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Magnoliids Of Australia
Magnoliids, Magnoliidae or Magnolianae are a clade of flowering plants. With more than 10,000 species, including magnolias, nutmeg, bay laurel, cinnamon, avocado, black pepper, tulip tree and many others, it is the third-largest group of angiosperms after the eudicots and monocots. The group is characterized by trimerous flowers, pollen with one pore, and usually branching-veined leaves. Some members of the subclass are among the earliest angiosperms and share anatomical similarities with gymnosperms like stamens that resemble the male cone scales of conifers and carpels found on the long flowering axis. According to molecular clock calculations, the lineage that led to magnoliids split from other plants about 135 million years ago or 160-165 million years ago. Classification "Magnoliidae" is the botanical name of a subclass, and "magnoliids" is an informal name that does not conform to the International Code of Nomenclature for algae, fungi, and plants. The circumscription of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aptian
The Aptian is an age (geology), age in the geologic timescale or a stage (stratigraphy), stage in the stratigraphic column. It is a subdivision of the Early Cretaceous, Early or Lower Cretaceous epoch (geology), Epoch or series (stratigraphy), Series and encompasses the time from 121.4 ± 1.0 annum, Ma to 113.0 ± 1.0 Ma (million years ago), approximately. The Aptian succeeds the Barremian and precedes the Albian, all part of the Lower/Early Cretaceous. The Aptian partly overlaps the upper part of the Western Europe, Western European Urgonian Stage. The Selli Event, also known as OAE1a, was one of two oceanic anoxic events in the Cretaceous Period, which occurred around 120 annum, Ma and lasted approximately 1 to 1.3 million years, being marked by enhanced silicate weathering, as well as ocean acidification. The Aptian extinction was a minor extinction event hypothesized to have occurred around 116 to 117 Ma. Stratigraphic definitions The Aptian was named after the small city o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Merosity
Merosity (from the greek "méros," which means "having parts")) refers to the number of component parts in a distinct whorl of a plant structure. The term is most commonly used in the context of a flower where it refers to the number of sepals in a whorl of the calyx, the number of petals in a whorl of the corolla, the number of stamens in a whorl of the androecium, or the number of carpels in a whorl of the gynoecium. The term may also be used to refer to the number of leaves in a leaf whorl. The adjective ''n''-merous refers to a whorl of ''n'' parts, where ''n'' is any integer greater than one. In nature, five or three parts per whorl have the highest frequency of occurrence, but four or two parts per whorl are not uncommon. Two consecutive whorls of dimerous petals are often mistaken for tetramerous petals. If all of the whorls in a given floral arrangement have the same merosity, the flower is said to be isomerous, otherwise the flower is anisomerous. For example, '' Trilli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Systems Of Plant Taxonomy
This list of systems of plant taxonomy presents "taxonomic systems" used in plant classification. A wiktionary:taxonomic system, taxonomic system is a coherent whole of taxonomy (biology), taxonomic judgments on circumscription (taxonomy), circumscription and placement of the considered taxa. It is only a "system" if it is applied to a large group of such taxa (for example, all the flowering plants). There are two main criteria for this list. A system must be taxonomic, that is deal with many plants, by their botanical names. Secondly it must be a system, i.e. deal with the relationships of plants. Although thinking about relationships of plants had started much earlier (see history of plant systematics), such systems really only came into being in the 19th century, as a result of an ever-increasing influx from all over the world of newly discovered plant species. The 18th century saw some early systems, which are perhaps precursors rather than full taxonomic systems. A mileston ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circumscription
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Circumscription may refer to: * Circumscribed circle * Circumscription (logic) *Circumscription (taxonomy) * Circumscription theory, a theory about the origins of the political state in the history of human evolution proposed by the American anthropologist Robert Carneiro *Electoral district An electoral (congressional, legislative, etc.) district, sometimes called a constituency, riding, or ward, is a geographical portion of a political unit, such as a country, state or province, city, or administrative region, created to provi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Code Of Nomenclature For Algae, Fungi, And Plants
The ''International Code of Nomenclature for algae, fungi, and plants'' (ICN or ICNafp) is the set of rules and recommendations dealing with the formal botanical names that are given to plants, fungi and a few other groups of organisms, all those "traditionally treated as algae, fungi, or plants".. It was formerly called the ''International Code of Botanical Nomenclature'' (ICBN); the name was changed at the International Botanical Congress in Melbourne in July 2011 as part of the ''Melbourne Code''. which replaced the ''Vienna Code'' of 2005. The current version of the code is the ''Shenzhen Code'' adopted by the International Botanical Congress held in Shenzhen, China, in July 2017. As with previous codes, it took effect as soon as it was ratified by the congress (on 29 July 2017), but the documentation of the code in its final form was not published until 26 June 2018. For fungi the ''Code'' was revised by the ''San Juan Chapter F'' in 2018. The 2025 edition of ICBN, the ''Ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subclass (biology)
In Taxonomy (biology), biological classification, class () is a taxonomic rank, as well as a taxonomic unit, a taxon, in that rank. It is a group of related taxonomic orders. Other well-known ranks in descending order of size are Domain (biology), domain, Kingdom (biology), kingdom, phylum, Order (biology), order, Family (biology), family, genus, and species, with class ranking between phylum and order. History The class as a distinct rank of biological classification having its own distinctive name – and not just called a ''top-level genus'' ''(genus summum)'' – was first introduced by France, French botanist Joseph Pitton de Tournefort in the classification of plants that appeared in his ''Eléments de botanique'' of 1694. Insofar as a general definition of a class is available, it has historically been conceived as embracing taxa that combine a distinct ''grade'' of organization—i.e. a 'level of complexity', measured in terms of how differentiated their organ systems ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Botanical Name
A botanical name is a formal scientific name conforming to the ''International Code of Nomenclature for algae, fungi, and plants'' (ICN) and, if it concerns a plant cultigen, the additional cultivar or cultivar group, Group epithets must conform to the ''International Code of Nomenclature for Cultivated Plants'' (ICNCP). The code of nomenclature covers "all organisms traditionally treated as algae, Fungus, fungi, or plants, whether fossil or non-fossil, including blue-green algae (Cyanobacteria), Chytridiomycota, chytrids, oomycetes, slime moulds and Photosynthesis, photosynthetic protists with their taxonomically related non-photosynthetic groups (but excluding Microsporidia)." The purpose of a formal name is to have a single name that is accepted and used worldwide for a particular plant or plant group. For example, the botanical name ''Bellis perennis'' denotes a plant species which is native to most of the countries of Europe and the Middle East, where it has accumulated variou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature Communications
''Nature Communications'' is a peer-reviewed, open access, scientific journal published by Nature Portfolio since 2010. It is a multidisciplinary journal that covers the natural sciences, including physics, chemistry, earth sciences, medicine, and biology. The journal has editorial offices in London, Berlin, New York City, and Shanghai. The founding editor-in-chief was Lesley Anson, followed by Joerg Heber, Magdalena Skipper, and Elisa De Ranieri. the editors are Nathalie Le Bot for health and clinical sciences, Stephane Larochelle for biological sciences, Enda Bergin for chemistry and biotechnology, and Prabhjot Saini for physics and earth sciences. Starting October 2014, the journal only accepted submissions from authors willing to pay an article processing charge. Until the end of 2015, part of the published submissions were only available to subscribers. In January 2016, all content became freely accessible. Starting from 2017, the journal offers a deposition ser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Million Years Ago
Million years ago, abbreviated as Mya, Myr (megayear) or Ma (megaannum), is a unit of time equal to (i.e. years), or approximately 31.6 teraseconds. Usage Myr is in common use in fields such as Earth science and cosmology. Myr is also used with Mya or Ma. Together they make a reference system, one to a quantity, the other to a particular point in a year numbering system that is ''time before the present''. Myr is deprecated in geology, but in astronomy ''Myr'' is standard. Where "myr" ''is'' seen in geology, it is usually "Myr" (a unit of mega-years). In astronomy, it is usually "Myr" (Million years). Debate In geology, a debate remains open concerning the use of ''Myr'' (duration) plus ''Mya'' (million years ago) versus using only the term ''Ma''. In either case, the term '' Ma'' is used in geology literature conforming to ISO 31-1 (now ISO 80000-3) and NIST 811 recommended practices. Traditional style geology literature is written: The "ago" is implied, so that any s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Clock
The molecular clock is a figurative term for a technique that uses the mutation rate of biomolecules to deduce the time in prehistory when two or more life forms diverged. The biomolecular data used for such calculations are usually nucleotide sequences for DNA, RNA, or amino acid sequences for proteins. Early discovery and genetic equidistance The notion of the existence of a so-called "molecular clock" was first attributed to Émile Zuckerkandl and Linus Pauling who, in 1962, noticed that the number of amino acid differences in hemoglobin between different lineages changes roughly linearly with time, as estimated from fossil evidence. They generalized this observation to assert that the rate of evolutionary change of any specified protein was approximately constant over time and over different lineages (known as the molecular clock hypothesis). The genetic equidistance phenomenon was first noted in 1963 by Emanuel Margoliash, who wrote: "It appears that the number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carpels
Gynoecium (; ; : gynoecia) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ''pistils'' and is typically surrounded by the pollen-producing reproductive organs, the stamens, collectively called the androecium. The gynoecium is often referred to as the "female" portion of the flower, although rather than directly producing female gametes (i.e. egg cells), the gynoecium produces megaspores, each of which develops into a female gametophyte which then produces egg cells. The term gynoecium is also used by botanists to refer to a cluster of archegonia and any associated modified leaves or stems present on a gametophyte shoot in mosses, liverworts, and hornworts. The corresponding terms for the male parts of those plants are clusters of antheridia within the androecium. Flowers that bear a gynoecium but no stamens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conifers
Conifers () are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All extant conifers are perennial woody plants with secondary growth. The majority are trees, though a few are shrubs. Examples include cedars, Douglas-firs, cypresses, firs, junipers, kauri, larches, pines, hemlocks, redwoods, spruces, and yews.Campbell, Reece, "Phylum Coniferophyta". ''Biology''. 7th ed. 2005. Print. p. 595. As of 2002, Pinophyta contained seven families, 60 to 65 genera, and more than 600 living species. Although the total number of species is relatively small, conifers are ecologically important. They are the dominant plants over large areas of land, most notably the taiga of the Northern Hemisphere, but also in similar cool climates in mountains further south. Boreal conifers have many wintertime adaptations. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
