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Swiss Hawkbit
''Leontodon pyrenaicus'' is a species of hawkbit found in the Alps, Pyrenees, Cantabrian Mountains, northern Apennines and northern parts of the Balkan Peninsula. It grows in meadows and on stony slopes from the tree line to over 3000 m, usually on acidic soils. It is perennial, and flowers from June to August. The stems of ''L. pyrenaicus'' are narrow, up to 30 cm long, with several scale-like leaves, and with a single flower head at the top. The leaves form a basal rosette, and are clearly stalked. The flower heads are 20–20 mm wide and bright yellow. ''L. pyrenaicus'' is divided into three allopatric subspecies which differ in their size and in the nature of the hairs on the bracts: *''L. pyrenaicus'' subsp. ''cantabricus'' lives in the Cantabrian Mountains *''L. pyrenaicus'' subsp. ''helveticus'' lives in the Alps, Apennines and Balkans *''L. pyrenaicus'' subsp. ''pyrenaicus'' lives in the Pyrenees A number of authors since 2006, based on molecular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antoine Gouan
Antoine Gouan (15 November 1733 – 1 September 1821) was a French naturalist who was a native of Montpellier. Gouan was a pioneer of Linnaean taxonomy in France. He began his studies in Toulouse, later returning to Montpellier, where he studied medicine at the University of Montpellier, university. Here he was a student of François Boissier de Sauvages de Lacroix (1706–1767), an ardent supporter of Carl Linnaeus. In August 1752, Gouan received his doctorate under the chairmanship of Antoine Magnol (1676–1759), and subsequently practiced medicine at Saint-Éloi Hospital in Montpellier. Soon afterwards his interest turned to natural history. In 1762 Gouan published a plant catalog of the botanical garden at Montpellier titled ''Hortus regius monspeliensis''. This publication was the first French botanical work that followed the binomial nomenclature of Linnaeus. In 1765 he penned ''Flora Monspeliaca'', and became ''titulaire'' at the Montpellier Academy. During this time perio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perennial Plant
A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also widely used to distinguish plants with little or no woody growth (secondary growth in girth) from trees and shrubs, which are also technically perennials. Perennialsespecially small flowering plantsthat grow and bloom over the spring and summer, die back every autumn and winter, and then return in the spring from their rootstock or other overwintering structure, are known as herbaceous perennials. However, depending on the rigours of local climate (temperature, moisture, organic content in the soil, microorganisms), a plant that is a perennial in its native habitat, or in a milder garden, may be treated by a gardener as an annual and planted out every year, from seed, from cuttings, or from divisions. Tomato vines, for example, live several y ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subgenus
In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the tiger cowry of the Indo-Pacific, ''Cypraea'' (''Cypraea'') ''tigris'' Linnaeus, which belongs to the subgenus ''Cypraea'' of the genus ''Cypraea''. However, it is not mandatory, or even customary, when giving the name of a species, to include the subgeneric name. In the International Code of Nomenclature for algae, fungi, and plants (ICNafp), the subgenus is one of the possible subdivisions of a genus. There is no limit to the number of divisions that are permitted within a genus by adding the prefix "sub-" or in other ways as long as no confusion can result. Article 4 The secondary ranks of section and series are subordinate to subgenus. An example is ''Banksia'' subg. ''Isostylis'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leontodon
''Leontodon'' is a genus of plants in the tribe Cichorieae within the family Asteraceae, commonly known as hawkbits. Their English name derives from the mediaeval belief that hawks ate the plant to improve their eyesight. Although originally only native to Eurasia and North Africa, some species have since become established in other countries, including the United States and New Zealand. Recent research has shown that the genus ''Leontodon'' in the traditional delimitation is polyphyletic. Therefore, the former ''Leontodon'' subgenus ''Oporinia'' was raised to generic level. According to the nomenclatural rules the name '' Scorzoneroides'' has priority at generic level and therefore, the members of ''Leontodon'' subgenus ''Oporinia'' were transferred to the re-erected genus ''Scorzoneroides''. Ecology Seeds of ''Leontodon'' species are an important food source for certain bird species. Uses In Crete, the species ''Leontodon tuberosus'' which is called ('), (') or (') has i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture. Typically, they also look different from the parts of the flower, such as the petals or sepals. A plant having bracts is referred to as bracteate or bracteolate, while one that lacks them is referred to as ebracteate and ebracteolate, without bracts. Variants Some bracts are brightly-coloured and serve the function of attracting pollinators, either together with the perianth or instead of it. Examples of this type of bract include those of ''Euphorbia pulcherrima'' (poinsettia) and ''Bougainvillea'': both of these have large colourful bracts surrounding much smaller, less colourful flowers. In grasses, each floret (flower) is enclosed in a pair of papery bracts, called the lemma (lower bract) and p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subspecies
In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species have subspecies, but for those that do there must be at least two. Subspecies is abbreviated subsp. or ssp. and the singular and plural forms are the same ("the subspecies is" or "the subspecies are"). In zoology, under the International Code of Zoological Nomenclature, the subspecies is the only taxonomic rank below that of species that can receive a name. In botany and mycology, under the International Code of Nomenclature for algae, fungi, and plants, other infraspecific ranks, such as variety, may be named. In bacteriology and virology, under standard bacterial nomenclature and virus nomenclature, there are recommendations but not strict requirements for recognizing other important infraspecific ranks. A taxonomist decides whether ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allopatric
Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with gene flow. Various geographic changes can arise such as the movement of continents, and the formation of mountains, islands, bodies of water, or glaciers. Human activity such as agriculture or developments can also change the distribution of species populations. These factors can substantially alter a region's geography, resulting in the separation of a species population into isolated subpopulations. The vicariant populations then undergo genetic changes as they become subjected to different selective pressures, experience genetic drift, and accumulate different mutations in the separated populations' gene pools. The barriers prevent the exchange of genetic information between t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rosette (botany)
In botany, a rosette is a circular arrangement of leaves or of structures resembling leaves. In flowering plants, rosettes usually sit near the soil. Their structure is an example of a modified stem in which the internode gaps between the leaves do not expand, so that all the leaves remain clustered tightly together and at a similar height. Some insects induce the development of galls that are leafy rosettes. In bryophytes and algae, a rosette results from the repeated branching of the thallus as the plant grows, resulting in a circular outline. Taxonomies Many plant families have varieties with rosette morphology; they are particularly common in Asteraceae (such as dandelions), Brassicaceae (such as cabbage), and Bromeliaceae. The fern '' Blechnum fluviatile'' or New Zealand Water Fern (''kiwikiwi'') is a rosette plant. Function in flowering plants Often, rosettes form in perennial plants whose upper foliage dies back with the remaining vegetation protecting the plant. Ano ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed on the axis of a plant. The modifications can involve the length and the nature of the internodes and the phyllotaxis, as well as variations in the proportions, compressions, swellings, adnations, connations and reduction of main and secondary axes. One can also define an inflorescence as the reproductive portion of a plant that bears a cluster of flowers in a specific pattern. The stem holding the whole inflorescence is called a peduncle. The major axis (incorrectly referred to as the main stem) above the peduncle bearing the flowers or secondary branches is called the rachis. The stalk of each flower in the inflorescence is called a pedicel. A flower that is not part of an inflorescence is called a solitary flower and its stalk is al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid
In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequence of database operations that satisfies the ACID properties (which can be perceived as a single logical operation on the data) is called a ''transaction''. For example, a transfer of funds from one bank account to another, even involving multiple changes such as debiting one account and crediting another, is a single transaction. In 1983, Andreas Reuter and Theo Härder coined the acronym ''ACID'', building on earlier work by Jim Gray who named atomicity, consistency, and durability, but not isolation, when characterizing the transaction concept. These four properties are the major guarantees of the transaction paradigm, which has influenced many aspects of development in database systems. According to Gray and Reuter, the IBM Informa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hawkbit
''Leontodon'' is a genus of plants in the tribe Cichorieae within the family Asteraceae, commonly known as hawkbits. Their English language, English name derives from the Middle Ages, mediaeval belief that hawks ate the plant to improve their eyesight. Although originally only native to Eurasia and North Africa, some species have since become established in other countries, including the United States and New Zealand. Recent research has shown that the genus ''Leontodon'' in the traditional delimitation is polyphyly, polyphyletic. Therefore, the former ''Leontodon'' subgenus ''Oporinia'' was raised to genus, generic level. According to the nomenclatural rules the name ''Scorzoneroides'' has priority at generic level and therefore, the members of ''Leontodon'' subgenus ''Oporinia'' were transferred to the re-erected genus ''Scorzoneroides''. Ecology Seeds of ''Leontodon'' species are an important food source for certain bird species. Uses In Crete, the species ''Leontodon tubero ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tree Line
The tree line is the edge of the habitat at which trees are capable of growing. It is found at high elevations and high latitudes. Beyond the tree line, trees cannot tolerate the environmental conditions (usually cold temperatures, extreme snowpack, or associated lack of available moisture). The tree line is sometimes distinguished from a lower timberline, which is the line below which trees form a forest with a closed Canopy (biology), canopy. At the tree line, tree growth is often sparse, stunted, and deformed by wind and cold. This is sometimes known as ''krummholz'' (German for "crooked wood"). The tree line often appears well-defined, but it can be a more gradual transition. Trees grow shorter and often at lower densities as they approach the tree line, above which they are unable to grow at all. Given a certain latitude, the tree line is approximately 300 to 1000 meters below the permanent snow line and roughly parallel to it. Causes Due to their vertical structure, tree ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
