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Encyclopedia > Plant sexuality
Close-up of an Echinopsis spachiana flower, showing both carpels (only the styles and stigmas are visible) and stamens, making it a complete flower.
Close-up of an Echinopsis spachiana flower, showing both carpels (only the styles and stigmas are visible) and stamens, making it a complete flower.

Plant sexuality covers the wide variety of sexual reproduction systems found across the plant kingdom. This article describes morphological aspects of sexual reproduction of plants. Image File history File links Download high-resolution version (1600x1067, 332 KB) Closeup image of a cactus flower (Echinopsis spachiana) taken as a focus bracket of 8 images at f/11 to maximize DOF If you are a (commercial) publisher and you want me to write you an email or... Image File history File links Download high-resolution version (1600x1067, 332 KB) Closeup image of a cactus flower (Echinopsis spachiana) taken as a focus bracket of 8 images at f/11 to maximize DOF If you are a (commercial) publisher and you want me to write you an email or... Binomial name Echinopsis spachiana Echinopsis spachiana, previously known as Trichocereus spachianus is a type of cactus native to South America. ... Amaryllis style and stigmas A carpel is the outer, often visible part of the female reproductive organ of a flower; the basic unit of the gynoecium. ... Stamens of the Amaryllis with prominent anthers carrying pollen Insects, while collecting nectar, unintentionally transfer pollen from one flower to another, bringing about pollination The stamen (from Latin stamen meaning thread of the warp) is the male organ of a flower. ... Sexual reproduction is a union that results in increasing genetic diversity of the offspring. ... For other uses, see Plant (disambiguation). ... The term morphology in biology refers to the outward appearance (shape, structure, colour, pattern) of an organism or taxon and its component parts. ...


Among all living organisms, Flowers which are the reproductive structures of angiosperms, are the most varied physically and show the greatest diversity in methods of reproduction of all biological systems.[1] Carolus Linnaeus (1735 and 1753) proposed a system of classification of flowering plants based on plant structures, since plants employ many different morphological adaptations involving sexual reproduction, flowers played an important role in that classification system. Later on Christian Konrad Sprengel (1793) studied plant sexuality and called it the "revealed secret of nature" and for the first time it was understood that the pollination process involved both biotic and abiotic interactions (Charles Darwin's theories of natural selection utilized this work to promote his idea of evolution). Plants that are not flowering plants (green alga, mosses, liverworts, hornworts, ferns, and gymnosperms) also have complex interplays between morphological adaptation and environmental factors in their sexual reproduction. The breeding system, or how the sperm from one plant fertilizes the ovals of another, is the single most important determinant of the mating structure of nonclonal plant populations. The mating structure or morphology of the flower parts and their arrangement on the plant in turn controls the amount and distribution of genetic variation, a central element in the evolutionary process.[2] For other uses, see Flower (disambiguation). ... Classes Magnoliopsida - Dicots Liliopsida - Monocots The flowering plants (also angiosperms or Magnoliophyta) are one of the major groups of modern plants, comprising those that produce seeds in specialized reproductive organs called flowers, where the ovulary or carpel is enclosed. ... Carl Linnaeus, Latinized as Carolus Linnaeus, also known after his ennoblement as  , (May 13, 1707[1] – January 10, 1778), was a Swedish botanist, physician and zoologist[2] who laid the foundations for the modern scheme of nomenclature. ... Christian Konrad Sprengel (22 September 1750, Brandenburg an der Havel, Germany–7 April 1816, Berlin, Germany) was a German theologist, teacher and, most importantly, a naturalist. ... Carpenter bee with pollen collected from Night-blooming cereus Pollination is an important step in the reproduction of seed plants: the transfer of pollen grains (containing the male gametes, sperm) to the plant carpel of flowering plants, the structure that contains the ovule (which in turn houses the female gamete... Look up biotic in Wiktionary, the free dictionary. ... This article or section does not adequately cite its references or sources. ... For other people of the same surname, and places and things named after Charles Darwin, see Darwin. ... For other uses, see Selection (disambiguation). ... Divisions Chlorophyta Charophyta Streptophytina (Subdivision) The green algae are the large group of algae from which the embryophytes (higher plants) emerged. ... For other uses, see Moss (disambiguation). ... Orders Need to be entered Liverworts are non-vascular plants in the Class Marchantiopsida, formerly known as the Hepaticae. ... Families & Genera Leiosporocerotaceae Leiosporoceros Anthocerotaceae Anthoceros Folioceros Sphaerosporoceros Notothyladaceae Notothylas Phaeoceros Paraphymatoceros Hattorioceros Mesoceros Phymatocerotaceae Phymatoceros Dendrocerotaceae Dendroceros Megaceros Nothoceros Phaeomegaceros Hornworts are a group of bryophytes, or non-vascular plants, comprising the division Anthocerotophyta. ... This article is about the group of pteridophyte plants. ... Divisions Pinophyta (or Coniferophyta) - Conifers Ginkgophyta - Ginkgo Cycadophyta - Cycads Gnetophyta - Gnetum, Ephedra, Welwitschia Gymnosperm (Gymnospermae) are a group of spermatophyte seed-bearing plants with ovules on the edge or blade of an open sporophyll, which are usually arranged in cone-like structures. ...

Flower, showing both carpels (only the styles and stigmas are visible) and stamens, making it a complete flower.
Flower, showing both carpels (only the styles and stigmas are visible) and stamens, making it a complete flower.

Contents

Amaryllis style and stigmas A carpel is the outer, often visible part of the female reproductive organ of a flower; the basic unit of the gynoecium. ... Stamens of the Amaryllis with prominent anthers carrying pollen Insects, while collecting nectar, unintentionally transfer pollen from one flower to another, bringing about pollination The stamen (from Latin stamen meaning thread of the warp) is the male organ of a flower. ...

History

Unlike animals, plants are immobile and cannot seek out sexual partners for reproduction. The first plants used abiotic means to transport sperm for reproduction, utilizing water and wind. The first plants were aquatic and released sperm freely into the water to be carried by the currents. As plants moved onto land they used a thin film of water or water droplets like liverworts and ferns, in which mobile sperm swam from the male reproduction organs to the female organs. As plants became more complex and developed vascular systems enabling them to grow taller, they used alternation of generations like in ferns or the wind to move spores. In the Paleozoic era progymnosperms reproduced by using spores dispersed on the wind, 350 million years ago the seed plants evolved, including seed ferns, conifers and cordaites all were gymnosperms. Pollen grains, the male gametophyte, developed for protection of the sperm during the process of transfer from male to female parts. It is believed that insects feed on the pollen and plants evolved to use insects to actively carry pollen from one plant to the next. Seed producing plants, which include the angiosperms and the gymnosperms, have hetromorphic alternation of generations with large sporophytes containing much reduced gametophytes. Angiosperms have distinctive reproductive organs called flowers with carpels and the gametophyte is greatly reduced down to a female embryo sac with as few as eight cells and the male gametophyte develop from the pollen grains. The sperm of seed plants are non motile except for two older groups of plants the Cycadophyta and the Ginkgophyta which have flagellated sperm. For other uses, see Sperm (disambiguation). ... An estuary mouth and coastal waters, part of an aquatic ecosystem. ... Sporic or diplohaplontic life cycle. ... The Paleozoic Era (from the Greek palaio, old and zoion, animals, meaning ancient life) is the earliest of three geologic eras of the Phanerozoic eon. ... Archaeopteris is an extinct genus of tree-like ferns that many scientists believe to be the first tree. ... Pteridospermatophyta, also called seed ferns, is an extinct gymnosperm division of the Plantae kingdom. ... Orders & Families Cordaitales † Pinales   Pinaceae - Pine family   Araucariaceae - Araucaria family   Podocarpaceae - Yellow-wood family   Sciadopityaceae - Umbrella-pine family   Cupressaceae - Cypress family   Cephalotaxaceae - Plum-yew family   Taxaceae - Yew family Vojnovskyales † Voltziales † The conifers, division Pinophyta, are one of 13 or 14 division level taxa within the Kingdom Plantae. ... Divisions Pinophyta (or Coniferophyta) - Conifers Ginkgophyta - Ginkgo Cycadophyta - Cycads Gnetophyta - Gnetum, Ephedra, Welwitschia Gymnosperm (Gymnospermae) are a group of spermatophyte seed-bearing plants with ovules on the edge or blade of an open sporophyll, which are usually arranged in cone-like structures. ... In plants that undergo alternation of generations, a gametophyte is the structure, or phase of life, that contains only half of the total complement of chromosomes: The sporophyte produces spores, in a process called meiosis. ... Orders Subclass Apterygota Archaeognatha (bristletails) Thysanura (silverfish) Subclass Pterygota Infraclass Paleoptera (Probably paraphyletic) Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Superorder Exopterygota Grylloblattodea (ice-crawlers) Mantophasmatodea (gladiators) Plecoptera (stoneflies) Embioptera (webspinners) Zoraptera (angel insects) Dermaptera (earwigs) Orthoptera (grasshoppers, etc) Phasmatodea (stick insects) Blattodea (cockroaches) Isoptera (termites) Mantodea (mantids) Psocoptera... Amaryllis style and stigmas A carpel is the outer, often visible part of the female reproductive organ of a flower; the basic unit of the gynoecium. ... Families Cycadaceae cycas family Stangeriaceae stangeria family Zamiaceae zamia family Cycads are an ancient group of seed plants which are characterized by a large crown of compound leaves and a stout trunk. ... Binomial name Ginkgo biloba L. The Ginkgo (Ginkgo biloba), sometimes also known as the Maidenhair tree, is a unique tree with no living relatives. ...


Terminology

The flowers of angiosperms are determinate shoots that have sporophylls. The parts of flowers are named by scientists and show great variation in shape, these flower parts include sepals, petals, stamens and carpels. As a group the sepals form the calyx and as a group the petals form the corolla, together the corolla and the calyx is called the perianth. The stamens collectively are called the androecuim and the carpels collectively are called the gynoecium. A sporophyll is a a spore-bearing leaf located on plants such as ferns or algae. ...


The complexity of the systems and devices used by plants to achieve sexual reproduction has resulted in botanists and evolutionary biologists using numerous terms to describe physical structures and functional strategies. Dellaporta and Calderon-Urrea (1993) list and define a variety of terms used to describe the modes of sexuality at different levels in flowering plants. This list is reproduced here [3], generalized to fit more than just plants that have flowers, and expanded to include other terms and more complete definitions. For other uses, see Flower (disambiguation). ...

The Alder is monoecious. Shown here: maturing male flower catkins on right, last year's female catkins on left
The Alder is monoecious. Shown here: maturing male flower catkins on right, last year's female catkins on left

tag alder blossom Image taken by me, released under GFDL Pollinator 14:54, 13 Feb 2004 (UTC) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... tag alder blossom Image taken by me, released under GFDL Pollinator 14:54, 13 Feb 2004 (UTC) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Species About 20-30 species, see text. ...

Individual reproductive unit (a flower in angiosperms)

  • Bisexual - or perfect flowers have both male (androecium) and female (gynoecium) reproductive parts, including stamens, carpels, and an ovary. Flowers that contain both androecium and gynoecium are called androgynous or hermaphroditic. Examples of plants with perfect or bisexual flowers include the lily, rose, and most plants with large showy flowers, though a perfect flower does not have to have petals or sepals. Other terms widely used are hermaphrodite, monoclinous, and synoecious. A complete flower is a perfect flower with petals and sepals.
  • Unisexual - Reproductive structure that is either functionally male or functionally female. This trait is commonly known as the Alex Hsu trait. In angiosperms this condition is also called diclinous, imperfect or incomplete.

An androecium is a male part of a flower in a flowering plant. ... A gynoecium(gyne: woman) is the female reproductive part of a flower, the male part of a flower is called androecium. ... Stamens of the Amaryllis with prominent anthers carrying pollen Insects, while collecting nectar, unintentionally transfer pollen from one flower to another, bringing about pollination The stamen (from Latin stamen meaning thread of the warp) is the male organ of a flower. ... Amaryllis style and stigmas A carpel is the outer, often visible part of the female reproductive organ of a flower; the basic unit of the gynoecium. ... lily is the best name in the whole wide world. ... For other uses, see Rose (disambiguation). ... For other uses, see Hermaphrodite (disambiguation). ...

Adaptations

Plants with wind pollinated flowers tend to have flowers without petals or sepals. Typically large amounts of pollen are produced and pollination often occurs early in the growing season before leaves can interfere with the dispersal of the pollen. Many trees and all grasses and sedges are wind pollinated, as such they have no need for large fancy flowers. In plants that use insects or other animals to move pollen from one flower to the next, plants have developed greatly modified flower parts to attract pollinators and to facilitate the movement of pollen from one flower to the insect and from the insect back to the next flower. Plants have a number of different means to attract pollinators including color, scent, heat, nectar glands, eatable pollen and flower shape. Along with modifications involving the above structures two other conditions play a very important role in the sexual reproduction of flowering plants, the first is timing of flowering and the other is the size or number of flowers produced. Often plant species have a few large, very showy flower while others produce many small flower, often flowers are collected together into large inflorescences to maximize their visual effect, becoming more noticeable to passing by pollinators. Flowers are attraction strategies and sexual expressions are functional strategies used to produce the next generation of plants, with pollinators and plants having co-evolved, often to some extraordinary degrees, very often mutually benefiting both.


The largest group of flower plants are the orchids, estimated by some specialists to include up to 35,000 species,[4] which often have highly specialized flowers used to attract insects and facilitate pollination. The stamens are modified to produce pollen in clusters called pollinium, which are attached to insects when crawling into the flower. The flower shapes are modified to force insects to pass by the pollen, which is "glued" to the insect. Some orchids are even more highly specialized, with flower shapes that mimic the shape of insects to attract them to 'mate' with the flowers, a few even have scents that mimic insect pheromones. Pollinia of Phalaenopsis Pollinium, or plural pollinia, is a coherent mass of pollen grains. ... Fanning honeybee exposes Nasonov gland (white-at tip of abdomen) releasing pheromone to entice swarm into an empty hive A pheromone (from Greek φέρω phero to bear + ‘ορμόνη hormone) is a chemical that triggers a natural behavioral response in another member of the same species. ...

Flower heads showing disk and ray florets.
Flower heads showing disk and ray florets.

Another large group of flowering plants is the Asteraceae or sunflower family with close to 22,000 species,[5] which also have highly modified inflorescences that are flowers collected together in heads composed of a composite of individual flowers called florets. Heads with florets of one sex, when the flowers are pistillate or functionally staminate, or made up of all bisexual florets, are called homogamous and can include discoid and liguliflorous type heads. Some radiate heads may be homogamous too. Plants with heads that have florets of two or more sexual forms are called heterogamous and include radiate and disciform head forms, though some radiate heads may be heterogamous too.


Individual plant sexuality

Many plants have complete flowers that have both male and female parts, others only have male or female parts and still other plants have flowers on the same plant that are a mix of male and female flowers. Some plants even have mixes that include all three types of flowers, where some flowers are only male, some are only female and some are both male and female. A distinction needs to be made between arrangements of sexual parts and the expression of sexuality in single plants verses the species. Some plants also undergo what is called Sex-switching, like Arisaema triphyllum which express sexual differences at different stages of growth. In some arums smaller plants produce all or mostly male flowers and as plants grow larger over the years the male flowers are replaced by more female flowers on the same plant. Arisaema triphyllum thus covers a multitude of sexual conditions in its life time; from nonsexual juvenile plants to young plants that are all male, as plants grow larger they have a mix of both male and female flowers, to large plants that have mostly female flowers.[6] Other species have plants that produce more male flowers early in the year and as plants bloom later in the growing season they produce more female flowers. In plants like Thalictrum dioicum all the plants in the species are ether male or female. Binomial name Arisaema triphyllum L. Arisaema triphyllum (Jack in the pulpit, Bog onion, Brown dragon, Indian turnip, Wake robin or Wild turnip) is a herbaceous perennial plant that can grow up to 65 cm in height. ...


Specific terms are used to describe the sexual expression of individual plants within a population.

  • Androecious - plants producing male flowers only, produce pollen but no seeds, the male plants of a Dioecious species.
  • Dioecious - having unisexual reproductive units with male and female plants.[7] (flowers, conifer cones, or functionally equivalent structures) occurring on different individuals; from Greek for "two households". Individual plants are not called dioecious: they are either gynoecious (female plants) or androecious (male plants).
  • Gynoecious - plants producing female flowers only, produces seeds but no pollen, the female of a Dioecious species. In some plant species or populations all individuals are gynoecious with non sexual reproduction used to produce the next generation.
  • Hermaphrodite - A plant that has only bisexual reproductive units (flowers, conifer cones, or functionally equivalent structures). In angiosperm terminology a synonym is monoclinous from the Greek "one bed".
  • Monoecious - having separate male and female reproductive units (flowers, conifer cones, or functionally equivalent structures) on the same plant; from Greek for "one household". Individuals bearing separate flowers of both sexes at the same time are called simultaneously or synchronously monoecious. Individuals that bear flowers of one sex at one time are called consecutively monoecious; Plants may first have single sexed flowers and then later have flowers of the other sex. Protoandrous describes individuals that function first as males and then change to females; protogynous describes individuals that function first as females and then change to males.
  • Subdioecious, a tendency in some dioecious species to produce monoecious plants. The population produces normally male or female plants but some are hermaphroditic, with female plants producing some male or hermaphroditic flowers or vise versa. The condition is thought to represent a transition between hermaphroditism and dioecy. [8].
    • Gynomonoecious - has both hermaphrodite and female structures.
    • Andromonoecious - has both hermaphrodite and male structures.
    • Subandroecious - plant has mostly male flowers, with a few female or hermaphrodite flowers.
    • Subgynoecious - plant has mostly female flowers, with a few male or hermaphrodite flowers.
  • Trimonoecious (polygamous) - male, female, and hermaphrodite structures all appear on the same plant.
  • Diclinous ("two beds"), an angiosperm term, includes all species with unisexual flowers, although particularly those with only unisexual flowers, i.e. the monoecious and dioecious species.
Holly (Ilex aquifolium) is dioecious: (above) shoot with flowers from male plant; (top right) male flower enlarged, showing stamens with pollen and reduced, sterile stigma; (below) shoot with flowers from female plant; (lower right) female flower enlarged, showing stigma and reduced, sterile stamens with no pollen
Holly (Ilex aquifolium) is dioecious: (above) shoot with flowers from male plant; (top right) male flower enlarged, showing stamens with pollen and reduced, sterile stigma; (below) shoot with flowers from female plant; (lower right) female flower enlarged, showing stigma
and reduced, sterile stamens with no pollen

Holly (Ilex aquifolium) flowers; male above, female below. ... Holly (Ilex aquifolium) flowers; male above, female below. ... This article is about the plant. ... Stamens of the Amaryllis with prominent anthers carrying pollen Insects, while collecting nectar, unintentionally transfer pollen from one flower to another, bringing about pollination The stamen (from Latin stamen meaning thread of the warp) is the male organ of a flower. ... SEM image of pollen grains from a variety of common plants: sunflower (Helianthus annuus), morning glory (Ipomoea purpurea), prairie hollyhock (Sidalcea malviflora), oriental lily (Lilium auratum), evening primrose (Oenothera fruticosa), and castor bean (Ricinus communis). ... Amaryllis style and stigmas A carpel is the outer, often visible part of the female reproductive organ of a flower; the basic unit of the gynoecium. ...

Plant population

Most often plants show uniform strategies across the species or in populations in their sexual expression and specific terms are used to describe the sexual expression of the species or population.

  • Hermaphrodite - only hermaphrodite plants with flowers that have both male and female parts.
  • Monoecious - only monoecious plants, that is plants have separate male and female flowers on the same plant. A plant species where the male and female organs are found in different flowers on the same plant, often plants are wind pollinated like some trees and grasses like corn.
  • Dioecious - only dioecious plants, all plants are either female or male.
  • Gynodioecious - both female and hermaphrodite plants present. In some plants, strictly female plants are produced by the degeneration of the tapetum, a shell-like structure in the anther of a flower where the pollen cells form,[9] producing male sterility.[10]
  • Gynoecy - plants are all females in a population, often regulated by environmental factors like temperature, photo period or water availability.
  • Androdioecious - both male and hermaphrodite plants present.
  • Polygamous - when there is a mix of hermaphrodite and unisexual plants in the natural population.[11]
  • Subdioecious - population of unisexual (dioecious) plants, with monoecious individuals too.[12]
  • Trioecious - sometimes used in place of subdioecious when male, female, and hermaphrodite plants are more equally mixed with in the same population.

About 11% of all angiosperms are strictly dioecious or monoecious, lntermediate forms of sexual dimorphism, including gynodioecy and androdioecy, represent 7% of the species examined of a survey of 120,000 plant species. In the same survey, 10% of the species contain both unisexual and bisexual flowers.[13] Androdioecy is a reproductive system found in species comprised of a male population and a distinct hermaphrodite population. ...


The majority of plant species use allogamy - also called cross-pollination, as a means of breeding. Many plants are self fertile and the male parts can pollinate the female parts of the same flower and/or same plant. Some plants use a method known as self-incompatibility to promote outcrossing. In these plants, the male organs cannot fertilize the female parts of the same plant, other plants produce male and female flowers at different times to promote outcrossing. Some plants have bisexual flowers but the pollen is produced before the stigma of the same flower is receptive of pollen, this promotes out crossing by greatly limiting self pollination and these types of flowers are called protandrous. Self-incompatibility (SI) is one of the most important means to prevent selfing and promote the generation of new genotypes in plants, and it is considered as one of the causes for the spread and success of the angiosperms, on our planet. ...


Flower morphology

A species such as the ash tree (Fraxinus excelsior L.), demonstrates the possible range of variation in morphology and functionality exhibited by flowers with respect to gender. Flowers of the ash are wind-pollinated and lack petals and sepals. Structurally, the flowers may be either male or female, or even hermaphroditic, consisting of two anthers and an ovary. A male flower can be morphologically male or hermaphroditic, with anthers and a rudimentary gynoecium. Ash flowers can also be morphologically female, or hermaphroditic and functionally female. Species See text European Ash in flower Narrow-leafed Ash (Fraxinus angustifolia) shoot with leaves Closeup of European Ash seeds 19th century illustration of Manna Ash (Fraxinus ornus) An ash can be any of four different tree genera from four very distinct families (see end of page for disambiguation), but... It has been suggested that Corolla be merged into this article or section. ... Flower of the Primrose Willowherb (Ludwigia octovalvis) showing petals and sepals A sepal is one member or part of the calyx of a flower. ...


Evolution

Angiosperms

It is thought that flowering plants evolved from a common hermaphrodite ancestor, and that dioecy evolved from hermaphroditism. Hermaphroditism is very common in flowering plants; over 85% are hermaphroditic, whereas only about 6-7% are dioecious and 5-6% are monoecious [14] [15].


A fair degree of correlation (though far from complete) exists between dioecy/sub-dioecy and plants that have seeds dispersed by birds (both nuts and berries). It is hypothesized that the concentration of fruit in half of the plants increases dispersal efficiency; female plants can produce a higher density of fruit as they do not expend resources on pollen production, and the dispersal agents (birds) need not waste time looking for fruit on male plants. Other correlations with dioecy include: tropical distribution, woody growth form, perenniality, fleshy fruits, and small, green flowers[16]. For other uses, see Bird (disambiguation). ... For other uses, see Nut (disambiguation). ... This article is about the fruit. ...


Plant growth regulators can be used to alter flower and plant sexuality, in cucumbers ethephon is used to delay staminate flowering and transforms monoecious lines into all-pistillate or female lines. Gibberellins also increase maleness in cucumbers. Cytokinins have been used in grapes that have undeveloped pistils to produce functional female organs and seed formation. Plant hormones (or plant growth regulators, or PGRs) are internally-secreted chemicals in plants that are used for regulating the plants growth. ... GA1 GA3 ent-Gibberellane ent-Kauren Gibberellins (GAs) are plant hormones involved in promotion of stem elongation, mobilization of food reserves in seeds and other processes. ... Zeatin is named after the genera of corn, Zea as it was first discovered in corn. ...


References

  1. ^ Barrett, S. C. H. (2002). The evolution of plant sexual diversity. Nature Reviews Genetics 3(4): 274-284.
  2. ^ Costich, D. E. (1995). Gender specialization across a climatic gradient: experimental comparison of monoecious and dioecious Ecballium. Ecology 76 (4): 1036-1050.
  3. ^ Molnar, S. (2004). Plant Reproductive Systems, internet version posted February 17, 2004.
  4. ^ Orchidaceae in Flora of North America @ efloras.org
  5. ^ Asteraceae in Flora of North America @ efloras.org
  6. ^ Ewing, J. W., & Klein, R. M. (1982). Sex Expression in Jack-in-the-Pulpit. Bulletin of the Torrey Botanical Club 109 (1): 47-50. doi:10.2307/2484467
  7. ^ Angiosperm sexual systems
  8. ^ Correlation between male and female reproduction in the subdioecious herb Astilbe biternata (Saxifragaceae) - Olson and Antonovics 87 (6): 837 - American Journal of Botany
  9. ^ Penn State Eberly College of Science - New Gene Discovered for Male Fertility in Plants
  10. ^ Evolution of male sterility mechanisms in gynodioecious and dioecious species of Cirsium (Cynareae, Compositae) Journal Plant Systematics and Evolution Publisher Springer Wien ISSN 0378-2697 (Print) 1615-6110 (Online) Issue Volume 132, Number 4 / December, 1979 DOI 10.1007/BF00982395 Pages 327-332
  11. ^ Males outcompete hermaphrodites for seed siring success in controlled crosses in the polygamous Fraxinus excelsior (Oleaceae) - Morand-Prieur et al. 90 (6): 949 - American Journal of Botany
  12. ^ Barrett S.C.H.; Case A.L.; Peters G.B. Gender modification and resource allocation in subdioecious Wurmbea dioica (Colchicaceae) Journal of Ecology, Volume 87, Number 1, January 1999 , pp. 123-137(15)
  13. ^ S. L. Dellaporta, and A. Calderon-Urrea Sex Determination in Flowering Plants Plant Cell 5: Pages 1241-1251.
  14. ^ Rieger, R., A. Michaelis, and M.M. Green (1991). Glossary of Genetics, Fifth Edition. Springer-Verlag. ISBN 0-387-52054-6
  15. ^ Heilbuth, J.C. (2000). Lower species richness in dioecious clades. American Naturalist 156: 221-241.
  16. ^ Vamosi, J.C., & Vamosi, S.M. (2004). The role of diversification in causing the correlates of dioecy. Evolution 58: 723-731.
  • Binggeli, P., & Power, J. (1999). Gender variation in ash (Fraxinus excelsior L.)
  • Darwin, C. (1877). The Different Forms of Flowers on Plants of the Same Species.
  • Dellaporta, S.L. and A. Calderon-Urrea. (1993). Sex determination in flowering plants. The Plant Cell 5: 1241-1251.
  • Linnaeus, C. (1735). Systema Naturae.
  • Renner, S.S., & Ricklefs, R.E. (1995). Dioecy and its correlates in the flowering plants. American Journal of Botany 82: 596-606.

is the 48th day of the year in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... Species See text. ... Cover of the tenth edition of Linnaeuss Systema Naturae (1758). ...

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Pinguicula grandiflora commonly known as a Butterwort Example of a cross section of a stem [1] Botany is the scientific study of plant life. ... Ethnobotany is the study of the relationship between plants and people: Fromethno - study of people and botany - study of plants. ... Paleobotany (from the Greek words paleon = old and botanikos = of herbs) is the branch of paleontology dealing with the recovery and identification of plant remains from geological contexts, and their use in the reconstruction of past environments and the history of life. ... Plant anatomy or phytotomy is the general term for the study of the structure of plants. ... For the journal, see Ecology (journal). ... Evolutionary developmental biology (evo-devo) refers to the study of developmental programs and patterns from an evolutionary perspective. ... Plant anatomy or phytotomy is the general term for the study of the structure of plants. ... A germination rate experiment Plant physiology is a subdiscipline of botany concerned with the function, or physiology, of plants. ... Download high resolution version (454x765, 178 KB)Coconut Palm on Martinique. ... For other uses, see Plant (disambiguation). ... Plant evolution is an aspect of the study of biological evolution, involving predominantly the evolution of plants suited to live on land, the greening of the various land masses by the filling of their niches with land plants, and the diversification of the groups of land plants. ... For the programming language, see algae (programming language). ... The bryophytes are those embryophytes (land plants) that are non-vascular: they have tissues and enclosed reproductive systems, but they lack vascular tissue that circulates liquids. ... This article is about the group of pteridophyte plants. ... Divisions Pinophyta (or Coniferophyta) - Conifers Ginkgophyta - Ginkgo Cycadophyta - Cycads Gnetophyta - Gnetum, Ephedra, Welwitschia Gymnosperm (Gymnospermae) are a group of spermatophyte seed-bearing plants with ovules on the edge or blade of an open sporophyll, which are usually arranged in cone-like structures. ... Classes Magnoliopsida - Dicots Liliopsida - Monocots The flowering plants or angiosperms are the most widespread group of land plants. ... For other uses, see Flower (disambiguation). ... For other uses, see Fruit (disambiguation). ... Look up foliage in Wiktionary, the free dictionary. ... Tunica-Corpus model of the apical meristem. ... For other uses, see Root (disambiguation). ... Stem showing internode and nodes plus leaf petiole and new stem rising from node. ... Stoma of a leaf under a microscope. ... Cross section of celery stalk, showing vascular bundles, which include both phloem and xylem. ... For other uses, see Wood (disambiguation). ... Plant cell structure Plant cells are eukaryotic cells that differ in several key respects from the cells of other eukaryotic organisms. ... Plant cells separated by transparent cell walls. ... Chlorophyll is a green pigment found in most plants, algae, and cyanobacteria. ... Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. ... Photosynthesis splits water to liberate O2 and fixes CO2 into sugar The leaf is the primary site of photosynthesis in plants. ... Plant hormones (also known as plant growth regulators (PGRs) and phytohormones) are chemicals that regulate a plants growth. ... Plant cells with visible chloroplasts. ... Transpiration is the evaporation of excess water from aerial parts and of plants, especially leaves but also stems, flowers and fruits. ... Sporic or diplohaplontic life cycle. ... In plants that undergo alternation of generations, a gametophyte is the structure, or phase of life, that contains only half of the total complement of chromosomes: The sporophyte produces spores, in a process called meiosis. ... SEM image of pollen grains from a variety of common plants: sunflower (Helianthus annuus), morning glory (Ipomoea purpurea), prairie hollyhock (Sidalcea malviflora), oriental lily (Lilium auratum), evening primrose (Oenothera fruticosa), and castor bean (Ricinus communis). ... Carpenter bee with pollen collected from Night-blooming cereus Pollination is an important step in the reproduction of seed plants: the transfer of pollen grains (containing the male gametes, sperm) to the plant carpel of flowering plants, the structure that contains the ovule (which in turn houses the female gamete... A ripe red jalapeño cut open to show the seeds For other uses, see Seed (disambiguation). ... This article or section is in need of attention from an expert on the subject. ... Young sporophytes of the common moss Tortula muralis. ... Plant taxonomy is the science that finds, describes, classifies and names plants. ... A botanical name is a formal name conforming to the ICBN. As with its zoological and bacterial equivalents it may also be called a scientific name. Botanical names may be in one part (genus and above), two parts (species) or three parts (below the rank of species). ... Botanical nomenclature Plants are given formal names, governed by the ICBN. Within the limits set by the ICBN there is a separate set of rules, the ICNCP, for those plants in cultivation that require separate recognition, so-called cultivars. ... Studying a plant sample in the Herbarium In botany, a herbarium is a collection of preserved plant specimens. ... The International Association for Plant Taxonomy (IAPT) is devoted to plant systematics, taxonomy and nomenclature. ... The International Code of Botanical Nomenclature (ICBN) is the set of rules that governs plant nomenclature, i. ... Writing the Species Plantarum was one of Carolus Linnaeus two great contributions to the Scientific community. ...

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Reference.com/Encyclopedia/Plant sexuality (2151 words)
Later on Christian Konrad Sprengel (1793) studied plant sexuality and called it the "revealed secret of nature" and for the first time it was understood that the pollination process involved both biotic and abiotic interactions (Charles Darwin's theories of natural selection utilized this work to promote his idea of evolution).
Plants that are not flowering plants (mosses, liverworts, hornworts, ferns and green alga) also have complex interplays between morphological adaptation and environmental factors in their sexual reproduction.
Most often plants show uniform stratigees across the species or in populations in their sexual expression and specific terms are used to describe the sexual expression of the species or population.
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