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Monoecious
Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system alongside gynomonoecy, andromonoecy and trimonoecy. Monoecy is connected to anemophily. It can prevent self-pollination in an individual flower but cannot prevent self-pollination between male and female flowers on the same plant. Monoecy in angiosperms has been of interest for evolutionary biologists since Charles Darwin. Terminology Monoecious comes from the Greek words for one house. History The term monoecy was first introduced in 1735 by Carl Linnaeus. Darwin noted that the flowers of monoecious species sometimes showed traces of the opposite sex function. Monoecious hemp was first reported in 1929. Occurrence Monoecy is most common in temperate climates and is often associated with inefficient pollinators or wind-pollinated plants. It may be beneficial to reducing pollen-stigma interferenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoecy
Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system alongside gynomonoecy, andromonoecy and trimonoecy. Monoecy is connected to anemophily. It can prevent self-pollination in an individual flower but cannot prevent self-pollination between male and female flowers on the same plant. Monoecy in angiosperms has been of interest for evolutionary biologists since Charles Darwin. Terminology Monoecious comes from the Greek words for one house. History The term monoecy was first introduced in 1735 by Carl Linnaeus. Darwin noted that the flowers of monoecious species sometimes showed traces of the opposite sex function. Monoecious hemp was first reported in 1929. Occurrence Monoecy is most common in temperate climates and is often associated with inefficient pollinators or wind-pollinated plants. It may be beneficial to reducing pollen-stigma interferenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual System
A sexual system is a pattern of sex allocation or a distribution of male and female function across organisms in a species. Terms like reproductive system and mating system have also been used as synonyms. The distinction between sexual systems is not always clear due to phenotypic plasticity. Sexual systems are viewed as a key factor for genetic variation and reproductive success, and may have also led to the origin or extinction of certain species. Interests in sexual systems go back to Charles Darwin, Darwin, who found that barnacles contain species that are Androdioecy, androdioecious and some that are Dioecy, dioecious. Types of sexual systems In plants there are monomorphic sexual systems where a species has hermaphrodite, male and/or female flowers on the same plant. Monomorphic sexual systems include Monoecious (botany), monoecy, gynomonoecy, andromonoecy and trimonoecy. There are also dimorphic sexual systems like dioecy, gynodioecy and androdioecy. Mixed sexual syst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hermaphrodite
In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many Taxonomy (biology), taxonomic groups of animals (mostly invertebrates) do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which either partner can act as the female or male. For example, the great majority of tunicata, tunicates, pulmonate molluscs, opisthobranch, earthworms, and slugs are hermaphrodites. Hermaphroditism is also found in some fish species and to a lesser degree in other vertebrates. Most plants are also hermaphrodites. Animal species having different sexes, male and female, are called Gonochorism, gonochoric, which is the opposite of hermaphrodite. There are also species where hermaphrodites exist alongside males (called androdioecy) or alongside females (called gynodioecy), or all three exist in the same species ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gynomonoecy
Gynomonoecy is defined as the presence of both female and hermaphrodite flowers on the same individual of a plant species. It is prevalent in Asteraceae but is poorly understood. It is a monomorphic sexual system alongside monoecy, andromonoecy and trimonoecy. Occurrence This sexual system occurs in about 2.8% of flowering plants. It is present in 3% of ''Silene'' species and 23 families of flowering plants, but is most common in the daisy family, Asteraceae. About 200 of the approximately 23000 species in the Asteraceae are gynomonoecious. Evolution Gynomonoecy may be an intermediate evolutionary state between monoecy and hermaphroditism. It is also hypothesized to be the ancestor to trimonoecy. Gynomonecy evolved once in Hawaiian ''Tetramolopium''. In families like Compositae or Chenopodiaceae Amaranthaceae is a family of flowering plants commonly known as the amaranth family, in reference to its type genus ''Amaranthus''. It includes the former goosefoot family Cheno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andromonoecy
Andromonoecy is a breeding system of plant species in which male and hermaphrodite flowers are on the same plant. It is a monomorphic sexual system alongside monoecy, gynomonoecy and trimonoecy. Andromonoecy is frequent among genera with zygomorphic flowers, however it is overall rare and occurs in less than 2% of plant species. Nonetheless the breeding system has gained interest among biologists in the study of sex expression. Etymology The word andromonoecious is a combination of andr- (meaning male) and monoecious and was first used in 1877. Prevalence It is uncommon and has been estimated to occur in less than 2% of plant species. In angiosperms, it occurs in 1.7% of angiosperms making up around 4000 species in 33 families. It is common in the grass subfamily Panicoideae. Andromonoecious species * ''Cucumis melo'' subsp * ''Cucumis melo'' * '' Chaerophyllum bulbosum'' * ''Erophaca baetica'' * ''Silene tibetica'' ''Solanum'' * ''Solanum agnewiorum'' * ''Solanum aur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxford University Press
Oxford University Press (OUP) is the university press of the University of Oxford. It is the largest university press in the world, and its printing history dates back to the 1480s. Having been officially granted the legal right to print books by decree in 1586, it is the second oldest university press after Cambridge University Press. It is a department of the University of Oxford and is governed by a group of 15 academics known as the Delegates of the Press, who are appointed by the vice-chancellor of the University of Oxford. The Delegates of the Press are led by the Secretary to the Delegates, who serves as OUP's chief executive and as its major representative on other university bodies. Oxford University Press has had a similar governance structure since the 17th century. The press is located on Walton Street, Oxford, opposite Somerville College, in the inner suburb of Jericho. For the last 500 years, OUP has primarily focused on the publication of pedagogical texts and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spermatophyte
A spermatophyte (; ), also known as phanerogam (taxon Phanerogamae) or phaenogam (taxon Phaenogamae), is any plant that produces seeds, hence the alternative name seed plant. Spermatophytes are a subset of the embryophytes or land plants. They include most familiar types of plants, including all flowers and most trees, but exclude some other types of plants such as ferns, mosses, algae. The term ''phanerogams'' or ''phanerogamae'' is derived from the Greek (), meaning "visible", in contrast to the cryptogamae (), together with the suffix (), meaning "to marry". These terms distinguished those plants with hidden sexual organs (cryptogamae) from those with visible sexual organs (phanerogamae). Description The extant spermatophytes form five divisions, the first four of which are traditionally grouped as gymnosperms, plants that have unenclosed, "naked seeds": * Cycadophyta, the cycads, a subtropical and tropical group of plants, * Ginkgophyta, which includes a single living s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disruptive Selection
Disruptive selection, also called diversifying selection, describes changes in population genetics in which extreme values for a trait are favored over intermediate values. In this case, the variance of the trait increases and the population is divided into two distinct groups. In this more individuals acquire peripheral character value at both ends of the distribution curve. Overview Natural selection is known to be one of the most important biological processes behind evolution. There are many variations of traits, and some cause greater or lesser reproductive success of the individual. The effect of selection is to promote certain alleles, traits, and individuals that have a higher chance to survive and reproduce in their specific environment. Since the environment has a carrying capacity, nature acts on this mode of selection on individuals to let only the most fit offspring survive and reproduce to their full potential. The more advantageous the trait is the more com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amaranth
''Amaranthus'' is a cosmopolitan genus of annual or short-lived perennial plants collectively known as amaranths. Some amaranth species are cultivated as leaf vegetables, pseudocereals, and ornamental plants. Catkin-like cymes of densely packed flowers grow in summer or autumn. Amaranth varies in flower, leaf, and stem color with a range of striking pigments from the spectrum of maroon to crimson and can grow longitudinally from tall with a cylindrical, succulent, fibrous stem that is hollow with grooves and bracteoles when mature. There are approximately 75 species in the genus, 10 of which are dioecious and native to North America with the remaining 65 monoecious species endemic to every continent (except Antarctica) from tropical lowlands to the Himalayas. Members of this genus share many characteristics and uses with members of the closely related genus ''Celosia''. Amaranth grain is collected from the genus. The leaves of some species are also eaten. Description Amar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercurialis Annua
''Mercurialis annua'' is a species of flowering plant in the spurge family Euphorbiaceae known by the common name annual mercury or (rarely) French mercury. It is native to Europe, North Africa, and the Middle East but it is known on many other continents as an introduced species. Description This is an annual herb growing 10 to 70 centimeters tall with oppositely arranged, stipulate oval leaves each a few centimeters long. The male flowers are borne in spikelike clusters sprouting from leaf axils, and female flowers grow at leaf axils in clusters of 2 or 3. The fruit is a bristly schizocarp 2 or 3 millimeters wide containing shiny, pitted seeds. The species is monoecious or androdioecious. A plant of ''Mercurialis annua'' can produce up to 135 million pollen grains. Phytochemistry Isorhamnetin-3-rutinoside-4′-glucoside, rutin, narcissin ( Isorhamnetin 3-rutinoside), quercetin-3-(2G-glucosyl)-rutinoside and isorhamnetin-3-rutinoside-7-glucoside can be isolated fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Empetrum Nigrum Subsp
''Empetrum'' is a genus of three species of dwarf evergreen shrubs in the heath family Ericaceae. They are commonly known as crowberries and bear edible fruit. They are commonly found in the northern hemisphere, from temperate to subarctic climates, and also in the Southern Andes of South America and on the South Atlantic islands of South Georgia, the Falklands and Tristan da Cunha. The typical habitat is on moorlands, tundra, muskeg and spruce forests. They are also often found in areas of coastal exposure on the sand dunes and dune slacks. Species of ''Empetrum'' include: '' E. nigrum'' (crowberry or black crowberry) and its tetraploid subspecies ''E. nigrum'' ssp. ''hermaphroditum'', '' E. eamesii'' (rockberry or purple crowberry) and '' E. rubrum'' (red crowberry). All are evergreen mat forming shrubs, with small, light green needle-like leaves 3–10 mm long. The flowers are small and either bisexual or dioecious. The fruit is a fairly dry berry. The plant has slender, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Empetrum Nigrum
''Empetrum nigrum'', crowberry, black crowberry, or, in western Alaska, blackberry, is a flowering plant species in the heather family Ericaceae with a near circumboreal distribution in the Northern Hemisphere. It is usually dioecious, but there is a bisexual tetraploid subspecies, ''Empetrum nigrum'' subsp. ''hermaphroditum'', which occurs in more northerly locations and at higher altitude. Description ''Empetrum nigrum'' is a low growing, evergreen shrub with a creeping habit. The leaves are long, arranged alternately along the stem. The stems are red when young and then fade to brown. It blooms between May and June. The flowers are small and not very noticeable, with greenish-pink sepals that turn reddish purple. The round fruits are drupes, wide, usually black or purplish-black but occasionally red. The metabolism and photosynthetic parameters of ''Empetrum'' can be altered in winter-warming experiments. Subspecies * ''Empetrum nigrum'' subsp. ''asiaticum'' (Nakai ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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