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 eat plants directly or rely on organisms which do so. (Full article...)
Banksia grossa is a species of shrub in the familyProteaceae and is endemic to Southwest Australia. It is one of fourteen species of banksia of the series Abietinae, all of which bear predominantly cylindrical or oval inflorescences. Collected in 1965, it was first formally described in 1981 by Alex George. Its thick leaves and large seeds distinguish it from other members of the Abietinae, and are the basis of its species name.
Found in sand or sand over laterite among heath between Eneabba and Badgingarra in Western Australia, the species grows as a many-stemmed shrub to 1 m (3.3 ft) high with narrow leaves and oval brownish flower spikes up to 10 cm (4 in) high, composed of hundreds of individual flowers. Flowering occurs throughout the cooler months of March to September. Flower spikes develop woody follicles which bear the seeds. After bushfire, Banksia grossa regenerates from its woody lignotuber; bushfires also stimulate the release of seeds, which germinate after disturbance. Visitors to (and likely pollinators of) inflorescences include insects and a nocturnal mammal, the white-tailed dunnart. (Full article...)
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Acacia pycnantha, most commonly known as the golden wattle, is a tree of the family Fabaceae. It grows to a height of 8 metres (26 feet) and has phyllodes (flattened leaf stalks) instead of true leaves. The profuse fragrant, golden flowers appear in late winter and spring, followed by long seed pods. Explorer Thomas Mitchell collected the type specimen, from which George Bentham wrote the species description in 1842. The species is native to southeastern Australia as an understorey plant in eucalyptus forest. Plants are cross-pollinated by several species of honeyeater and thornbill, which visit nectaries on the phyllodes and brush against flowers, transferring pollen between them.
A. pycnantha has become a weed in areas of Australia, as well as in Africa and Eurasia. Its bark produces more tannin than any other wattle species, resulting in its commercial cultivation for production of this compound. It has been widely grown as an ornamental garden plant and for cut flower production. A. pycnantha was made the official floral emblem of Australia in 1988, and has been featured on the country's postal stamps. (Full article...)
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Adiantum viridimontanum growing in a dunite roadcut
Adiantum viridimontanum, commonly known as Green Mountain maidenhair fern, is a fern found only in outcrops of serpentine rock in New England and Eastern Canada. The leaf blade is cut into finger-like segments, themselves once-divided, which are borne on the outer side of a curved, dark, glossy rachis. These finger-like segments are not individual leaves, but parts of a single compound leaf. The "fingers" may be drooping or erect, depending on whether the individual fern grows in shade or sunlight. Spores are borne under false indusia at the edge of the subdivisions of the leaf, a characteristic unique to the genus Adiantum.
Until 1991, A. viridimontanum was grouped with the western maidenhair fern, A. aleuticum, which grows both in western North America and as a disjunct on serpentine outcrops in eastern North America. At one time, A. aleuticum itself was classified as a variety (A. pedatum var. aleuticum) of the northern maidenhair fern, A. pedatum. However, after several years of study, botanist Cathy Paris recognized that A. aleuticum was a distinct species, and that some of the specimens that had been attributed to that taxon (group of organisms) were a third, hybrid species intermediate between A. pedatum and A. aleuticum. She named the new species A. viridimontanum for the site of its discovery in the Green Mountains in Vermont; it has since been located in Quebec and in one site in coastal Maine. (Full article...)
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Dracophyllum fiordense, commonly known as the Fiordland grass tree, is a species of tree or shrub in the heath family, Ericaceae. It is endemic to the South Island of New Zealand. It reaches a height of 1.5–5.0 metres (5–16 feet) and has tufts of long green leaves at the ends of its branches. Each leaf has a distinctive curled spiral tip. D. fiordense has a pyramid-shaped inflorescence (flower spike) hidden under each clump of leaves, with between 113 and 120 pink flowers on each spike, and later reddish-brown dry fruit; both are around just 2 by 2 mm. It inhabits shrubland, lowland and subalpine forests, and tussock grassland of mountain slopes, gullies, and ridges. Its range covers two main areas: one in Fiordland National Park, and one in Aoraki / Mount Cook and Westland National Parks.
D. fiordense was first described by the New Zealand naturalist Walter Oliver in 1928 and placed by him in the subgenus Dracophyllum. A cladistic analysis using genetic sequencing was published in 2010, which revealed that D. fiordense is closely related to D. menziesii as Oliver had hypothesised. Its conservation status was assessed in 2017 as "Declining". The kākāpō, a flightless bird, feeds on the bases of the leaves by making careful incisions in new shoots. D. fiordense is likely pollinated by insects and its seeds are later dispersed by the wind. (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...)
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Banksia ilicifolia, commonly known as holly-leaved banksia, is a tree in the familyProteaceae. Endemic to southwest Western Australia, it belongs to Banksia subg. Isostylis, a subgenus of three closely related Banksia species with inflorescences that are dome-shaped heads rather than characteristic Banksia flower spikes. It is generally a tree up to 10 metres (33 ft) tall with a columnar or irregular habit. Both the scientific and common names arise from the similarity of its foliage to that of the English holly Ilex aquifolium; the glossy green leaves generally have very prickly serrated margins, although some plants lack toothed leaves. The inflorescences are initially yellow but become red-tinged with maturity; this acts as a signal to alert birds that the flowers have opened and nectar is available.
Robert Brown described Banksia ilicifolia in 1810. Although Banksia ilicifolia is variable in growth form, with low coastal shrubby forms on the south coast near Albany, there are no recognised varieties as such. Distributed broadly, the species is restricted to sandy soils. Unlike its close relatives which are killed by fire and repopulate from seed, Banksia ilicifolia regenerates after bushfire by regrowing from epicormic buds under its bark. It is rarely cultivated. (Full article...)
Ficus obliqua, commonly known as the small-leaved fig, is a tree in the family Moraceae, native to eastern Australia, New Guinea, eastern Indonesia to Sulawesi and islands in the southwestern Pacific Ocean. Previously known for many years as Ficus eugenioides, it is a banyan of the genus Ficus, which contains around 750 species worldwide in warm climates, including the edible fig (Ficus carica). Beginning life as a seedling, which grows on other plants (epiphyte) or on rocks (lithophyte), F. obliqua can grow to 60 m (200 ft) high and nearly as wide with a pale grey buttressed trunk, and glossy green leaves.
Xerochrysum bracteatum, commonly known as the golden everlasting or strawflower, is a flowering plant in the family Asteraceae native to Australia. Described by Étienne Pierre Ventenat in 1803, it was known as Helichrysum bracteatum for many years before being transferred to a new genus Xerochrysum in 1990. It is an annual up to 1 m (3.3 ft) tall with green or grey leafy foliage. Golden yellow or white flower heads are produced from spring to autumn; their distinctive feature is the papery bracts that resemble petals. The species is widespread, growing in a variety of habitats across the country, from rainforest margins to deserts and subalpine areas. The golden everlasting serves as food for various larvae of lepidopterans (butterflies and moths), and adult butterflies, hoverflies, native bees, small beetles, and grasshoppers visit the flower heads.
The golden everlasting has proven very adaptable to cultivation. It was propagated and developed in Germany in the 1850s, and annual cultivars in a host of colour forms from white to bronze to purple flowers became available. Many of these are still sold in mixed seed packs. In Australia, many cultivars are perennial shrubs, which have become popular garden plants. Sturdier, long-stemmed forms are used commercially in the cut flower industry. (Full article...)
Banksia sessilis, commonly known as parrot bush, is a species of shrub or tree in the plantgenusBanksia of the family Proteaceae. It had been known as Dryandra sessilis until 2007, when the genus Dryandra was sunk into Banksia. The Noongar peoples know the plant as budjan or butyak. Widespread throughout southwestWestern Australia, it is found on sandy soils over laterite or limestone, often as an understorey plant in open forest, woodland or shrubland. Encountered as a shrub or small tree up to 6 m (20 ft) in height, it has prickly dark green leaves and dome-shaped cream-yellow flowerheads. Flowering from winter through to late spring, it provides a key source of food—both the nectar and the insects it attracts—for honeyeaters in the cooler months, and species diversity is reduced in areas where there is little or no parrot bush occurring. Several species of honeyeater, some species of native bee, and the European honey bee seek out and consume the nectar, while the long-billed black cockatoo and Australian ringneck eat the seed. The life cycle of Banksia sessilis is adapted to regular bushfires. Killed by fire and regenerating by seed afterwards, each shrub generally produces many flowerheads and a massive amount of seed. It can recolonise disturbed areas, and may grow in thickets.
Banksia sessilis has a somewhat complicated taxonomic history. It was collected from King George Sound in 1801 and described by Robert Brown in 1810 as Dryandra floribunda, a name by which it was known for many years. However, Joseph Knight had published the name Josephia sessilis in 1809, which had precedence due to its earlier date, and the specific name was formalised in 1924. Four varieties are recognised. It is a prickly plant with little apparent horticultural potential; none of the varieties are commonly seen in cultivation. A profuse producer of nectar, B. sessilis is valuable to the beekeeping industry. (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...)
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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...)
Two subspecies—P.t.terminalis and P.t.recurva—are recognised; both are found on well-drained acidic soils in sclerophyll forests, and P.t.terminalis is also found on granite outcrops. Although similar in appearance, they differ in leaf length and curvature. Both have a restricted range, with P.t.terminalis found in an area of under 100 square kilometres (39 square miles; 25,000 acres). (Full article...)
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Banksia verticillata, commonly known as granite banksia or Albany banksia, is a species of shrub or (rarely) tree of the genus Banksia in the family Proteaceae. It is native to the southwest of Western Australia and can reach up to 3 m (10 ft) in height. It can grow taller to 5 m (16 ft) in sheltered areas, and much smaller in more exposed areas. This species has elliptic green leaves and large, bright golden yellow inflorescences or flower spikes, appearing in summer and autumn. The New Holland honeyeater (Phylidonyris novaehollandiae) is the most prominent pollinator, although several other species of honeyeater, as well as bees, visit the flower spikes.
A declared vulnerable species, it occurs in two disjunct populations on granite outcrops along the south coast of Western Australia, with the main population near Albany and a smaller population near Walpole, and is threatened by dieback (Phytophthora cinnamomi) and aerial canker (Zythiostroma). B. verticillata is killed by bushfire and new plants regenerate from seed afterwards. Populations take over a decade to produce seed and fire intervals of greater than twenty years are needed to allow the canopy seed bank to accumulate. (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...)
White tea, yellow tea, green tea, oolong, dark tea (which includes pu-erh tea) and black tea are all harvested from one of two major varieties grown today, C. sinensis var. sinensis and C. s. var. assamica, but are processed differently to attain varying levels of oxidation with black tea being the most oxidized and white being the least. Kukicha (twig tea) is also harvested from C. sinensis, but uses twigs and stems rather than leaves. (Full article...)
The common commercial variety is called the California Blackeye; it is pale-colored with a prominent black spot. The American South has countless varieties, many of them heirloom, that vary in size from the small lady peas to very large ones. The color of the eye may be black, brown, red, pink, or green. All the peas are green when freshly shelled and brown or buff when dried. A popular variation of the black-eyed pea is the purple hull pea or mud-in-your-eye pea; it is usually green with a prominent purple or pink spot. The currently accepted botanical name for the black-eyed pea is Vigna unguiculata subsp. unguiculata, although previously it was classified in the genusPhaseolus. Vigna unguiculata subsp. dekindtiana is the wild relative and Vigna unguiculata subsp. sesquipedalis is the related asparagus bean. Other beans of somewhat similar appearance, such as the frijol ojo de cabra (goat's-eye bean) of northern Mexico, are sometimes incorrectly called black-eyed peas, and vice versa. (Full article...)
Breadfruit (Artocarpus altilis) is a species of flowering tree in the mulberry and jackfruit family (Moraceae) believed to be a domesticated descendant of Artocarpus camansi originating in New Guinea, the Maluku Islands, and the Philippines. It was initially spread to Oceania via the Austronesian expansion. It was further spread to other tropical regions of the world during the Colonial Era. British and French navigators introduced a few Polynesian seedless varieties to Caribbean islands during the late 18th century. Today it is grown in 90 countries throughout South and Southeast Asia, the Pacific Ocean, the Caribbean, Central America and Africa. Its name is derived from the texture of the moderately ripe fruit when cooked, similar to freshly baked bread and having a potato-like flavor.
The trees have been widely planted in tropical regions, including lowland Central America, northern South America, and the Caribbean. In addition to the fruit serving as a staple food in many cultures, the light, sturdy timber of breadfruit has been used for outriggers, ships, and houses in the tropics. (Full article...)
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Three soil scientists examining a farm land sample Plant nutrition is the study of the chemical elements and compounds necessary for plant growth and reproduction, plant metabolism and their external supply. In its absence the plant is unable to complete a normal life cycle, or that the element is part of some essential plant constituent or metabolite. This is in accordance with Justus von Liebig'slaw of the minimum. The total essential plant nutrients include seventeen different elements: carbon, oxygen and hydrogen which are absorbed from the air, whereas other nutrients including nitrogen are typically obtained from the soil (exceptions include some parasitic or carnivorous plants).
Plants must obtain the following mineral nutrients from their growing medium:
An ethylene signal transduction pathway. Ethylene permeates the cell membrane and binds to a gasoreceptor on the endoplasmic reticulum. The gasoreceptor releases the repressed EIN2. This then activates a signal transduction pathway which activates regulatory genes that eventually trigger an ethylene response. The activated DNA is transcribed into mRNA which is then translated into a functional enzyme that is used for ethylene biosynthesis. Ethylene (CH 2=CH 2) is an unsaturatedhydrocarbon gas (alkene) acting as a naturally occurring plant hormone. It is the simplest alkene gas and is the first gas known to act as a hormone. It acts at trace levels throughout the life of the plant by stimulating or regulating the ripening of fruit, the opening of flowers, the abscission (or shedding) of leaves and, in aquatic and semi-aquatic species, promoting the 'escape' from submergence by means of rapid elongation of stems or leaves. This escape response is particularly important in rice farming. Commercial fruit-ripening rooms use "catalytic generators" to make ethylene gas from a liquid supply of ethanol. Typically, a gassing level of 500 to 2,000 ppm is used, for 24 to 48 hours. Care must be taken to control carbon dioxide levels in ripening rooms when gassing, as high temperature ripening (20 °C; 68 °F) has been seen to produce CO2 levels of 10% in 24 hours. (Full article...)
Some species are shrubs, trees (such as teak), or, rarely, vines. Many members of the family are widely cultivated, not only for their aromatic qualities, but also their ease of cultivation, since they are readily propagated by stem cuttings. Besides those grown for their edible leaves, some are grown for decorative foliage. Others are grown for seed, such as Salvia hispanica (chia), or for their edible tubers, such as Plectranthus edulis, P. esculentus, P. rotundifolius, and Stachys affinis (Chinese artichoke). Many are also grown ornamentally, notably coleus, Plectranthus, and many Salvia species and hybrids. (Full article...)
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Cotyledon from a Judas-tree (Cercis siliquastrum, a dicot) seedling A cotyledon (/ˌkɒtɪˈliːdən/KOT-ill-EE-dən; from Latincotyledon; from κοτυληδών (kotulēdṓn) "a cavity, small cup, any cup-shaped hollow", gen. κοτυληδόνος (kotulēdónos), from κοτύλη (kotýlē)'cup, bowl') is a "seed leaf" – a significant part of the embryo within the seed of a plant – and is formally defined as "the embryonic leaf in seed-bearing plants, one or more of which are the first to appear from a germinating seed." Botanists use the number of cotyledons present as one characteristic to classify the flowering plants (angiosperms): species with one cotyledon are called monocotyledonous ("monocots"); plants with two embryonic leaves are termed dicotyledonous ("dicots"). Be it noted that many orchids with minute seeds have no identifiable cotyledon, and are regarded as acotyledons. The Dodders (Cuscuta spp) also lack cotyledons.
In the case of dicot seedlings whose cotyledons are photosynthetic, the cotyledons are functionally similar to leaves. However, true leaves and cotyledons are developmentally distinct. Cotyledons form during embryogenesis, along with the root and shoot meristems, and are therefore present in the seed prior to germination. True leaves, however, form post-embryonically (i.e. after germination) from the shoot apical meristem, which generates subsequent aerial portions of the plant. (Full article...)
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Bee pollinating a flower Entomophily or insect pollination is a form of pollination whereby pollen of plants, especially but not only of flowering plants, is distributed by insects. Flowers pollinated by insects typically advertise themselves with bright colours, sometimes with conspicuous patterns (honey guides) leading to rewards of pollen and nectar; they may also have an attractive scent which in some cases mimics insect pheromones. Insect pollinators such as bees have adaptations for their role, such as lapping or sucking mouthparts to take in nectar, and in some species also pollen baskets on their hind legs. This required the coevolution of insects and flowering plants in the development of pollination behaviour by the insects and pollination mechanisms by the flowers, benefiting both groups. Both the size and the density of a population are known to affect pollination and subsequent reproductive performance. (Full article...)
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Zosterophyllum species fossils; left: with coiled (circinate) branch tips, right: with sporangium
The zosterophylls are a group of extinct land plants that first appeared in the Silurian period. The taxon was first established by Banks in 1968 as the subdivisionZosterophyllophytina; they have since also been treated as the divisionZosterophyllophyta or Zosterophyta and the class or plesionZosterophyllopsida or Zosteropsida. They were among the first vascular plants in the fossil record, and had a world-wide distribution. They were probably stem-grouplycophytes, forming a sister group to the ancestors of the living lycophytes. By the late Silurian (late Ludlovian, about 420 million years ago) a diverse assemblage of species existed, examples of which have been found fossilised in what is now Bathurst Island in ArcticCanada. (Full article...)
Monocotyledons are contrasted with the dicotyledons, which have two cotyledons. Unlike the monocots however, the dicots are not monophyletic and the two cotyledons are instead the ancestral characteristic of all flowering plants. Botanists now classify dicots into the eudicots ("true dicots") and several basal lineages from which the monocots emerged. (Full article...)
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Rosa Morning Jewel (1968) James Cocker and Sons is a nursery business located in Aberdeen, Scotland. Founded in 1841 (184 years ago) (1841) by James Cocker, the company has been owned by the Cocker family for five generations. During the last seventy years, the nursery has introduced more than 100 new rose varieties and holds Royal Warrants from Queen Elizabeth, the Queen Mother, and the Prince of Wales. James Cocker & Sons is best known for creating the hybrid tea rose, 'Silver Jubilee', the popular rose named in honour of the Queen's 25 years reign. The rose was developed by Alec Cocker, and introduced by his wife, Anne Cocker, after Alec's death in 1977. Anne continued to breed roses and manage the company until she was in her eighties. She won multiple horticultural awards and was internationally recognized for her work. (Full article...)
Citrus is native to South Asia, East Asia, Southeast Asia, Melanesia, and Australia. Indigenous people in these areas have used and domesticated various species since ancient times. Its cultivation first spread into Micronesia and Polynesia through the Austronesian expansion (c. 3000–1500 BCE). Later, it was spread to the Middle East and the Mediterranean (c. 1200 BCE) via the incense trade route, and from Europe to the Americas. (Full article...)
Opuntia, commonly called the prickly pear cactus, is a genus of flowering plants in the cactusfamily Cactaceae, many known for their flavorful fruit and showy flowers. Cacti are well-adapted to aridity; however, they are still vulnerable to alterations in precipitation and temperature driven by climate change. Prickly pear alone is more commonly used to refer exclusively to the fruit, but may also be used for the plant itself; in addition, other names given to the plant and its specific parts include tuna (fruit), sabra, sabbar, nopal (pads, plural nopales) from the Nahuatl word nōpalli, nostle (fruit) from the Nahuatl word nōchtli, and paddle cactus. The genus is named for the Ancient Greek city of Opus, where, according to Theophrastus, an edible plant grew and could be propagated by rooting its leaves. The most common culinary species is the "Barbary fig" (Opuntia ficus-indica). (Full article...)
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The diversity of leaves A leaf (pl.: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, flower, and fruit collectively form the shoot system. In most leaves, the primary photosynthetictissue is the palisade mesophyll and is located on the upper side of the blade or lamina of the leaf, but in some species, including the mature foliage of Eucalyptus, palisade mesophyll is present on both sides and the leaves are said to be isobilateral. The leaf is an integral part of the stem system, and most leaves are flattened and have distinct upper (adaxial) and lower (abaxial) surfaces that differ in color, hairiness, the number of stomata (pores that intake and output gases), the amount and structure of epicuticular wax, and other features. Leaves are mostly green in color due to the presence of a compound called chlorophyll which is essential for photosynthesis as it absorbs light energy from the Sun. A leaf with lighter-colored or white patches or edges is called a variegated leaf.
Leaves can have many different shapes, sizes, textures and colors. The broad, flat leaves with complex venation of flowering plants are known as megaphylls and the species that bear them (the majority) as broad-leaved or megaphyllous plants, which also include acrogymnosperms and ferns. In the lycopods, with different evolutionary origins, the leaves are simple (with only a single vein) and are known as microphylls. Some leaves, such as bulb scales, are not above ground. In many aquatic species, the leaves are submerged in water. Succulent plants often have thick juicy leaves, but some leaves are without major photosynthetic function and may be dead at maturity, as in some cataphylls and spines. Furthermore, several kinds of leaf-like structures found in vascular plants are not totally homologous with them. Examples include flattened plant stems called phylloclades and cladodes, and flattened leaf stems called phyllodes which differ from leaves both in their structure and origin. Some structures of non-vascular plants look and function much like leaves. Examples include the phyllids of mosses and liverworts. (Full article...)
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Ethnobotanist Richard Evans Schultes at work in the Amazon in the 1940s Ethnobotany is an interdisciplinary field at the interface of natural and social sciences that studies the relationships between humans and plants. It focuses on traditional knowledge of how plants are used, managed, and perceived in human societies. Ethnobotany integrates knowledge from botany, anthropology, ecology, and chemistry to study plant-related customs across cultures. Researchers in this field document and analyze how different societies use local flora for various purposes, including medicine, food, religious use, intoxicants, building materials, fuels and clothing. Richard Evans Schultes, often referred to as the "father of ethnobotany", provided an early definition of the discipline:Since Schultes' time, ethnobotany has evolved from primarily documenting traditional plant knowledge to applying this information in modern contexts, particularly in pharmaceutical development. The field now addresses complex issues such as intellectual property rights and equitable benefit-sharing arrangements arising from the use of traditional knowledge. (Full article...)
Eucalyptus gomphocephala, known as tuart, is a species of tree and is one of the six forest giants of Southwest Australia.The trees usually grow to a height of 10 to 40 m (33 to 131 ft) and mostly have a single stem, but can have multiple stems under some conditions. The crown can be as wide as 25 metres (82 ft). It has rough box-like bark over the length of the trunk and larger branches. The glossy light-green to green adult leaves are arranged alternately and have an oval to lanceolate or falcate shape, and have a leaf blade that is 90 to 180 millimetres (3.5 to 7.1 in) long and 1.5 to 3 cm (0.59 to 1.18 in) wide. The tree flowers between January and April with white to cream inflorescences that form in the leaf axils and are not branched. The fruits that follow have an obconic to upside-down bell shape. (Full article...)
Hypericum minutum is a species of flowering plant in the St John's wort family Hypericaceae. It is a small perennial herb that grows in tufts. It has slender and brittle stems, flowers in clusters of one to three, yellow petals with black and amber glands, few stamens, and a seed capsule with narrow grooves. H. minutum is closely related to H. huber-morathii and H. sechmenii and resembles a smaller form of the latter plant. The plant is endemic to Turkey, and is found among limestone rocks in a limited region of southwestern Anatolia. Originally excluded from a comprehensive monograph of Hypericum, the species' placement within the genus is unclear. It has been placed in both section Adenosepalum and section Origanifolium. (Full article...)
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James Kirkham Ramsbottom (11 October 1891 – 9 February 1925) was an English botanist. He became interested in the field after he was recommended to pursue an outdoor career for his health. After a short period at the Chelsea Physic Garden, Ramsbottom studied at the RHS Garden Wisley. Coming first in their diploma examinations, Ramsbottom became a research student at the Royal Horticultural Society (RHS) in 1913. He studied leaf blotch disease in irises and became assistant editor of Gardeners' Magazine.
In March 1916, Ramsbottom was appointed to lead a study into a mysterious disease, known as "rootless disease", that was affecting daffodil (Narcissus) bulbs and threatened the destruction of the nascent daffodil-growing industry. The disease had been known for around 30 years, but its cause was not certain, although a number of pests and fungi were suspected. By April 1917 Ramsbottom was able to prove the disease was caused by an infestation of the Ditylenchus dipsaci nematode and developed a treatment involving dipping affected bulbs in hot water. The treatment saved the daffodil-growing industry and remains the basis for modern-day treatment of the disease. Ramsbottom continued to work on the treatment and was invited to lecture in the United States. He died in New York by either falling or jumping from a 19th-storey window in the Hotel McAlpin. (Full article...)
Attalea is a large genus of palms native to Mexico, the Caribbean, Central and South America. This pinnately-leaved, non-spiny genus includes both small palms lacking an aboveground stem and large trees. The genus has a complicated taxonomic history, and has often been split into four or five genera based on differences in the male flowers. Since the genera can only be distinguished on the basis of their male flowers, the existence of intermediate flower types and the existence of hybrids between different genera has been used as an argument for keeping them all in the same genus. This has been supported by recent molecular phylogenies.
Between 29 and 67 species are recognised in the genus, with estimates of as many as 100. Incomplete herbarium collections make it difficult to determine whether certain groups represent single species, or groups of similar species. Attalea species have a long history of human use, and include economically important sources of palm oil and fibre. Many species are fire tolerant and thrive in disturbed habitats. Their seeds are animal dispersed, including some which are thought to have been adapted for dispersal by now-extinct Pleistocene megafauna. (Full article...)
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Coscinodon lawianus is a species of moss in the family Grimmiaceae endemic to East Antarctica. It is one of only two species of moss found only in continental Antarctica (alongside Bryum bharatiense), out of 23 species found on the continent. It is found on exposed rocks on nunataks and oases scattered across the region, stretching from Queen Maud Land to Princess Elizabeth Land. Initially described as part of the genus Grimmia, it was reclassified into Coscinodon by Polish bryologist Ryszard Ochyra in 2004, owing to similarities with several South American species. C. lawianus is likely a remnant of the Neogene flora of Antarctica which survived the rampant glaciation and cooling of the continent on remote rocky outcrops. (Full article...)
Chili peppers, also spelled chile or chilli (from Classical Nahuatlchīlli[ˈt͡ʃiːlːi]ⓘ), are varieties of berry-fruit plants from the genusCapsicum, which are members of the nightshade family Solanaceae, cultivated for their pungency. Chili peppers are widely used in many cuisines as a spice to add "heat" to dishes. Capsaicin and the related capsaicinoids give chili peppers their intensity when ingested or applied topically. Chili peppers exhibit a range of heat and flavors. This diversity is the reason behind the availability of different types of chili powder, each offering its own taste and heat level.
Chili peppers originated in Central or South America and were first cultivated in Mexico. European explorers brought chili peppers back to the Old World in the late 16th century as part of the Columbian Exchange, which led to the cultivation of multiple varieties across the world for food and traditional medicine. Five Capsicum species have been widely cultivated: annuum, baccatum, chinense, frutescens, and pubescens. (Full article...)
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A display of commercially-grown bulbs, including red and yellow cultivars.
An onion (Allium cepa L., from Latincepa meaning "onion"), also known as the bulb onion or common onion, is a vegetable that is the most widely cultivated species of the genus Allium. The shallot is a botanical variety of the onion which was classified as a separate species until 2011. The onion's close relatives include garlic, scallion, leek, and chives.
The genus contains several other species variously called onions and cultivated for food, such as the Japanese bunching onion Allium fistulosum, the tree onionAllium × proliferum, and the Canada onion Allium canadense. The name wild onion is applied to a number of Allium species, but A. cepa is exclusively known from cultivation. Its ancestral wild original form is not known, although escapes from cultivation have become established in some regions. The onion is most frequently a biennial or a perennial plant, but is usually treated as an annual and harvested in its first growing season. (Full article...)
Flowering plants are plants that bear flowers and fruits, and form the cladeAngiospermae (/ˌændʒiəˈspərmiː/). The term 'angiosperm' is derived from the Greek words ἀγγεῖον / angeion ('container, vessel') and σπέρμα / sperma ('seed'), meaning that the seeds are enclosed within a fruit. The group was formerly called Magnoliophyta.
John Hunter Thomas (March 26, 1928 – July 20, 1999) was an American botanist, professor of biological sciences at Stanford University, curator and director of the Dudley Herbarium, and joint curator at the California Academy of Sciences. He was known for his study of plants in the Sonoran Desert, the Santa Cruz Mountains, and the Alaska North Slope, and for his history of botanical exploration in Washington, Oregon, and California. His doctoral research on the plants of the Santa Cruz Mountains was published as a guide to the vascular plants of coastal, central California, and was recognized as a standard reference work for regional flora. It was used for decades as teaching material for courses in systematic botany and the ecology of vascular plants at Stanford. Thomas helped establish the Jasper Ridge Biological Preserve and was a primary contributor to what later became the Jasper Ridge Oakmead Herbarium (JROH). In total, Thomas collected more than 20,000 plant specimens for herbaria throughout his career. (Full article...)
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Orto botanico di Pisa, the first university botanic garden in Europe, established in 1544 under botanist Luca Ghini, operated by the University of Pisa. It was relocated in 1563 and again in 1591.
A botanical garden or botanic garden is a garden with a documented collection of living plants for the purpose of scientific research, conservation, display, and education. It is their mandate as a botanical garden that plants are labelled with their botanical names. It may contain specialist plant collections such as cacti and other succulent plants, herb gardens, plants from particular parts of the world, and so on; there may be glasshouses or shadehouses, again with special collections such as tropicalplants, alpine plants, or other exotic plants that are not native to that region.
Most are at least partly open to the public, and may offer guided tours, public programming such as workshops, courses, educational displays, art exhibitions, book rooms, open-air theatrical and musical performances, and other entertainment. (Full article...)
Saxifragales (colloquial/plural: the saxifrages) is an order of angiosperms, or flowering plants, containing 15 botanical families and around 100 genera, with nearly 2,500 species. Of the 15 families, many are small, with eight of them being monotypic (having only a single genus). The largest family is the Crassulaceae (stonecrops), a diverse group of mostly succulent plants, with about 35 genera. Saxifragales are found worldwide, primarily in temperate to subtropical zones, rarely being encountered growing wild in the tropics; however, many species are now cultivated throughout the world as knowledge of plant husbandry has improved. They can be found in a wide variety of environments, from deserts to fully aquatichabitats, with species adapted to alpine, forested or fully-aquatic habitats. Many are epiphytic or lithophytic, growing on exposed cliff faces, on trees or on rocks, and not requiring a highly organic or nutrient-dense substrate to thrive.
Globally, the saxifrages have a wide variety of uses by humans, ranging from textiles and timber to foodstuffs. Several families—such as the aforementioned Crassulaceae—and genera are of significant commercial importance in some countries and economies, being cultivated on a large scale for sale as ornamental plants. Apart from ornamentals, another highly-prized group are the Grossulariaceae (currants and gooseberries), particularly blackcurrants, redcurrants and white currants. (Full article...)
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Dracophyllum arboreum, commonly known as Chatham Island grass tree and tarahinau (Moriori), is a species of tree in the heath family Ericaceae. Endemic to the Chatham Islands of New Zealand, it reaches a height of 18 m (60 ft) and has leaves that differ between the juvenile and adult forms.
D. arboreum has wide light green leaves in its juvenile form, which become thin needles as it gains maturity. Flowering occurs from November through to February, yielding small white flowers which later become tiny brown fruit. It inhabits many different types of vegetation communities from near sea level to 270 m (886 ft), including swamps, cliffs, bogs, and shrublands. It has a range restricted to three Islands some 800 km (497 mi) east of New Zealand: the Chatham, Pitt, and Rangatira Islands. (Full article...)
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Hypericum aegypticum is a species of flowering plant of the St. John's wort family (Hypericaceae) which is native to the Eastern Mediterranean. It was described by Carl Linnaeus in the second volume of his Species Plantarum in 1753, who named it after Egypt despite it not being distributed there. The plant is commonly known as shrubby St. John's wort or Egyptian St. John's wort in English. Like other members of section Adenotrias, it is found among limestone rocks in coastal areas. While it has been evaluated as threatened on the island of Malta, the species has no legal protections.
The species is a shrub or shrublet that grows up to 2 meters (6.5 feet) tall with many branches, each having a single small flower with five yellow petals and many stamens. Its leaves lack hairs, and have densely patterned glands and large primary veins. The species is notable for its heterostyly, a trait which within the Hypericum genus is unique to section Adenotrias, and exhibits one of two heterostylous flower types called "pins" and "thrums". It has three subspecies, which vary in their distribution and phytochemical makeup. (Full article...)
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Buxbaumia viridis
Buxbaumia (bug moss, bug-on-a-stick, humpbacked elves, or elf-cap moss) is a genus of twelve species of moss (Bryophyta). It was first named in 1742 by Albrecht von Haller and later brought into modern botanical nomenclature in 1801 by Johann Hedwig to commemorate Johann Christian Buxbaum, a German physician and botanist who discovered the moss in 1712 at the mouth of the Volga River. The moss is microscopic for most of its existence, and plants are noticeable only after they begin to produce their reproductive structures. The asymmetrical spore capsule has a distinctive shape and structure, some features of which appear to be transitional from those in primitive mosses to most modern mosses. (Full article...)
... that while most lichens that grow on plants live on the surface, the sole species in Amazonotrema grows partially among the cells of the tree bark on which it lives?
Image 4A nineteenth-century illustration showing the morphology of the roots, stems, leaves and flowers of the rice plant Oryza sativa (from Botany)
Image 5This is an electron micrograph of the epidermal cells of a Brassica chinensis leaf. The stomates are also visible. (from Plant cell)
Image 6The 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 7Leaf lamina. The megaphyllous leaf architecture arose multiple times in different plant lineages (from Evolutionary history of plants)
Image 9The 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 10A 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 12The 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 13Thale cress, Arabidopsis thaliana, the first plant to have its genome sequenced, remains the most important model organism. (from Botany)
Image 18Structure 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 19Structure of a plant cell (from Plant cell)
Image 20Five of the key areas of study within plant physiology (from Botany)
Image 231 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 25The Linnaean Garden of Linnaeus' residence in Uppsala, Sweden, was planted according to his Systema sexuale. (from Botany)
Image 26Paper chromatography of some spinach leaf extract shows the various pigments present in their chloroplasts: yellowish xanthophylls, greenish chlorophylls a and b. (from Botany)
Image 29The food we eat comes directly or indirectly from plants such as rice. (from Botany)
Image 30A botanist preparing a plant specimen for mounting in the herbarium (from Botany)
Image 31Echeveria glauca in a Connecticut greenhouse. Botany uses Latin names for identification; here, the specific name glauca means blue. (from Botany)
Image 32Transverse section of a fossil stem of the Devonian vascular plant Rhynia gwynne-vaughani (from Botany)
Image 33The branching pattern of megaphyll veins may indicate their origin as webbed, dichotomising branches. (from Evolutionary history of plants)
Image 34The 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 36A 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)