowers |publisher=Sciencedaily.com |date=2001-04-05 |access-date=2010-08-30 |url-status=live |archive-url=https://web.archive.org/web/20100819001553/http://www.sciencedaily.com/releases/2001/04/010403071438.htm |archive-date=2010-08-19}} 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 [[petrified wood|petrification]]. [207] => [208] => The similarity in [[leaf]] and [[Plant stem|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.{{cite web |url=http://unisci.com/stories/20012/0615015.htm |title=Age-Old Question On Evolution Of Flowers Answered |publisher=Unisci.com |date=2001-06-15 |access-date=2010-08-30 |url-status=live |archive-url=https://web.archive.org/web/20100610212816/http://www.unisci.com/stories/20012/0615015.htm |archive-date=2010-06-10}} 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 [[Plant reproductive morphology#Bisexual|bisexual]] (in plants, this means both male and female parts on the same flower), and to be dominated by the [[ovary (plants)|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". [209] => [210] => 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 wasp]]s 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. [211] => [212] => 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. [213] => [214] => While many such [[symbiotic relationship]]s 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. [215] => [216] => 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.{{Cite web |last=May 2005 |first=Robert Roy Britt 26 |date=2005-05-26 |title=Human Affection Altered Evolution of Flowers |url=https://www.livescience.com/295-human-affection-altered-evolution-flowers.html |access-date=2021-09-06 |website=livescience.com |language=en |archive-date=2021-09-06 |archive-url=https://web.archive.org/web/20210906031029/https://www.livescience.com/295-human-affection-altered-evolution-flowers.html |url-status=live}} [217] => [218] => == Colour == [219] => {{See also|Color garden}} [220] => [[File:Spectrum of Flowers(Rosa) en.pdf|thumb|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).]] [221] => Many flowering plants reflect as much [[light]] as possible within the range of visible [[wavelength]]s 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.{{citation needed|date=February 2023}} The color model used by human color reproduction technology ([[CMYK color model|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 [[Color wheel|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.{{citation needed|date=February 2023}} 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 (color theory)|saturation]] (the amount of ''white'' in the color). [222] => [223] => == Classical taxonomy == [224] => {{Main|Linnaean taxonomy|Plant taxonomy}} [225] => [226] => [[File:Carl von Linné (cropped).png|thumb|[[Carl Linnaeus]]'s method for classifying plants focused solely on the structure and nature of the flowers.{{Sfn|Sharma|2009|p=21}}|left|246x246px]] [227] => [228] => In [[plant taxonomy]], which is the study of the classification and identification of plants, the [[Morphology (biology)|morphology]] of plant's flowers are used extensively – and have been for thousands of years. Although the history of plant taxonomy extends back to at least around 300 [[Common Era|B.C.]] with the writings of [[Theophrastus]],{{Sfn|Sharma|2009|p=8}} the foundation of the modern science is based on works in the 18th and 19th centuries.{{Sfn|Sharma|2009|p=10}} [229] => [230] => [[Carl Linnaeus]] (1707–1778), was a Swedish botanist who spent most of his working life as a professor of natural history. His landmark 1757 book ''[[Species Plantarum]]'' lays out his system of classification as well as the concept of [[binomial nomenclature]], the latter of which is still used around the world today.{{Sfn|Sharma|2009|p=10}}{{NoteTag|His earlier works: ''[[Systema Naturae]]'' (1735) and ''[[Genera plantarum]]'' (1737) were also influential in the field.{{Sfn|Sharma|2009|p=21}}|name=Sharma 2009 21}} He identified 24 classes, based mainly on the number, length and union of the [[stamen]]s. The first ten classes follow the number of stamens directly (''Octandria'' have 8 stamens etc.),{{Sfn|Sharma|2009|p=21}} while class eleven has 11–20 stamens and classes twelve and thirteen have 20 stamens; differing only in their point of attachment. The next five classes deal with the length of the stamens and the final five with the nature of the reproductive capability of the plant; where the stamen grows; and if the flower is concealed or exists at all (such as in [[fern]]s). This method of classification, despite being artificial,{{Sfn|Sharma|2009|p=21}} was used extensively for the following seven decades, before being replaced by the system of another botanist.{{Sfn|Sharma|2009|p=22}} [231] => [232] => [[Antoine Laurent de Jussieu]] (1748–1836) was a French botanist whose 1787 work ''Genera plantarum: secundum ordines naturales disposita'' set out a new method for classifying plants; based instead on natural characteristics. Plants were divided by the number, if any, of [[cotyledon]]s, and the location of the stamens.{{Sfn|Sharma|2009|p=22}} The next most major system of classification came in the late 19th century from the botanists [[Joseph Dalton Hooker]] (1817–1911) and [[George Bentham]] (1800–1884). They built on the earlier works of de Jussieu and [[Augustin Pyramus de Candolle]] and devised a system which is still used in many of the world's [[Herbarium|herbaria]]. Plants were divided at the highest level by the number of cotyledons and the nature of the flowers, before falling into orders ([[Family (biology)|families]]), [[Genus|genera]], and [[species]]. This system of classification was published in their ''[[Bentham & Hooker system|Genera plantarum]]'' in three volumes between 1862 and 1883.{{Sfn|Sharma|2009|pp=24–27}} It is the most highly regarded and deemed the "best system of classification," in some settings.{{Sfn|Sharma|2009|p=11}} [233] => [234] => Following the development in scientific thought after Darwin's ''[[On the Origin of Species]]'', many botanists have used more [[Phylogenetics|phylogenetic]] methods and the use of [[DNA sequencing|genetic sequencing]], [[cytology]], and [[palynology]] has become increasingly common. Despite this, [[Morphology (biology)|morphological]] characteristics such as the nature of the flower and [[inflorescence]] still make up the bedrock of plant taxonomy.{{Sfn|Sharma|2009|p=11}}{{Sfn|Sharma|2009|p=96}} [235] => [236] => == Symbolism == [237] => [[File:Liliumbulbiferumflowertop.jpg|thumb|[[Lily|Lilies]] are often used to denote life or resurrection]] [238] => {{Main|Language of flowers}} [239] => Many flowers have important [[symbol]]ic meanings in Western culture.{{Cite web |url=https://flowermag.com/the-meanings-of-flowers/ |title=The Meanings of Flowers |date=2018-05-28 |website=Flower Magazine |language=en |access-date=2018-12-12 |archive-date=2020-07-31 |archive-url=https://web.archive.org/web/20200731205634/https://flowermag.com/the-meanings-of-flowers/ |url-status=live}} The practice of assigning meanings to flowers is known as [[floriography]]. Some of the more common examples include: [240] => * Red [[rose]]s are given as a symbol of love, beauty, and passion.{{cite web |last1=Audet |first1=Marye |title=Roses and Their Meaning |url=http://garden.lovetoknow.com/wiki/Roses_and_Their_Meaning |access-date=22 August 2014 |url-status=live |archive-url=https://web.archive.org/web/20140826114033/http://garden.lovetoknow.com/wiki/Roses_and_Their_Meaning |archive-date=26 August 2014}} [241] => * [[Poppy|Poppies]] are a symbol of consolation in time of death. In the United Kingdom, New Zealand, Australia and Canada, [[Remembrance poppy|red poppies]] are worn to commemorate soldiers who have died in times of war. [242] => * [[Iris (plant)|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. [243] => * [[Asteraceae|Daisies]] are a symbol of innocence. [244] => [245] => [[File:Ambrosius Bosschaert the Elder (Dutch - Flower Still Life - Google Art Project.jpg|thumb|left|Flowers are common subjects of [[still life]] paintings, such as this one by [[Ambrosius Bosschaert the Elder]]]] [246] => 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 [[Vincent van Gogh|Van Gogh]]'s [[sunflowers (series of paintings)|sunflowers]] series or [[Claude Monet|Monet]]'s water lilies. Flowers are also dried, freeze dried and pressed in order to create permanent, three-dimensional pieces of [[Floral design|floral art]]. [247] => [248] => Flowers within art are also representative of the [[female genitalia]],{{cite thesis |last1=Frownfelter |first1=Andrea |title=Flower Symbolism as Female Sexual Metaphor |url=http://commons.emich.edu/cgi/viewcontent.cgi?article=1210&context=honors |publisher=Eastern Michigan University |url-status=live |archive-url=https://web.archive.org/web/20140810175632/http://commons.emich.edu/cgi/viewcontent.cgi?article=1210&context=honors |archive-date=2014-08-10}} 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]]. [249] => [250] => The great variety of delicate and beautiful flowers has inspired the works of numerous poets, especially from the 18th–19th century [[Romantic poetry|Romantic]] era. Famous examples include [[William Wordsworth]]'s ''[[I Wandered Lonely as a Cloud]]'' and [[William Blake]]'s ''[[Ah! Sun-Flower]]''. [251] => [252] => Their symbolism in dreams has also been discussed, with possible interpretations including "blossoming potential".{{Cite book |last=Dee |first=Nerys |url=https://www.worldcat.org/oclc/33208041 |title=Your dreams & what they mean: how to understand the secret language of sleep |date=1995 |publisher=Thornsons |isbn=978-0-7225-3218-8 |location=London |pages=142 |language=English |oclc=33208041 |access-date=2021-06-15 |archive-date=2022-02-21 |archive-url=https://web.archive.org/web/20220221171506/https://www.worldcat.org/title/your-dreams-what-they-mean-how-to-understand-the-secret-language-of-sleep/oclc/33208041 |url-status=live}} [253] => [254] => The Roman goddess of flowers, gardens, and the season of Spring is [[Flora (goddess)|Flora]]. The Greek goddess of spring, flowers and nature is [[Chloris]]. [255] => [256] => 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 [[Sacred lotus in religious art|lotus flower]].{{cite web |url=http://www.bbc.co.uk/religion/religions/hinduism/deities/vishnu.shtml |title=Vishnu |publisher=Bbc.co.uk |date=2009-08-24 |access-date=2010-08-30 |url-status=live |archive-url=https://web.archive.org/web/20101028091134/http://www.bbc.co.uk/religion/religions/hinduism/deities/vishnu.shtml |archive-date=2010-10-28}} Apart from the association with Vishnu, the Hindu tradition also considers the lotus to have spiritual significance.{{cite web |url=http://www.hinduismtoday.com/archives/1999/7/1999-7-13.shtml |title=God's Favorite Flower |publisher=Hinduism Today |access-date=2010-08-30 |url-status=dead |archive-url=https://web.archive.org/web/20090413163953/http://www.hinduismtoday.com/archives/1999/7/1999-7-13.shtml |archive-date=2009-04-13}} For example, it figures in the Hindu stories of creation.{{cite web |url=http://www.theosociety.org/pasadena/sunrise/49-99-0/ge-mrook.htm |archive-url=https://web.archive.org/web/20170910161534/http://www.theosociety.org/pasadena/sunrise/49-99-0/ge-mrook.htm |archive-date=2017-09-10 |title=The Lotus |publisher=Theosociety.org |access-date=2010-08-30 |url-status=dead}} [257] => [258] => == Human use == [259] => {{more citations needed section|date=November 2018}} [260] => {{further|Plants in culture}} [261] => [262] => [[File:Ilmmuenster Kirche Altar.jpg|thumb|250px|[[Chancel flowers]], placed upon the [[altar]] of St. Arsatius's Church in [[Ilmmünster]] ]] [263] => [264] => History shows that flowers have been used by humans for thousands of years, to serve a variety of purposes. An early example of this is from about 4,500 years ago in [[Ancient Egypt]], where flowers would be used to decorate women's hair. Flowers have also inspired art time and time again, such as in [[Water Lilies (Monet series)|Monet's ''Water Lilies'']] or [[William Wordsworth|William Wordsworth's]] poem about [[Narcissus (plant)|daffodils]] entitled: "[[I Wandered Lonely as a Cloud]]".{{Cite book |last1=Fogden |first1=Michael |title=The Natural History of Flowers |last2=Fogden |first2=Patricia |publisher=Texas A&M University Press |year=2018 |isbn=978-1623496449 |pages=1}} [265] => [266] => [[File:CynhebrwngCochrane1901.jpg|thumb|Brazilian sailors pay floral tribute to British naval flag officer [[Thomas Cochrane, 10th Earl of Dundonald|Thomas Cochrane]] in [[Westminster Abbey]], 1901]] [267] => 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 [[odor|smell]]. Around the world, people use flowers to mark important events in their lives: [268] => * For new births or [[infant baptism|christenings]] [269] => * As a [[corsage]] or [[boutonniere]] worn at social functions or for holidays [270] => * As tokens of love or esteem [271] => * For wedding flowers for the bridal party, and as decorations for [[wedding venue]]s [272] => * As brightening decorations within the home [273] => * As a gift of remembrance for ''bon voyage'' parties, welcome-home parties, and "thinking of you" gifts [274] => * For [[funeral]] flowers and expressions of [[sympathy]] for the grieving [275] => * For worship. In [[Christianity]], [[chancel flowers]] often adorn churches.{{Cite book |last=Wilson |first=Adelaide B |url=https://www.worldcat.org/oclc/500430357 |title=Flowers for your church. |date=1967 |publisher=Barrows & Co. |location=Place of publication not identified |pages=26 |language=English |oclc=500430357 |access-date=2021-06-15 |archive-date=2021-06-28 |archive-url=https://web.archive.org/web/20210628193719/https://www.worldcat.org/title/flowers-for-your-church/oclc/500430357 |url-status=live}} In [[Hindu]] culture, adherents commonly bring flowers as a gift to [[temple]]s{{cite web |title=VISITING A HINDU TEMPLE; A BEGINNER'S GUIDE |url=https://www.hinduismtoday.com/modules/smartsection/item.php?itemid=818 |publisher=[[Hinduism Today]] |date=April 1991 |access-date=2018-11-27 |archive-date=2021-04-16 |archive-url=https://web.archive.org/web/20210416172944/https://www.hinduismtoday.com/modules/smartsection/item.php?itemid=818 |url-status=live}} [276] => [277] => [[File:Aikya Linga in Varanasi.jpg|thumb|upright|A woman spreading flowers over a [[lingam]] in a temple in [[Varanasi]]]] [278] => [[File:Various flowers from India, collected for worship of Hindu deities in morning.jpg|thumb|Flowers collected for worship of Hindu deities in morning, in [[West Bengal]].]] [279] => [280] => Flowers like [[jasmine]] have been used as a replacement for traditional tea in China for centuries. Most recently many other herbs and flowers used traditionally across the world are gaining importance to preapare a range of [[floral tea]].{{citation needed|date=January 2022}} [281] => [282] => People therefore grow flowers around their homes, dedicate parts of their living space to [[flower garden]]s, pick wildflowers, or buy [[Horticulture industry|commercially-grown]] flowers from [[florist]]s. Flower production and trade supports [[developing economies]] through their availability as a [[fair trade]] product.[[Fairtrade Foundation]], [https://www.fairtrade.org.uk/Farmers-and-Workers/Flowers/ Flower farmers and workers], accessed 23 March 2023 [283] => [284] => [[File:Tamperefloral.jpg|thumb|upright|View of the [[Tampere Central Square]] during the [[Tampere Floral Festival]] in July 2007.]] [285] => [286] => Flowers provide less food than other major plant parts ([[seed]]s, [[fruit]]s, [[root]]s, [[plant stem|stems]] and [[leaf|leaves]]), but still provide several important [[vegetable]]s and [[spice]]s. Flower vegetables include [[broccoli]], [[cauliflower]] and [[artichoke]]. The most expensive spice, [[saffron]], consists of dried stigmas of a [[crocus]]. Other flower spices are [[clove]]s and [[caper]]s. [[Hops]] flowers are used to flavor [[beer]]. [[Calendula|Marigold]] flowers are fed to [[chicken]]s 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 [[Sambucus|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 (fruit)|orange]] blossom honey, [[clover]] honey and [[Tupelo (tree)|tupelo]] honey. [287] => [288] => [[list of edible flowers|Hundreds of fresh flowers are edible]], but only few are widely marketed as food. They are often added to [[salad]]s as [[garnish (food)|garnishes]]. [[Squash blossom]]s are dipped in breadcrumbs and fried. Some [[edible flower]]s include [[nasturtium (common name)|nasturtium]], [[chrysanthemum]], [[carnation]], [[cattail]], [[Japanese honeysuckle]], [[chicory]], [[cornflower]], [[Canna (plant)|canna]], and [[sunflower]].{{cite news |last1=Wood |first1=Zoe |title=Blooming tasty – edible flowers are summer's hottest food trend |url=https://www.theguardian.com/lifeandstyle/2017/jun/30/blooming-tasty-edible-flowers-are-summers-hottest-food-trend |work=[[The Guardian]] |date=30 June 2017 |access-date=27 November 2018 |archive-date=27 November 2018 |archive-url=https://web.archive.org/web/20181127193545/https://www.theguardian.com/lifeandstyle/2017/jun/30/blooming-tasty-edible-flowers-are-summers-hottest-food-trend |url-status=live}} Edible flowers such as [[Asteraceae|daisy]], [[rose]], and [[viola (plant)|violet]] are sometimes candied.{{cite news |last1=Bradley |first1=Sue |title=How to crystallise flowers like the Victorians |url=https://www.telegraph.co.uk/gardening/gardenprojects/11590050/How-to-crystallise-flowers-like-the-Victorians.html |archive-url=https://ghostarchive.org/archive/20220111/https://www.telegraph.co.uk/gardening/gardenprojects/11590050/How-to-crystallise-flowers-like-the-Victorians.html |archive-date=2022-01-11 |url-access=subscription |url-status=live |work=[[The Daily Telegraph|The Telegraph]] |date=8 May 2015}}{{cbignore}} [289] => [290] => Flowers such as chrysanthemum, rose, jasmine, Japanese honeysuckle, and [[chamomile]], chosen for their fragrance and medicinal properties, are used as [[tisane]]s, either mixed with [[camellia sinensis|tea]] or on their own.{{cite news |last1=Wong |first1=James |title=Grow your own herbal teas |url=https://www.theguardian.com/lifeandstyle/2017/may/07/grow-your-own-herbal-teas |work=[[The Guardian]] |date=7 May 2017 |access-date=27 November 2018 |archive-date=27 November 2018 |archive-url=https://web.archive.org/web/20181127195123/https://www.theguardian.com/lifeandstyle/2017/may/07/grow-your-own-herbal-teas |url-status=live}} [291] => [292] => 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.{{cite news |title=Stone Age mourners 'placed flowers on graves' |url=https://www.telegraph.co.uk/news/science/11596312/Stone-Age-mourners-placed-flowers-on-graves.html |archive-url=https://ghostarchive.org/archive/20220111/https://www.telegraph.co.uk/news/science/11596312/Stone-Age-mourners-placed-flowers-on-graves.html |archive-date=2022-01-11 |url-access=subscription |url-status=live |work=[[The Daily Telegraph|The Telegraph]] |date=10 May 2015}}{{cbignore}} 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 Greece|ancient Greeks]], as recorded in [[Euripides]]'s play ''[[The Phoenician Women]]'', placed a crown of flowers on the head of the deceased;{{cite web |title=Burial Rites |url=http://www.hellenicaworld.com/Greece/Ancient/en/BurialRites.html |publisher=Hellenica World |access-date=28 November 2018 |archive-date=29 November 2018 |archive-url=https://web.archive.org/web/20181129054310/http://www.hellenicaworld.com/Greece/Ancient/en/BurialRites.html |url-status=live}} they also covered tombs with wreaths and flower petals. Flowers were widely used in [[ancient Egypt]]ian burials,{{cite book |last=Hays |first=Christopher B. |title=Death in the Iron Age II and in First Isaiah |url=https://books.google.com/books?id=IcpdmHW87EAC&pg=PA302 |year=2011 |publisher=Mohr Siebeck |isbn=978-3-16-150785-4 |page=302 |access-date=2018-11-28 |archive-date=2019-12-28 |archive-url=https://web.archive.org/web/20191228235720/https://books.google.com/books?id=IcpdmHW87EAC&pg=PA302 |url-status=live}} and the [[Mexico|Mexicans]] to this day use flowers prominently in their [[Day of the Dead]] celebrations{{cite book |first=Frances Ann |last=Day |title=Latina and Latino Voices in Literature |publisher=Greenwood |year=2003 |page=[https://archive.org/details/latinalatinovoic0000dayf/page/72 72] |isbn=978-0-313-32394-2 |url=https://archive.org/details/latinalatinovoic0000dayf/page/72}} in the same way that their [[Aztec]] ancestors did. [293] => [294] => {{wide image|15 Qian Xuan Eight Flowers National Palace Museum Beijing.JPG|1000px|''Eight Flowers'', a painting by artist [[Qian Xuan]], 13th century, [[Palace Museum]], Beijing.}} [295] => [296] => === Giving === [297] => [[File:Eastern Market Detroit flower.JPG|thumb|right|upright|Flower market – [[Detroit]]'s [[Eastern Market Historic District|Eastern Market]]]] [298] => The flower-giving tradition goes back to prehistoric times when flowers often had a medicinal and herbal attributes. Archaeologists found in several grave sites remnants of flower petals. Flowers were first used as sacrificial and burial objects. [[Ancient Egypt]]ians and later Greeks and Romans used flowers. In Egypt, burial objects from the time around 1540 BC{{Citation needed|date=April 2019}} were found, which depicted [[red poppy]], [[yellow Araun]], [[Centaurea cyanus|cornflower]] and [[Lilium|lilies]]. Records of flower giving appear in [[Chinese culture|Chinese writings]] and Egyptian hieroglyphics, as well as in [[Greek mythology|Greek]] and [[Roman mythology]]. The practice of giving a flower flourished in the Middle Ages when couples showed affection through flowers. [299] => [300] => The tradition of flower-giving exists in many forms. It is an important part of [[Russian culture]] and 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]].{{Cite web |url=http://www.flowersofthefieldlv.com/the-fascinating-tradition-of-giving-flowers/ |title=The Fascinating Tradition of Giving Flowers |last=By |date=2015-08-11 |website=Flowers of the Field Las Vegas |language=en |access-date=2019-03-15 |archive-date=2019-03-16 |archive-url=https://web.archive.org/web/20190316064821/http://www.flowersofthefieldlv.com/the-fascinating-tradition-of-giving-flowers/ |url-status=live}}{{Cite web |url=https://web.stanford.edu/group/ccr/ccrblog/2010/03/flowers_in_russia.html |title=The Cross-Cultural Rhetoric Blog: Flowers in Russia |website=web.stanford.edu |access-date=2019-03-15 |archive-date=2019-04-13 |archive-url=https://web.archive.org/web/20190413030650/http://web.stanford.edu/group/ccr/ccrblog/2010/03/flowers_in_russia.html |url-status=dead}}{{Cite web |url=http://kurochkaclothing.com/news/folk-art-in-russia-and-ukraine/ |title=Folk Art in Russia and Ukraine {{!}} News & Info |language=en-US |access-date=2019-03-15 |archive-date=2019-03-24 |archive-url=https://web.archive.org/web/20190324190043/http://kurochkaclothing.com/news/folk-art-in-russia-and-ukraine/ |url-status=live}} [301] => [302] => == See also == [303] => *[[Floral color change]] [304] => *[[Flower preservation]] [305] => * [[Garden]] [306] => * [[List of garden plants]] [307] => * [[Plant evolutionary developmental biology]] [308] => * [[Plant reproductive morphology]] [309] => * [[Sowing]] [310] => [311] => == Notes == [312] => {{NoteFoot}} [313] => [314] => == References == [315] => === Citations === [316] => {{Reflist}} [317] => [318] => === Sources === [319] => {{refbegin}} [320] => * {{Cite book |last1=De Craene |first1=Ronse |last2=P. |first2=Louis |url=http://dx.doi.org/10.1017/cbo9780511806711 |title=Floral Diagrams |date=2010 |publisher=Cambridge University Press |isbn=978-0-511-80671-1 |location=Cambridge |doi=10.1017/cbo9780511806711}} [321] => * {{cite book |last1=Knuth |first1=Paul |url=https://doi.org/10.5962/bhl.title.54973 |title=Handbook of flower pollination: based upon Hermann Müller's work 'The fertilisation of flowers by insects' |volume=1 |last2=Müller |first2=Hermann |last3=Ainsworth Davis |first3=J. R. |publisher=Clarendon Press |year=1906 |doi=10.5962/bhl.title.54973 |oclc=1841036 |access-date=2021-06-15 |archive-date=2022-02-21 |archive-url=https://web.archive.org/web/20220221171547/https://www.biodiversitylibrary.org/bibliography/54973 |url-status=live}} [322] => * {{cite book |last1=Fritsch |first1=Felix Eugene |url=http://archive.org/details/cu31924001698905 |title=An introduction to the structure and reproduction of plants |last2=Salisbury |first2=E. J. (Edward James) |year=1920 |location=London |publisher=G. Bell and Sons Ltd. |others=Cornell University Library}} [323] => *{{cite book |last=Walker |first=Timothy |title=Pollination: The Enduring Relationship Between Plant and Pollinator |publisher=[[Princeton University Press]] |year=2020 |isbn=978-0-691-20375-1}} [324] => *{{cite book |last=D. Mauseth |first=James |title=Botany: An Introduction to Plant Biology |publisher=Jones & Bartlett Learning |year=2016 |isbn=978-1-284-07753-7 |edition=6th}} [325] => *{{cite book |last=Pijl |first=L. van der |url=https://www.springer.com/gp/book/9783642961083 |title=Principles of Dispersal in Higher Plants |year=1972 |publisher=Springer-Verlag |isbn=978-3-642-96108-3 |edition=2nf |location=Berlin Heidelberg |language=en |access-date=2021-07-01 |archive-date=2021-07-09 |archive-url=https://web.archive.org/web/20210709181814/https://www.springer.com/gp/book/9783642961083 |url-status=live}} [326] => * {{cite book |last=Sharma |first=O. P. |title=Plant Taxonomy |publisher=[[McGraw Hill Education|Tata McGraw Hill Education Private Limited]] |year=2009 |isbn=978-0070141599 |edition=2nd |location=New Delhi, India}} [327] => {{refend}} [328] => [329] => == Further reading == [330] => * {{cite book |first=Stephen |last=Buchmann |year=2016 |isbn=978-1-4767-5553-3 |publisher=Scribner |title=The Reason for Flowers: Their History, Culture, Biology, and How They Change Our Lives}} [331] => * {{cite book |last=Esau |first=Katherine |date=1965 |title=Plant Anatomy |edition=2nd |publisher=John Wiley & Sons |location=New York |isbn=978-0-471-24455-4 |url-access=registration |url=https://archive.org/details/plantanatomy00esau_0}} [332] => * {{cite book |last=Greyson |first=R.I. |date=1994 |title=The Development of Flowers |publisher=Oxford University Press |isbn=978-0-19-506688-3 |url-access=registration |url=https://archive.org/details/developmentofflo0000grey}} [333] => * {{cite book |last1=Leins |first1=P. |name-list-style=amp |last2=Erbar |first2=C. |date=2010 |title=Flower and Fruit |publisher=Schweizerbart Science Publishers |location=Stuttgart |isbn=978-3-510-65261-7}} [334] => * {{cite book |last=Sattler |first=R. |date=1973 |title=Organogenesis of Flowers. A Photographic Text-Atlas |publisher=University of Toronto Press |isbn=978-0-8020-1864-9}} [335] => [336] => == External links == [337] => {{Wiktionary|flower}} [338] => {{Commons and category|Flowers|Flowers}} [339] => * {{wikiquote-inline|Flowers}} [340] => * [https://web.archive.org/web/20090510230926/http://wildflower.utexas.edu/ Native Plant Information Network] [341] => [342] => {{Botany}} [343] => {{Authority control}} [344] => [345] => [[Category:Flowers| ]] [346] => [[Category:Plant morphology]] [347] => [[Category:Plant reproductive system]] [348] => [[Category:Plant sexuality]] [349] => [[Category:Pollination]] [350] => [[Category:Periodic phenomena]] [351] => [[Category:Symbols]] [] => )
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Flower

A flower is the reproductive structure found in flowering plants (also known as angiosperms). It is responsible for producing seeds through sexual reproduction.

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It is responsible for producing seeds through sexual reproduction. Flowers can vary in size, shape, and color, and they are often fragrant to attract pollinators such as insects, birds, or bats. They consist of several parts including petals, sepals, stamens, and pistils. The petals are usually brightly colored to attract pollinators, while the sepals protect the developing bud. The stamens produce pollen, which is transferred to the pistil, where fertilization takes place. After fertilization, the ovary of the flower develops into a fruit, containing seeds for reproduction. Flowers have been cultivated and used for various purposes by humans throughout history, such as for decoration, ceremonies, and as a symbol of love or mourning.

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