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Felwort
''Swertia perennis'' is a species of flowering plant in the gentian family known by the common names felwort and star swertia. It is native to several regions of the northern hemisphere, including much of Eurasia and western North America. It is a plant of wetlands, particularly calcareous fens. It is common to abundant in many areas, but it is known to be negatively impacted by habitat fragmentation and other habitat destruction, and human activity has led to its extirpation from some areas where it was once common.Lienert, J., et al. (2002). Local extinctions of the wetland specialist ''Swertia perennis'' L. (Gentianaceae) in Switzerland: A revisitation study based on herbarium records. ''Biological Conservation'' 103-1 65-76. It is a perennial herb producing usually one erect stem growing 10 to 50 centimeters tall. The basal leaves are spoon-shaped with rounded tips, and leaves higher on the plant are widely lance-shaped or somewhat oval, with pointed tips. The inflorescenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swertia
''Swertia'' is a genus in the gentian family containing plants sometimes referred to as the felworts. Some species bear very showy purple and blue flowers. Many members of this genus have medicinal and cultural purposes. Plants of genus '' Frasera'' are sometimes considered part of this genus, sometimes as a separate genus, and sometimes as synonymous. Selected species According to Plants of the World Online, the genus has 165 species. Species in the genus ''Swertia'' include, but are not limited to: * '' Swertia angustifolia'' Buch.-Ham. ''ex'' D. Don * '' Swertia bimaculata'' (Siebold & Zucc.) C. B. Clarke ** ''Swertia bimaculata'' (Siebold & Zucc.) Hook. f. & Thoms. * '' Swertia calcicola'' Kerr. * '' Swertia chinensis'' (Griseb.) Franch. ** '' Swertia diluta'' (Turcz.) Benth. & Hook. f. * ''Swertia chirayita'' (Roxb. ''ex'' Fleming) H. Karst. ** ''Swertia chirata'' (Wall.) C. B. Clarke * '' Swertia ciliata'' (D. Don ''ex'' G. Don) B. L. Burtt. * '' Swertia cordata'' (Wall. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gentianaceae
Gentianaceae is a family of flowering plants of 105 genera and about 1600 species. Etymology The family takes its name from the genus ''Gentiana'', named after the Illyrian king Gentius. Distribution Distribution is cosmopolitan (species), cosmopolitan. Characteristics The family consists of trees, shrubs and herbs showing a wide range of colours and floral patterns. Flowers are actinomorphic and bisexual with fused sepals and petals. The stamens are attached to the inside of the petals (Stamens#Sexual reproduction in plants, epipetalous) and alternate with the corolla lobes. There is a glandular disk at the base of the gynoecium, and flowers have parietal placentation. The inflorescence is cymose, with simple or complex Cyme (botany), cymes. The fruits are dehiscent septicidal capsules splitting into two halves, rarely some species have a berry (botany), berry. Seeds are small with copiously oily endosperms and a straight embryo. The habit varies from small trees, pachycaul sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wetland
A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially in the soils. Wetlands form a transitional zone between waterbodies and dry lands, and are different from other terrestrial or aquatic ecosystems due to their vegetation's roots having adapted to oxygen-poor waterlogged soils. They are considered among the most biologically diverse of all ecosystems, serving as habitats to a wide range of aquatic and semi-aquatic plants and animals, with often improved water quality due to plant removal of excess nutrients such as nitrates and phosphorus. Wetlands exist on every continent, except Antarctica. The water in wetlands is either freshwater, brackish or saltwater. The main types of wetland are defined based on the dominant plants and the source of the water. For example, ''marshes'' ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone
Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science), crystal forms of calcium carbonate . Limestone forms when these minerals Precipitation (chemistry), precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly Dolomite (rock), dolomite, a closely related rock, which contains a high percentage of the mineral Dolomite (mine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Habitat Fragmentation
Habitat fragmentation describes the emergence of discontinuities (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay. Causes of habitat fragmentation include geological processes that slowly alter the layout of the physical environment (suspected of being one of the major causes of speciation), and human activity such as land conversion, which can alter the environment much faster and causes the extinction of many species. More specifically, habitat fragmentation is a process by which large and contiguous habitats get divided into smaller, isolated patches of habitats. Definition The term habitat fragmentation includes five discrete phenomena: * Reduction in the total area of the habitat * Decrease of the interior: edge ratio * Isolation of one habitat fragment from other areas of habitat * Breaking up of one patch of habitat into several smaller patches * Decrease in the average size of each patch of habit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Habitat Destruction
Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease in biodiversity and species numbers. Habitat destruction is in fact the leading cause of biodiversity loss and species extinction worldwide. Humans contribute to habitat destruction through the use of natural resources, agriculture, industrial production and urbanization (urban sprawl). Other activities include mining, logging and trawling. Environmental factors can contribute to habitat destruction more indirectly. Geological processes, climate change, introduction of invasive species, ecosystem nutrient depletion, water and noise pollution are some examples. Loss of habitat can be preceded by an initial habitat fragmentation. Fragmentation and loss of habitat have become one of the most important topics of research in ecology as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Local Extinction
Local extinction, also extirpation, is the termination of a species (or other taxon) in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with extinction, global extinctions. Local extinctions mark a change in the ecology of an area. It has sometimes been followed by a replacement of the species taken from other locations, such as with wolf reintroduction. Discussion Glacial period, Glaciation is one factor that leads to local extinction. This was the case during the Quaternary glaciation, Pleistocene glaciation event in North America. During this period, most of the native North American species of earthworm were killed in places covered by glaciation. This left them open for colonization by European earthworms brought over in soil from Europe. Species naturally become extinct from islands over time; this can be either local extinction if the species also occurs elsewhere, or in cases of endemism, island endemism, outright ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inflorescence
In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a main axis (Peduncle (botany), peduncle) and by the timing of its flowering (determinate and indeterminate). Morphology (biology), Morphologically, an inflorescence is the modified part of the Shoot (botany), shoot of spermatophyte, seed plants where flowers are formed on the axis of a plant. The modifications can involve the length and the nature of the internode (botany), 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. General characteristics Inflorescences are described by many different charact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panicle
In botany, a panicle is a much-branched inflorescence. (softcover ). Some authors distinguish it from a compound spike inflorescence, by requiring that the flowers (and fruit) be pedicellate (having a single stem per flower). The branches of a panicle are often racemes. A panicle may have determinate or indeterminate growth. This type of inflorescence is largely characteristic of grasses, such as oat and crabgrass, as well as other plants such as pistachio and mamoncillo. Botanists use the term paniculate in two ways: "having a true panicle inflorescence" as well as "having an inflorescence with the form but not necessarily the structure of a panicle". Corymb A corymb may have a paniculate branching structure, with the lower flowers having longer pedicels than the upper, thus giving a flattish top superficially resembling an umbel. Many species in the subfamily Amygdaloideae, such as hawthorns and rowans, produce their flowers in corymbs. up'' Sorbus glabrescens'' co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sepal
A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 Etymology The term ''sepalum'' was coined by Noël Martin Joseph de Necker in 1790, and derived . Collectively, the sepals are called the ''calyx'' (plural: calyces), the outermost Whorl (botany), whorl of parts that form a flower. The word ''calyx'' was adopted from the Latin ,Jackson, Benjamin, Daydon; A Glossary of Botanic Terms with their Derivation and Accent; Published by Gerald Duckworth & Co. London, 4th ed 1928 not to be confused with 'cup, goblet'. The Latin ''calyx'' is derived from Greek 'bud, calyx, husk, wrapping' ( Sanskrit 'bud'), while is derived from Greek 'cup, goblet'; both words have been used interchangeably in botanical Latin. Description The term ''tepal'' is usually applied when the parts of the perianth are difficult to distinguish, e. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stamen
The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament and an anther which contains sporangium, microsporangia. Most commonly, anthers are two-lobed (each lobe is termed a locule) and are attached to the filament either at the base or in the middle area of the anther. The sterile (i.e. nonreproductive) tissue between the lobes is called the Connective (botany), connective, an extension of the filament containing conducting strands. It can be seen as an extension on the dorsal side of the anther. A pollen grain develops from a microspore in the microsporangium and contains the male gametophyte. The size of anthers differs greatly, from a tiny fraction of a millimeter in ''Wolfia'' spp up to five inches (13 centimeters) in ''Canna iridiflora'' and ''Strelitzia nicolai''. The stamens in a flower ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gynoecium
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 (botany), whorl of a flower; it consists of (one or more) ''#Pistil, pistils'' and is typically surrounded by the pollen-producing plant reproductive morphology, 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, Marchantiophyta, liverworts, and hornworts. The corresponding terms for the male parts of those plants are clusters of antheridiu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
