There are about 380,000 known species of plants, of which the majority, some 260,000, produce seeds. They range in size from single cells to the tallest trees. Green plants provide a substantial proportion of the world's molecular oxygen; the sugars they create supply the energy for most of Earth's ecosystems and other organisms, including animals, either consume plants directly or rely on organisms which do so. (Full article...)
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Banksia prionotes, commonly known as acorn banksia or orange banksia, is a species of shrub or tree of the genus Banksia in the family Proteaceae. It is native to the southwest of Western Australia and can reach up to 10 m (33 ft) in height. It can be much smaller in more exposed areas or in the north of its range. This species has serrated, dull green leaves and large, bright flower spikes, initially white before opening to a bright orange. Its common name arises from the partly opened inflorescence, which is shaped like an acorn. The tree is a popular garden plant and also of importance to the cut flower industry.
Banksia prionotes was first described in 1840 by English botanist John Lindley, probably from material collected by James Drummond the previous year. There are no recognised varieties, although it has been known to hybridise with Banksia hookeriana. Widely distributed in south-west Western Australia, B. prionotes is found from Shark Bay (25° S) in the north, south as far as Kojonup (33°50′S). It grows exclusively in sandy soils, and is usually the dominant plant in scrubland or low woodland. Pollinated by birds, it provides food for a wide array of vertebrate and invertebrate animals in the autumn and winter months. It is an important source of food for honeyeaters (Meliphagidae), and is critical to their survival in the Avon Wheatbelt region, where it is the only nectar-producing plant in flower at some times of the year. (Full article...)
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Adenanthos obovatus, commonly known as basket flower (which usually refers to Centaurea, though), or, jugflower, is a shrub of the plantfamilyProteaceaeendemic to Southwest Australia. Described by French naturalist Jacques Labillardière in 1805, it had first been collected by Archibald Menzies in 1791. Within the genus Adenanthos, it lies in the sectionEurylaema and is most closely related to A. barbiger. A. obovatus has hybridized with A. detmoldii to produce the hybrid A. × pamela. Several common names allude to the prominent red flowers of the species. It grows as a many-stemmed spreading bush up to 1 m (3.3 ft) high, and about 1.5 m (4.9 ft) across, with fine bright green foliage. Made up of single red flowers, the inflorescences appear from April to December, and peak in spring (August to October).
The shrub grows on sandy soils in seasonally wet lowland areas as well as hills and dunes. It regenerates after bushfire by resprouting from its underground lignotuber. Pollinators include honeyeaters, particularly the western spinebill, which can access the nectar with its long curved bill, and the silvereye, which punctures the flower tube. The most commonly cultivated Adenanthos species in Australia, it has a long flowering period and attracts honeyeaters to the garden. It is harvested for the cut flower industry. (Full article...)
Banksia blechnifolia is a species of flowering plant in the genusBanksia found in Western Australia. It was first described by Victorian state botanist Ferdinand von Mueller in 1864, and no subspecies are recognised. It gained its specific name as its leaves are reminiscent of a fern (Blechnum). B. blechnifolia is one of several closely related species that grow as prostrate shrubs, with horizontal stems and leathery, upright leaves. The red-brown flower spikes, known as inflorescences, are up to 20 centimetres (8 in) high and appear from September to November in the Australian spring. As the spikes age, each turns grey and develops as many as 25 woody seed pods, known as follicles.
Insects such as bees, wasps, ants and flies pollinate the flowers. Found in sandy soils in the south coastal region of Western Australia in the vicinity of Lake King, B. blechnifolia is non-lignotuberous, regenerating by seed after bushfire. The plant adapts readily to cultivation, growing in well-drained sandy soils in sunny locations. It is suitable for rockeries and as a groundcover. (Full article...)
A cabbage generally weighs between 500 and 1,000 grams (1 and 2 lb). Smooth-leafed, firm-headed green cabbages are the most common, with smooth-leafed purple cabbages and crinkle-leafed savoy cabbages of both colours being rarer. Under conditions of long sunny days, such as those found at high northern latitudes in summer, cabbages can grow quite large. , the heaviest cabbage was 62.71 kilograms (138 lb 4 oz). Cabbage heads are generally picked during the first year of the plant's life cycle, but plants intended for seed are allowed to grow a second year and must be kept separate from other cole crops to prevent cross-pollination. Cabbage is prone to several nutrient deficiencies, as well as to multiple pests, and bacterial and fungal diseases. (Full article...)
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Persoonia lanceolata, commonly known as lance-leaf geebung, is a shrub native to New South Wales in eastern Australia. It reaches 3 m (10 ft) in height and has smooth grey bark and bright green foliage. Its small yellow flowers grow on racemes and appear in the austral summer and autumn (January to April), followed by green fleshy fruits (known as drupes) which ripen the following spring (September to October). Within the genus Persoonia, P. lanceolata belongs to the lanceolata group of 58 closely related species. It interbreeds with several other species found in its range.
The species is usually found in dry sclerophyll forest on sandstone-based nutrient-deficient soil. It has adapted to a fire-prone environment; plants lost in bushfires can regenerate through a ground-stored seed bank. Seedlings mostly germinate within two years of fires. Several species of native bee of the genus Leioproctus pollinate the flowers. Swamp wallabies are a main consumer of its fruit, and the seeds are spread in wallaby faeces. Its lifespan ranges from 25 to 60 years, though difficulties in propagation have seen low cultivation rates. (Full article...)
Banksia serrata, commonly known as the saw banksia, the old man banksia, the saw-tooth banksia or the red honeysuckle and as wiriyagan by the Cadigal people, is a species of woody shrub or tree of the genus Banksia, in the family Proteaceae. Native to the east coast of Australia, it is found from Queensland to Victoria with outlying populations on Tasmania and Flinders Island. Commonly growing as a gnarled tree up to 16 m (50 ft) in height, it can be much smaller in more exposed areas. This Banksia species has wrinkled grey bark, shiny dark green serrated leaves and large yellow or greyish-yellow flower spikes appearing over summer. The flower spikes, or inflorescences, turn grey as they age and pollinated flowers develop into large, grey, woody seed pods called follicles.
B. serrata is one of the four original Banksia species collected by Sir Joseph Banks in 1770, and one of four species published in 1782 as part of Carolus Linnaeus the Younger's original description of the genus. There are no recognised varieties, although it is closely related to Banksia aemula. Throughout its range, it grows exclusively in sandy soil, and is usually the dominant plant in scrubland or low woodland. B. serrata is pollinated by and provides food for a wide array of vertebrate and invertebrate animals in the autumn and winter months, and is an important source of food for honeyeaters. It is a common plant of parks and gardens. (Full article...)
Banksia oblongifolia, commonly known as the fern-leaved, dwarf or rusty banksia, is a species in the plant genusBanksia. Found along the eastern coast of Australia from Wollongong, New South Wales in the south to Rockhampton, Queensland in the north, it generally grows in sandy soils in heath, open forest or swamp margins and wet areas. A many-stemmed shrub up to 3 m (9.8 ft) high, it has leathery serrated leaves and rusty-coloured new growth. The yellow flower spikes, known as inflorescences, most commonly appear in autumn and early winter. Up to 80 follicles, or seed pods, develop on the spikes after flowering. Banksia oblongifolia resprouts from its woody lignotuber after bushfires, and the seed pods open and release seed when burnt, the seed germinating and growing on burnt ground. Some plants grow between fires from seed shed spontaneously.
Spanish botanist Antonio José CavanillesdescribedB. oblongifolia in 1800, though it was known as Banksia aspleniifolia in New South Wales for many years. However, the latter name, originally coined by Richard Anthony Salisbury, proved invalid, and Banksia oblongifolia has been universally adopted as the correct scientific name since 1981. Two varieties were recognised in 1987, but these have not been generally accepted. A wide array of mammals, birds, and invertebrates visit the inflorescences. Though easily grown as a garden plant, it is not commonly seen in horticulture. (Full article...)
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Grevillea juniperina, commonly known as juniper- or juniper-leaf grevillea or prickly spider-flower, is a plant of the family Proteaceae native to eastern New South Wales and southeastern Queensland in Australia. Scottish botanist Robert Brown described the species in 1810, and seven subspecies are recognised. One subspecies, G. j. juniperina, is restricted to Western Sydney and environs and is threatened by loss of habitat and housing development.
A small, prickly-leaved shrub between 0.2–3 m (0.66–9.84 ft) high, G. juniperina generally grows on clay-based or alluvial soils in eucalyptwoodland. The flower heads, known as inflorescences, appear from winter to early summer and are red, orange or yellow. Birds visit and pollinate the flowers. Grevillea juniperina plants are killed by bushfire, regenerating afterwards from seed. Grevillea juniperina adapts readily to cultivation and has been important in horticulture as it is the parent of many popular garden hybrids. (Full article...)
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Alloxylon pinnatum, known as Dorrigo waratah, is a tree of the family Proteaceae found in warm-temperate rainforest of south-east Queensland and northern New South Wales in eastern Australia. It has shiny green leaves that are either pinnate (lobed) and up to 30 cm (12 in) long, or lanceolate (spear-shaped) and up to 15 cm (5.9 in) long. The prominent pinkish-red flower heads, known as inflorescences, appear in spring and summer; these are made up of 50 to 140 individual flowers arranged in corymb or raceme. These are followed by rectangular woody seed pods, which bear two rows of winged seeds.
Known for many years as Oreocallis pinnata, it was transferred to the new genus Alloxylon by Peter Weston and Mike Crisp in 1991. This genus contains the four species previously classified in Oreocallis that are found in Australasia. Its terminal globular flowers indicate that the species is pollinated by birds. Classified as near threatened under the Queensland Nature Conservation Act 1992, the Dorrigo waratah has proven difficult to keep alive in cultivation. (Full article...)
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'Blue Spire' cultivar
Salvia yangii, previously known as Perovskia atriplicifolia (/pəˈrɒvskiəætrɪplɪsɪˈfoʊliə/), and commonly called Russian sage, is a flowering herbaceousperennial plant and subshrub. Although not previously a member of Salvia, the genus widely known as sage, since 2017 it has been included within them. It has an upright habit, typically reaching 0.5–1.2 metres (1+1⁄2–4 feet) tall, with square stems and gray-green leaves that yield a distinctive odor when crushed. It is best known for its flowers. Its flowering season extends from mid-summer to late October, with blue to violet blossoms arranged into showy, branched panicles.
It is native to the steppes and hills of southwestern and central Asia. Successful over a wide range of climate and soil conditions, it has since become popular and widely planted. Several cultivars have been developed, differing primarily in leaf shape and overall height; 'Blue Spire' is the most common. This variation has been widely used in gardens and landscaping. S. yangii was the Perennial Plant Association's 1995 Plant of the Year, and the 'Blue Spire' cultivar received the Award of Garden Merit from the Royal Horticultural Society. (Full article...)
Johann George Adam Forster, also known as Georg Forster (German pronunciation:[ˈɡeːɔʁkˈfɔʁstɐ], 27 November 1754 – 10 January 1794), was a German geographer, naturalist, ethnologist, travel writer, journalist and revolutionary. At an early age, he accompanied his father, Johann Reinhold Forster, on several scientific expeditions, including James Cook's second voyage to the Pacific. His report of that journey, A Voyage Round the World, contributed significantly to the ethnology of the people of Polynesia and remains a respected work. As a result of the report, Forster, who was admitted to the Royal Society at the early age of twenty-two, came to be considered one of the founders of modern scientific travel literature.
After returning to continental Europe, Forster turned toward academia. He taught natural history at the Collegium Carolinum in the Ottoneum, Kassel (1778–84), and later at the Academy of Vilna (Vilnius University) (1784–87). In 1788, he became head librarian at the University of Mainz. Most of his scientific work during this time consisted of essays on botany and ethnology, but he also prefaced and translated many books about travel and exploration, including a German translation of Cook's diaries. (Full article...)
Its aromatic, "labrusca" flavor is similar to that of Concord, but mellowed by the mild, sweet taste from Thompson Seedless. Thomcord grows well in hot, dry climates, ripens between late July and mid-August, and tolerates powdery mildew. It is a productive variety, yielding an average of 15.1 kg (33 lb) of grapes per vine, but has produced as much as 30 to 32 kg (66 to 71 lb) per vine in grower trials. The berries weigh between 2.72 and 3.38 g (0.096 and 0.119 oz) and have a medium-thick, blue-black skin that adheres to the fruit, unlike Concord, which has a thick skin that can slip off the pulp easily. The aborted seeds in the fruit body are relatively small, but larger than those in Thompson Seedless. (Full article...)
While at the bookshop, he was offered a position as a librarian at the Royal Horticultural Society in London (1933–1952). From there he moved to the Natural History Museum as a scientific officer in the botany department (1952–1976). After his retirement, he continued working there, writing, and serving on a number of professional bodies related to his work, including the Linnean Society, of which he became president. He also taught botany at Cambridge University as a visiting professor (1977–1983). (Full article...)
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The flora of Madagascar consists of more than 12,000 species of plants, as well as a poorly known number of fungi and algae. Around 83% of Madagascar's vascular plants are found only on the island. These endemics include five plant families, 85% of the over 900 orchid species, around 200 species of palms, and such emblematic species as the traveller's tree, six species of baobab and the Madagascar periwinkle. The high degree of endemism is due to Madagascar's long isolation following its separation from the African and Indian landmasses in the Mesozoic, 150–160 and 84–91 million years ago, respectively. However, few plant lineages remain from the ancient Gondwanan flora; most extant plant groups immigrated via across-ocean dispersal well after continental break-up.
After its continental separation, Madagascar probably experienced a dry period, and tropical rainforest expanded only later in the Oligocene to Miocene when rainfall increased. Today, humid forests, including the lowland forests, are mainly found on the eastern plateau where abundant rainfall from the Indian Ocean is captured by an escarpment. A large part of the central highlands, in the sub-humid forests ecoregion, is today dominated by grasslands. They are widely seen as result of human landscape transformation but some may be more ancient. Grassland occurs in a mosaic with woodland and bushland, including tapia forest, and hard-leaved thickets on the high mountains. Dry forest and succulent woodland are found in the drier western part and grade into the unique spiny thicket in the southwest, where rainfall is lowest and the wet season shortest. Mangroves occur on the west coast, and a variety of wetland habitats with an adapted flora are found across the island. (Full article...)
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Lambertia formosa, commonly known as mountain devil, is a shrub of the family Proteaceae, endemic to New South Wales, Australia. First described in 1798 by English botanist James Edward Smith, it is the type species of the small genus Lambertia. It is generally found in heathland or open forest, growing in sandstone-based soils. It grows as a multistemmed shrub to around 2 m (7 ft) with a woody base known as a lignotuber, from which it regrows after bushfire. It has stiff narrow leaves, and the pink to red flowerheads, made up of seven individual tubular flowers, generally appear in spring and summer. It gains its common name from the horned woody follicles, which were used to make small devil-figures.
The flowers hold profuse amounts of nectar and are pollinated by honeyeaters. Although L. formosa is uncommon in cultivation, it is straightforward to grow in soils with good drainage and a partly shaded to sunny aspect. It is readily propagated by seed. Unlike all other members of the genus Lambertia, L. formosa is greatly resistant to the soil pathogen Phytophthora cinnamomi. (Full article...)
Ornamental bulbous plants, often called ornamental bulbs or just bulbs in gardening and horticulture, are herbaceousperennials grown for ornamental purposes, which have underground or near ground storage organs. Botanists distinguish between true bulbs, corms, rhizomes, tubers and tuberous roots, any of which may be termed "bulbs" in horticulture. Bulb species usually lose their upper parts during adverse conditions such as summer drought and heat or winter cold. The bulb's storage organs contain moisture and nutrients that are used to survive these adverse conditions in a dormant state. When conditions become favourable the reserves sustain a new growth cycle. In addition, bulbs permit vegetative or asexual multiplication in these species. Ornamental bulbs are used in parks and gardens and as cut flowers. (Full article...)
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Aquatic plants are plants that have adapted to living in aquatic environments (saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that grows in or near water and is either emergent, submergent, or floating. In lakes and rivers, macrophytes provide cover for fish, substrate for aquaticinvertebrates, produce oxygen, and act as food for some fish and wildlife.
Macrophytes are primary producers and are the basis of the food web for many organisms. They have a significant effect on soil chemistry and light levels as they slow down the flow of water and capture pollutants and trap sediments. Excess sediment will settle into the benthos aided by the reduction of flow rates caused by the presence of plant stems, leaves and roots. Some plants have the capability of absorbing pollutants into their tissue. Seaweeds are multicellular marinealgae and, although their ecological impact is similar to other larger water plants, they are not typically referred to as macrophytes. (Full article...)
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The Eastern Agricultural Complex in the woodlands of eastern North America was one of about 10 independent centers of plant domestication in the pre-historic world. Incipient agriculture dates back to about 5300 BCE. By about 1800 BCE the Native Americans of the woodlands were cultivating several species of food plants, thus beginning a transition from a hunter-gatherer economy to agriculture. After 200 BCE when maize from Mexico was introduced to the Eastern Woodlands, the Native Americans of the eastern United States and adjacent Canada slowly changed from growing local indigenous plants to a maize-based agricultural economy. The cultivation of local indigenous plants other than squash and sunflower declined and was eventually abandoned. The formerly domesticated plants returned to their wild forms.
A banana is an elongated, edible fruit – botanically a berry – produced by several kinds of large herbaceousflowering plants in the genusMusa. In some countries, cooking bananas are called plantains, distinguishing them from dessert bananas. The fruit is variable in size, color, and firmness, but is usually elongated and curved, with soft flesh rich in starch covered with a rind, which may have a variety of colors when ripe. The fruits grow upward in clusters near the top of the plant. Almost all modern edible seedless (parthenocarp) bananas come from two wild species – Musa acuminata and Musa balbisiana. Most cultivated bananas are M. acuminata, M. balbisiana, or hybrids of the two.
Musa species are native to tropical Indomalaya and Australia; they were probably domesticated in New Guinea. They are grown in 135 countries, primarily for their fruit, and to a lesser extent to make banana paper and textiles, while some are grown as ornamental plants. The world's largest producers of bananas in 2022 were India and China, which together accounted for approximately 26% of total production. Bananas are eaten raw or cooked in recipes varying from curries to banana chips, fritters, fruit preserves, or simply baked or steamed. (Full article...)
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Fruit tree propagation is usually carried out vegetatively (non-sexually) by grafting or budding a desired variety onto a suitable rootstock.
Perennial plants can be propagated either by sexual or vegetative means. Sexual reproduction begins when a male germ cell (pollen) from one flower fertilises a female germ cell (ovule, incipient seed) of the same species, initiating the development of a fruit containing seeds. Each seed, when germinated, can grow to become a new specimen tree. However, the new tree inherits characteristics of both its parents, and it will not grow true to the variety of either parent from which it came. That is, it will be a fresh individual with an unpredictable combination of characteristics of its own. Although this is desirable in terms of producing novel combinations from the richness of the gene pool of the two parent plants (such sexual recombination is the source of new cultivars), only rarely will the resulting new fruit tree be directly useful or attractive to the tastes of humankind. Most new plants will have characteristics that lie somewhere between those of the two parents. (Full article...)
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Evolutionary developmental biology (evo-devo) is the study of developmental programs and patterns from an evolutionary perspective. It seeks to understand the various influences shaping the form and nature of life on the planet. Evo-devo arose as a separate branch of science rather recently. An early sign of this occurred in 1999.
Plant ecology is a subdiscipline of ecology that studies the distribution and abundance of plants, the effects of environmental factors upon the abundance of plants, and the interactions among plants and between plants and other organisms. Examples of these are the distribution of temperate deciduous forests in North America, the effects of drought or flooding upon plant survival, and competition among desert plants for water, or effects of herds of grazing animals upon the composition of grasslands.
A global overview of the Earth's major vegetation types is provided by O.W. Archibold. He recognizes 11 major vegetation types: tropical forests, tropical savannas, arid regions (deserts), Mediterranean ecosystems, temperate forest ecosystems, temperate grasslands, coniferous forests, tundra (both polar and high mountain), terrestrial wetlands, freshwater ecosystems and coastal/marine systems. This breadth of topics shows the complexity of plant ecology, since it includes plants from floating single-celled algae up to large canopy forming trees. (Full article...)
Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particular have long propagated using the movements of humans and other animals in a symbiotic relationship that is the means for seed dispersal for the one group and nutrition for the other; humans and many other animals have become dependent on fruits as a source of food. Consequently, fruits account for a substantial fraction of the world's agricultural output, and some (such as the apple and the pomegranate) have acquired extensive cultural and symbolic meanings. (Full article...)
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Carnivorous plants are plants that derive some or most of their nutrients from trapping and consuming animals or protozoans, typically insects and other arthropods, and occasionally small mammals and birds. They still generate all of their energy from photosynthesis. They have adapted to grow in waterlogged sunny places where the soil is thin or poor in nutrients, especially nitrogen, such as acidic bogs. They can be found on all continents except Antarctica, as well as many Pacific islands. In 1875, Charles Darwin published Insectivorous Plants, the first treatise to recognize the significance of carnivory in plants, describing years of painstaking research.
True carnivory is believed to have evolved independently at least 12 times in five different orders of flowering plants, and is represented by more than a dozen genera. This classification includes at least 583 species that attract, trap, and kill prey, absorbing the resulting available nutrients. Venus flytrap (Dionaea muscipula), pitcher plant (Cephalotus follicularis), and bladderwort (Utricularia gibba) can be seen as exemplars of key traits genetically associated with carnivory: trap leaf development, prey digestion, and nutrient absorption. (Full article...)
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Genetically modified crops (GM crops) are plants used in agriculture, the DNA of which has been modified using genetic engineering methods. Plant genomes can be engineered by physical methods or by use of Agrobacterium for the delivery of sequences hosted in T-DNA binary vectors. In most cases, the aim is to introduce a new trait to the plant which does not occur naturally in the species. Examples in food crops include resistance to certain pests, diseases, environmental conditions, reduction of spoilage, resistance to chemical treatments (e.g. resistance to a herbicide), or improving the nutrient profile of the crop. Examples in non-food crops include production of pharmaceutical agents, biofuels, and other industrially useful goods, as well as for bioremediation.
Farmers have widely adopted GM technology. Acreage increased from 1.7 million hectares in 1996 to 185.1 million hectares in 2016, some 12% of global cropland. As of 2016, major crop (soybean, maize, canola and cotton) traits consist of herbicide tolerance (95.9 million hectares) insect resistance (25.2 million hectares), or both (58.5 million hectares). In 2015, 53.6 million ha of Genetically modified maize were under cultivation (almost 1/3 of the maize crop). GM maize outperformed its predecessors: yield was 5.6 to 24.5% higher with less mycotoxins (−28.8%), fumonisin (−30.6%) and thricotecens (−36.5%). Non-target organisms were unaffected, except for lower populations some parasitoid wasps due to decreased populations of their pest host European corn borer; European corn borer is a target of Lepidoptera active Bt maize. Biogeochemical parameters such as lignin content did not vary, while biomass decomposition was higher. (Full article...)
Bernard de Jussieu was born in Lyon. He took a medical degree at Montpellier and began practice in 1720, but finding the work uncongenial he gladly accepted his brother's invitation to Paris in 1722, when he succeeded Sebastien Vaillant (1669–1722) as sub-demonstrator of plants in the Jardin des Plantes. In 1725 he brought out a new edition of Joseph Pitton de Tournefort's Histoire des plantes qui naissent aux environs de Paris, 2 vols., which was afterwards translated into English by John Martyn, the original work being incomplete. In the same year he was admitted into the French Academy of Sciences, and communicated several papers to that body. (Full article...)
The name "ragweed" is derived from "ragged" + "weed," coming from the ragged appearance of the plant's leaves. Other common names include bursages and burrobrushes. The genus name is from the Greekambrosia, meaning "food or drink of immortality". (Full article...)
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Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophytes during the process of their movement from the stamens to the pistil of flowering plants, or from the male cone to the female cone of gymnosperms. If pollen lands on a compatible pistil or female cone, it germinates, producing a pollen tube that transfers the sperm to the ovule containing the female gametophyte. Individual pollen grains are small enough to require magnification to see detail. The study of pollen is called palynology and is highly useful in paleoecology, paleontology, archaeology, and forensics. Pollen in plants is used for transferring haploid male genetic material from the anther of a single flower to the stigma of another in cross-pollination. In a case of self-pollination, this process takes place from the anther of a flower to the stigma of the same flower.
Pollen is infrequently used as food and food supplement. Because of agricultural practices, it is often contaminated by agricultural pesticides. (Full article...)
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Pollination of fruit trees is required to produce seeds with surrounding fruit. It is the process of moving pollen from the anther to the stigma, either in the same flower or in another flower. Some tree species, including many fruit trees, do not produce fruit from self-pollination, so pollinizer trees are planted in orchards.
The pollination process requires a carrier for the pollen, which can be animal, wind, or human intervention (by hand-pollination or by using a pollen sprayer). Cross pollination produces seeds with a different genetic makeup from the parent plants; such seeds may be created deliberately as part of a selective breeding program for fruit trees with desired attributes. Trees that are cross-pollinated or pollinated via an insect pollinator produce more fruit than trees with flowers that just self-pollinate. In fruit trees, bees are an essential part of the pollination process for the formation of fruit. (Full article...)
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Tropical vegetation is any vegetation in tropicallatitudes. Plant life that occurs in climates that are warm year-round is in general more biologically diverse that in other latitudes. Some tropical areas may receive abundant rain the whole year round, but others have long dry seasons which last several months and may vary in length and intensity with geographic location. These seasonal droughts have great impact on the vegetation, such as in the Madagascar spiny forests.
Rainforest vegetation is categorized by five layers. The top layer being the upper tree layer. Here you will find the largest and widest trees in all the forest. These trees tend to have very large canopy's so they can be fully exposed to sunlight. A layer below that is the middle tree layer. Here you will find more compact trees and vegetation. These trees tend to be more skinny as they are trying to gain any sunlight they can. The third layer is the lower tree area. These trees tend to be around five to ten meters high and tightly compacted. The trees found in the third layer are young trees trying to grow into the larger canopy trees. The fourth layer is the shrub layer beneath the tree canopy. This layer is mainly populated by sapling trees, shrubs, and seedlings. The fifth and final layer is the herb layer which is the forest floor. The forest floor is mainly bare except for various plants, mosses, and ferns. The forest floor is much more dense than above because of little sunlight and air movement. (Full article...)
Cirsium vulgare is a species of thistle in the plant family Asteraceae. Native to Europe and Western Asia, it has become naturalised in North America, Africa and Australia, and is an invasive weed in some areas. It is a ruderal species, able to colonise bare ground, but also persists well on pasture as its thorny leaves and stems make it unpalatable to most grazing animals. The flowers are rich in nectar, attracting bees and butterflies, and the seeds are a favourite with goldfinches, linnets and greenfinches. The downy pappus, which assists in wind dispersal of the seeds, is used by birds as nest-lining material.
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A cultivar is a kind of cultivated plant that people have selected for desired traits and which retains those traits when propagated. Methods used to propagate cultivars include division, root and stem cuttings, offsets, grafting, tissue culture, or carefully controlled seed production. Most cultivars arise from deliberate human manipulation, but some originate from wild plants that have distinctive characteristics. Cultivar names are chosen according to rules of the International Code of Nomenclature for Cultivated Plants (ICNCP), and not all cultivated plants qualify as cultivars. Horticulturists generally believe the word cultivar was coined as a term meaning "cultivated variety".
Popular ornamental plants like roses, camellias, daffodils, rhododendrons, and azaleas are commonly cultivars produced by breeding and selection or as sports, for floral colour or size, plant form, or other desirable characteristics. Similarly, the world's agricultural food crops are almost exclusively cultivars that have been selected for characters such as improved yield, flavour, and resistance to disease, and very few wild plants are now used as food sources. Trees used in forestry are also special selections grown for their enhanced quality and yield of timber. (Full article...)
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The Webster Sycamore (alternatively known as the Webster Springs Sycamore and the Big Sycamore Tree) was an American sycamore (Platanus occidentalis) in the U.S. state of West Virginia. Long recognized for its size, the Webster Sycamore was the largest living American sycamore tree in West Virginia until its felling in 2010. The tree stood approximately 4.5 miles (7.2 km) east of Webster Springs in Webster County, in a moist flood plain along the banks of the Back Fork Elk River, a tributary stream of the Elk River.
The Webster Sycamore reached a tree height measurement of 112 feet (34 m), a tree crown measurement of 90 feet (27 m), and a circumference of 25.75 feet (7.85 m) at breast height. In 1955, the American Forests Association declared the tree the largest of its species in the United States. It only held the title for three weeks, before the association identified a larger American sycamore in Maryland. Despite losing its national title, the sycamore remained the largest American sycamore in West Virginia. Following a 1963 survey of large trees in West Virginia, the Webster Sycamore was named the second-largest tree after a white oak (Quercus alba) in Randolph County. (Full article...)
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Domestication is a multi-generational mutualistic relationship in which an animal species, such as humans or leafcutter ants, takes over control and care of another species, such as sheep or fungi, so as to obtain from them a steady supply of resources, such as meat, milk, or labor. The process is gradual and geographically diffuse, based on trial and error.
The first animal to be domesticated by humans was the dog, as a commensal, at least 15,000 years ago. Other animals including goats, sheep, and cows were domesticated starting around 11,000 years ago. Among birds, the chicken was first domesticated in East Asia, seemingly for cockfighting, some 7,000 years ago. The horse came under domestication around 5,500 years ago in central Asia as a working animal. Among invertebrates, the silkworm and the western honey bee were domesticated over 5,000 years ago for silk and honey, respectively. (Full article...)
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Portrait of Elfving, 1870s
Fredrik Emil Volmar Elfving (9 December 1854 – 21 June 1942) was a Swedish-speaking Finnish botanist, plant physiologist, and university administrator. During his university training, he frequently traveled abroad to learn new scientific methods and techniques from other prominent European scientists. Although his earliest publications dealt with phytogeography and phycology (particularly the green algae known as the desmids), his most notable research was in plant physiology. Early in his career, he published seminal work on the flow of water through the stems of woody plants, and investigated the phenomenon of transversely geotropic plant organs. In contrast to his works on plant physiology, his later experiments and views on lichens, which he himself considered his most important work, was far less favourably received.
Elfving became a Professor of botany at the University of Helsinki in 1892, a position he held until his retirement in 1926. A lively and enthusiastic teacher, Elfving revolutionized the teaching of botany at the university by introducing laboratory courses that emphasized the study of plant physiology, rather than taxonomy, as had been the tradition. During his time as professor, Elfving wrote many historical papers about scientific societies, and biographies of Scandinavian scientists. He wrote the books Tärkeimmät viljelyskasvit ("The Most Important Crops") and the Kasvitieteen oppikirja ("Botanical Textbook"), which were widely used as textbooks. Elfving has had several taxa named after him. (Full article...)
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Hypericum androsaemum, the type species of the section
The members of Androsaemum are deciduous shrubs of medium size. They are characterized by their lack of hairs and by not having small dark glands. Plants possess clusters of many yellow flowers, each of which has several dozen male reproductive stamens, as well as a seed capsule that regularly dry out and split open. Extracts taken from the species have diverse profiles of essential oils. These are made up mostly of organic compounds consisting entirely of hydrogen and carbon, but they also sometimes contain high amounts of other chemicals. (Full article...)
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Sweet potato cultivation in Polynesia as a crop began around 1000 AD in central Polynesia. The plant became a common food across the region, especially in Hawaii, Easter Island and New Zealand, where it became a staple food. By the 17th century in central Polynesia, traditional cultivars were being replaced with hardier and larger varieties from the Americas (a process which began later in New Zealand, in the early 19th century). Many traditional cultivars are still grown across Polynesia, but they are rare and are not widely commercially grown.
It is unknown how sweet potato began to be cultivated in the Pacific, but the current scholarly consensus is that the presence of sweet potato in Polynesia is evidence of Polynesian contact with South America. However, some genetic studies of traditional cultivars suggest that sweet potato was first dispersed to Polynesia before human settlement. (Full article...)
An evergreenperennial, it originates from the Arabian Peninsula, but also grows wild in tropical, semi-tropical, and arid climates around the world. It is cultivated for commercial products, mainly as a topical treatment used over centuries. The species is attractive for decorative purposes, and succeeds indoors as a potted plant. (Full article...)
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In mathematics, the three-gap theorem, three-distance theorem, or Steinhaus conjecture states that if one places n points on a circle, at angles of θ, 2θ, 3θ, ... from the starting point, then there will be at most three distinct distances between pairs of points in adjacent positions around the circle. When there are three distances, the largest of the three always equals the sum of the other two. Unless θ is a rational multiple of π, there will also be at least two distinct distances.
This result was conjectured by Hugo Steinhaus, and proved in the 1950s by Vera T. Sós, János Surányi [hu], and Stanisław Świerczkowski; more proofs were added by others later. Applications of the three-gap theorem include the study of plant growth and musical tuning systems, and the theory of light reflection within a mirrored square. (Full article...)
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A portrait of Christian Ramsay, beside a watercolour of a flower and a bird
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are usable as lumber or plants above a specified height. In wider definitions, the taller palms, tree ferns, bananas, and bamboos are also trees.
Trees are not a monophyletic taxonomic group but consist of a wide variety of plant species that have independently evolved a trunk and branches as a way to tower above other plants to compete for sunlight. The majority of tree species are angiosperms or hardwoods; of the rest, many are gymnosperms or softwoods. Trees tend to be long-lived, some reaching several thousand years old. Trees have been in existence for 370 million years. It is estimated that there are around three trillion mature trees in the world. (Full article...)
Elke Mackenzie (11 September 1911 – 18 January 1990), born Ivan Mackenzie Lamb, was a British polar explorer and botanist who specialized in the field of lichenology. Beginning her education in Edinburgh, Scotland, Mackenzie later pursued botany at Edinburgh University, earning a Bachelor of Science degree in 1933 and a Doctor of Science in 1942. In the two years she was involved in Operation Tabarin, a covert World War II mission to Antarctica, she identified and documented many lichen species, several of them previously unknown to science.
Utricularia inflata, commonly known as the swollen bladderwort, inflated bladderwort, or large floating bladderwort, is a large suspended aquatic carnivorous plant that belongs to the genusUtricularia. It is a perennial that is native to the southeastern coastal plains of the United States. It has often been confused with U. radiata, which is similar but smaller than U. inflata. Since 1980, U. inflata has been reported to exist in locations beyond its traditional range, such as the Adirondack Mountains in New York, southeastern Massachusetts, and in Washington State. Studies on the populations in the Adirondacks suggest that an introduction of U. inflata to a location where it naturalizes can lead to altered sediment chemistry by reducing the net primary productivity of native species. It is also listed by the state of Washington as a problematic species because of the dense mat-forming habit of this aquatic Utricularia. It is one of the few carnivorous plants that can be invasive. (Full article...)
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Characteres generum plantarum (complete title Characteres generum plantarum, quas in Itinere ad Insulas Maris Australis, Collegerunt, Descripserunt, Delinearunt, annis MDCCLXXII-MDCCLXXV Joannes Reinoldus Forster et Georgius Forster, "Characteristics of the types of plants collected, described, and delineated during a voyage to islands of the South Seas, in the years 1772–1775 by Johann Reinhold Forster and Georg Forster") is a 1775/1776 book by Johann Reinhold Forster and Georg Forster about the botanical discoveries they made during the second voyage of James Cook.
The book contains 78 plates, the majority of which depict dissections of flowers at natural size. The book introduced 94 binomial names from 75 genera, of which 43 are still the accepted names today. Many plant genera were named after friends or patrons of the Forsters. The book was published in a folio and a quarto edition and translated into German in 1779. It is an important book as the earliest publication of names and descriptions of the native species of New Zealand. (Full article...)
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Mereschkowski c. 1885
Konstantin Sergeevich Mereschkowski (Russian: Константи́н Серге́евич Мережко́вский, IPA:[mʲɪrʲɪˈʂkofskʲɪj]; 4 August 1855 [O.S. 23 July] – 9 January 1921) was a Russianbiologist and botanist, active mainly around Kazan, whose research on lichens led him to propose the theory of symbiogenesis – that larger, more complexcells (of eukaryotes) evolved from the symbiotic relationship between less complex ones. He presented this theory in 1910, in his work, The Theory of Two Plasms as the Basis of Symbiogenesis, a New Study of the Origins of Organisms, although the fundamentals of the idea had already appeared in his earlier 1905 work, The nature and origins of chromatophores in the plant kingdom. (Full article...)
Image 6Thale cress, Arabidopsis thaliana, the first plant to have its genome sequenced, remains the most important model organism. (from Botany)
Image 7Transverse section of a fossil stem of the Devonian vascular plant Rhynia gwynne-vaughani (from Botany)
Image 8A late Siluriansporangium, artificially colored. Green: A spore tetrad. Blue: A spore bearing a trilete mark – the Y-shaped scar. The spores are about 30–35 μm across. (from Evolutionary history of plants)
Image 9Five of the key areas of study within plant physiology (from Botany)
Image 10Structure of a plant cell (from Plant cell)
Image 13Echeveria glauca in a Connecticut greenhouse. Botany uses Latin names for identification; here, the specific name glauca means blue. (from Botany)
Image 18Leaf lamina. The megaphyllous leaf architecture arose multiple times in different plant lineages (from Evolutionary history of plants)
Image 19Structure of Azadirachtin, a terpenoid produced by the Neem plant, which helps ward off microbes and insects. Many secondary metabolites have complex structures (from Evolutionary history of plants)
Image 20The fruit of Myristica fragrans, a species native to Indonesia, is the source of two valuable spices, the red aril (mace) enclosing the dark brown nutmeg. (from Botany)
Image 26A nineteenth-century illustration showing the morphology of the roots, stems, leaves and flowers of the rice plant Oryza sativa (from Botany)
Image 27The Linnaean Garden of Linnaeus' residence in Uppsala, Sweden, was planted according to his Systema sexuale. (from Botany)
Image 28The trunk of early tree fern Psaronius, showing internal structure. The top of the plant would have been to the left of the image (from Evolutionary history of plants)
Image 291 An oat coleoptile with the sun overhead. Auxin (pink) is evenly distributed in its tip. 2 With the sun at an angle and only shining on one side of the shoot, auxin moves to the opposite side and stimulates cell elongation there. 3 and 4 Extra growth on that side causes the shoot to bend towards the sun. (from Botany)
Image 33The Devonian marks the beginning of extensive land colonization by plants, which – through their effects on erosion and sedimentation – brought about significant climatic change. (from Evolutionary history of plants)
Image 35The evolution of syncarps. a: sporangia borne at tips of leaf b: Leaf curls up to protect sporangia c: leaf curls to form enclosed roll d: grouping of three rolls into a syncarp (from Evolutionary history of plants)
Image 36This is an electron micrograph of the epidermal cells of a Brassica chinensis leaf. The stomates are also visible. (from Plant cell)
Image 37A banded tube from the Late Silurian/Early Devonian. The bands are difficult to see on this specimen, as an opaque carbonaceous coating conceals much of the tube. Bands are just visible in places on the left half of the image. Scale bar: 20 μm (from Evolutionary history of plants)