Banksia integrifolia, commonly known as the coast banksia, is a species of tree that grows along the east coast of Australia. One of the most widely distributed Banksia species, it occurs between Victoria and Central Queensland in a broad range of habitats, from coastal dunes to mountains. It is highly variable in form, but is most often encountered as a tree up to 25 metres (82 ft) in height. Its leaves have dark green upper surfaces and white undersides, a contrast that can be striking on windy days.
Inflorescence with unopened buds (left), opened flowers (right)
Banksia marginata, commonly known as the silver banksia, is a species of tree or woody shrub in the plant genusBanksia found throughout much of southeastern Australia. It ranges from the Eyre Peninsula in South Australia to north of Armidale, New South Wales, and across Tasmania and the islands of Bass Strait. It grows in various habitats, including Eucalyptus forest, scrub, heathland and moorland. Banksia marginata varies widely in habit, ranging from a 20-centimetre (7.9 in) shrub to a 12-metre (40 ft) tree. The narrow leaves are linear and the yellow inflorescences (flower spikes) occur from late summer to early winter. The flower spikes fade to brown and then grey and develop woody follicles bearing the winged seeds. Originally described by Antonio José Cavanilles in 1800, further collections of B. marginata were designated as several separate species by Robert Brown in 1810. However, all were reclassified as a single species by George Bentham in 1870. No distinct subspecies have been recognised by Banksia expert Alex George, who nonetheless concedes that further work is needed.
Many species of bird, in particular honeyeaters, forage at the flower spikes, as do native and European honeybees. The response to bushfire varies. Some populations are serotinous: they are killed by fire and regenerate from large stores of seed which have been held in cones in the plant canopy and are released after a fire. Others regenerate from underground lignotubers or suckers from lateral roots. Although it has been used for timber, Banksia marginata is most commonly seen as a garden plant, with dwarf forms being commercially propagated and sold. (Full article...)
Image 3
Banksia dentata, commonly known as the tropical banksia, is a species of tree in the genusBanksia. It occurs across northern Australia, southern New Guinea and the Aru Islands. Growing as a gnarled tree to 7 m (23 ft) high, it has large green leaves up to 22 cm (8.7 in) long with dentate (toothed) margins. The cylindrical yellow inflorescences (flower spikes), up to 13 cm (5.1 in) high, appear over the cooler months, attracting various species of honeyeaters, sunbirds, the sugar glider and a variety of insects. Flowers fall off the ageing spikes, which swell and develop follicles containing up to two viable seeds each.
Banksia dentata is one of four Banksia species collected by Sir Joseph Banks in 1770, and one of the four species published in 1782 as part of Carolus Linnaeus the Younger's original description of Banksia. Within the genus, it is classified in the seriesSalicinae, a group of species from Australia's eastern states. Genetic studies show it is a basal member (early offshoot) within the group. Banksia dentata is found in tropical grassland known as savanna, associated with Pandanus and Melaleuca. It regenerates from bushfire by regrowing from its woody base, known as a lignotuber. (Full article...)
Image 4
The title page of the 1877 edition of Fertilisation of Orchids
Fertilisation of Orchids is a book by English naturalist Charles Darwin published on 15 May 1862 under the full explanatory title On the Various Contrivances by Which British and Foreign Orchids Are Fertilised by Insects, and On the Good Effects of Intercrossing. Darwin's previous book, On the Origin of Species, had briefly mentioned evolutionary interactions between insects and the plants they fertilised, and this new idea was explored in detail. Field studies and practical scientific investigations that were initially a recreation for Darwin—a relief from the drudgery of writing—developed into enjoyable and challenging experiments. Aided in his work by his family, friends, and a wide circle of correspondents across Britain and worldwide, Darwin tapped into the contemporary vogue for growing exotic orchids.
The book was his first detailed demonstration of the power of natural selection, and explained how complex ecological relationships resulted in the coevolution of orchids and insects. The view has been expressed that the book led directly or indirectly to all modern work on coevolution and the evolution of extreme specialisation. It influenced botanists, and revived interest in the neglected idea that insects played a part in pollinating flowers. It opened up the new study areas of pollination research and reproductive ecology, directly related to Darwin's ideas on evolution, and supported his view that natural selection led to a variety of forms through the important benefits achieved by cross-fertilisation. Although the general public showed less interest and sales of the book were low, it established Darwin as a leading botanist. Orchids was the first in a series of books on his innovative investigations into plants. (Full article...)
Banksia sphaerocarpa, commonly known as the fox banksia or round-fruit banksia, is a species of shrub or tree in the plant genus Banksia (family Proteaceae). It is generally encountered as a 1–2 m (3.3–6.6 ft) high shrub, and is usually smaller in the north of its range. This species has narrow green leaves, and brownish, orange or yellow round flower spikes which may be seen from January to July. It is widely distributed across the southwest of Western Australia, growing exclusively in sandy soils. It is usually the dominant plant in scrubland or low woodland. It is pollinated by, and is a food source for, birds, mammals, and insects.
First described in 1810 by botanist Robert Brown, B. sphaerocarpa has a complicated taxonomic history, and several taxa once classified as part of a broadly defined B. sphaerocarpa have since been named as species in their own right. At present, most authorities recognise five varieties; the largest variety, B. sphaerocarpa var. dolichostyla (ironcap banksia), is sometimes given species rank as B. dolichostyla. B. sphaerocarpa is classified as Not Threatened under the Wildlife Conservation Act of Western Australia, although two varieties have been placed on the Declared Rare and Priority Flora List—var. latifolia has been designated a Priority Two – Poorly Known taxon, and var. dolichostyla falls under Declared Rare Flora. None of the varieties are commonly seen in cultivation. (Full article...)
Banksia brownii, commonly known as feather-leaved banksia or Brown's banksia, is a species of shrub that grows in southwestWestern Australia. A plant with fine feathery leaves and large red-brown flower spikes, it usually grows as an upright bush around two metres (7 ft) high, but can also occur as a small tree or a low spreading shrub. First collected in 1829 and published the following year, it is placed in Banksiasubgenus Banksia, section Oncostylis, series Spicigerae. There are two genetically distinct forms.
Banksia brownii occurs naturally only in two population clusters between Albany and the Stirling Range in southwest Western Australia. In the Stirling Range it occurs among heath on rocky mountain slopes; further south it occurs among jarrahwoodland in shallow nutrient-poor sand. It has been evaluated as critically endangered by the International Union for Conservation of Nature (IUCN); all major populations care threatened by Phytophthora cinnamomi dieback, a disease to which the species is highly susceptible. Other threats include loss of habitat, commercial exploitation and changes to the fire regime. Highly valued by Australia's horticultural and cut flower industries, B. brownii is widely cultivated in areas not exposed to dieback. It prefers a sheltered position in soil with good drainage, and must be provided with some moisture over summer. (Full article...)
Image 7
A tulip, known as "the Viceroy" (viseroij), displayed in the 1637 Dutch catalogue Verzameling van een Meenigte Tulipaanen. Its bulb was offered for sale for between 3,000 and 4,200 guilders (florins) depending on weight (gewooge). A skilled craftsworker at the time earned about 300 guilders a year.
Tulip mania (Dutch: tulpenmanie) was a period during the Dutch Golden Age when contract prices for some bulbs of the recently introduced and fashionable tulip reached extraordinarily high levels. The major acceleration started in 1634 and then dramatically collapsed in February 1637. It is generally considered to have been the first recorded speculative bubble or asset bubble in history. In many ways, the tulip mania was more of a then-unknown socio-economic phenomenon than a significant economic crisis. It had no critical influence on the prosperity of the Dutch Republic, which was one of the world's leading economic and financial powers in the 17th century, with the highest per capita income in the world from about 1600 to about 1720. The term "tulip mania" is now often used metaphorically to refer to any large economic bubble when asset prices deviate from intrinsic values.
Forward markets appeared in the Dutch Republic during the 17th century. Among the most notable centred on the tulip market, at the height of tulip mania. At the peak of tulip mania, in February 1637, some single tulip bulbs sold for more than 10 times the annual income of a skilled artisan. Research is difficult because of the limited economic data from the 1630s, much of which come from biased and speculative sources. Some modern economists have proposed rational explanations, rather than a speculative mania, for the rise and fall in prices. For example, other flowers, such as the hyacinth, also had high initial prices at the time of their introduction, which then fell as the plants were propagated. The high asset prices may also have been driven by expectations of a parliamentary decree that contracts could be voided for a small cost, thus lowering the risk to buyers. (Full article...)
The fruits are small, round, and yellow, and can ripen and turn red at any time of year, peaking in spring and summer. Like all figs, the fruit is in the form of a syconium, an inverted inflorescence with the flowers lining an internal cavity. F. rubiginosa is exclusively pollinated by the fig wasp species Pleistodontes imperialis, which may comprise four cryptospecies. The syconia are also home to another fourteen species of wasp, some of which induce galls while others parasitise the pollinator wasps and at least two species of nematode. Many species of bird, including pigeons, parrots, and various passerines, eat the fruit. Ranging along the Australian east coast from Queensland to Bega in southern New South Wales (including the Port Jackson area, leading to its alternative name), F. rubiginosa grows in rainforest margins and rocky outcrops. It is used as a shade tree in parks and public spaces, and when potted is well-suited for use as an indoor plant or in bonsai. (Full article...)
Pinguicula moranensis/pɪŋˈɡwɪkjʊləˌmɒrəˈnɛnsɪs/ is a perennial rosette-forming insectivorousherb native to Mexico and Guatemala. A species of butterwort, it forms summer rosettes of flat, succulent leaves up to 10 centimeters (4 in) long, which are covered in mucilaginous (sticky) glands that attract, trap, and digest arthropod prey. Nutrients derived from the prey are used to supplement the nutrient-poor substrate that the plant grows in. In the winter the plant forms a non-carnivorous rosette of small, fleshy leaves that conserves energy while food and moisture supplies are low. Single pink, purple, or violet flowers appear twice a year on upright stalks up to 25 centimeters long.
The species was first collected by Humboldt and Bonpland on the outskirts of Mina de Morán in the Sierra de Pachuca of the modern-day Mexican state of Hidalgo on their Latin American expedition of 1799–1804. Based on these collections, Carl Sigismund Kunth described this species in Nova Genera et Species Plantarum in 1817. The extremely variable species has been redefined at least twice since, while several new species have been segregated from it based on various geographical or morphological distinctions, although the legitimacy of some of these is still debated. P. moranensis remains the most common and most widely distributed member of the Section Orcheosanthus. It has long been cultivated for its carnivorous nature and attractive flowers, and is one of the most common butterworts in cultivation. (Full article...)
Banksia spinulosa, the hairpin banksia, is a species of woody shrub, of the genus Banksia in the family Proteaceae, native to eastern Australia. Widely distributed, it is found as an understorey plant in open dry forest or heathland from Victoria to northern Queensland, generally on sandstone though sometimes also clay soils. It generally grows as a small shrub to 2 metres (7 ft) in height, though can be a straggly tree to 6 metres (20 ft). It has long narrow leaves with inflorescences which can vary considerably in coloration; while the spikes are gold or less commonly yellowish, the emergent styles may be a wide range of colours – from black, purple, red, orange or yellow.
Banksia spinulosa was named by James Edward Smith in England in 1793, after being collected by John White, most likely in 1792. He gave it the common name prickly-leaved banksia, though this has fallen out of use. With four currently recognised varieties, the species has had a complicated taxonomic history, with two varieties initially described as separate species in the early 19th century. A fourth, from the New England region, has only recently been described. However, there has been disagreement whether one, var. cunninghamii, is distinct enough to once again have specific status. The pre-eminent authority on Banksia, Alex George, concedes there is still more work to be done on the Banksia spinulosa complex. (Full article...)
Image 12
Banksia caleyi, commonly known as Caley's banksia or red lantern banksia, is a species of woody shrub of the family Proteaceae native to Western Australia. It generally grows as a dense shrub up to 2 m (7 ft) tall, has serrated leaves and red, pendent (hanging) inflorescences which are generally hidden in the foliage. First described by Scottish naturalist Robert Brown in 1830, Banksia caleyi was named in honour of the English botanist George Caley. No subspecies are recognised. It is one of three or four related species with hanging inflorescences, which is an unusual feature within the genus.
Johann George Adam Forster, also known as Georg Forster (German pronunciation: [ˈɡeːɔʁk ˈfɔʁstɐ], 27 November 1754 – 10 January 1794), was a German 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...)
Image 14
Second-year plant starting to flower, with a dead stem of the previous year, behind left
Verbascum thapsus, the great mullein, greater mullein or common mullein is a species of mullein native to Europe, northern Africa, and Asia, and introduced in the Americas and Australia.
It is a hairy biennial plant that can grow to 2 m tall or more. Its small, yellow flowers are densely grouped on a tall stem, which grows from a large rosette of leaves. It grows in a wide variety of habitats, but prefers well-lit, disturbed soils, where it can appear soon after the ground receives light, from long-lived seeds that persist in the soil seed bank. It is a common weedy plant that spreads by prolifically producing seeds, and has become invasive in temperate world regions. It is a minor problem for most agricultural crops, since it is not a competitive species, being intolerant of shade from other plants and unable to survive tilling. It also hosts many insects, some of which can be harmful to other plants. Although individuals are easy to remove by hand, populations are difficult to eliminate permanently. (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...)
Chamaenerion is a genus of flowering plants in the familyOnagraceae (the evening primrose or willowherb family). It has sometimes been included in the genus Epilobium. Members of the genus may be called willowherbs (along with Epilobium), or fireweeds, based on a common name used for C. angustifolium. They are upright herbaceousperennials, growing from a woody base or from rhizomes, with racemes of usually purple to pink flowers. All species are found in the northern hemisphere. Most occur in moist habitats; C. angustifolium is the exception, favouring disturbed ground. (Full article...)
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...)
Image 3
The diversity of leaves
A leaf is a principal appendage of the stem of a vascular plant, usually borne laterally aboveground 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 photosynthetic tissue 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. 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 that 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 includes 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...)
Mendel worked with seven characteristics of pea plants: plant height, pod shape and color, seed shape and color, and flower position and color. Taking seed color as an example, Mendel showed that when a true-breeding yellow pea and a true-breeding green pea were cross-bred their offspring always produced yellow seeds. However, in the next generation, the green peas reappeared at a ratio of 1 green to 3 yellow. To explain this phenomenon, Mendel coined the terms "recessive" and "dominant" in reference to certain traits. In the preceding example, the green trait, which seems to have vanished in the first filial generation, is recessive and the yellow is dominant. He published his work in 1866, demonstrating the actions of invisible "factors"—now called genes—in predictably determining the traits of an organism. (Full article...)
Ethnobotany is the study of a region's plants and their practical uses through the traditional knowledge of a local culture and people. An ethnobotanist thus strives to document the local customs involving the practical uses of local flora for many aspects of life, such as plants as medicines, foods, intoxicants and clothing. Richard Evans Schultes, often referred to as the "father of ethnobotany", explained the discipline in this way:
Ethnobotany simply means ... investigating plants used by societies in various parts of the world.
Since the time of Schultes, the field of ethnobotany has grown from simply acquiring ethnobotanical knowledge to that of applying it to a modern society, primarily in the form of pharmaceuticals. Intellectual property rights and benefit-sharing arrangements are important issues in ethnobotany. (Full article...)
Along with the Asteraceae, they are one of the two largest families of flowering plants. The Orchidaceae have about 28,000 currently accepted species, distributed in about 763 genera. The determination of which family is larger is still under debate, because verified data on the members of such enormous families are continually in flux. Regardless, the number of orchid species is nearly equal to the number of bony fishes, more than twice the number of bird species, and about four times the number of mammal species. (Full article...)
The arrival of humans around 50,000 years ago and the settlement by Europeans from 1788, has had a significant impact on the flora. The use of fire-stick farming by Aboriginal people led to significant changes in the distribution of plant species over time, and the large-scale modification or destruction of vegetation for agriculture and urban development since 1788 has altered the composition of most terrestrial ecosystems, leading to the extinction of 61 plant species by 2006, and endangering over 1000 more. (Full article...)
Image 9
Botanical nomenclature is the formal, scientific naming of plants. It is related to, but distinct from taxonomy. Plant taxonomy is concerned with grouping and classifying plants; botanical nomenclature then provides names for the results of this process. The starting point for modern botanical nomenclature is Linnaeus' Species Plantarum of 1753. Botanical nomenclature is governed by the International Code of Nomenclature for algae, fungi, and plants (ICN), which replaces the International Code of Botanical Nomenclature (ICBN). Fossil plants are also covered by the code of nomenclature.
Agroforestry is a land use management system in which trees or shrubs are grown around or among crops or pastureland. Trees produce a wide range of useful and marketable products from fruits/nuts, medicines, wood products, etc. This intentional combination of agriculture and forestry has multiple benefits, such as greatly enhanced yields from staple food crops, enhanced farmer livelihoods from income generation, increased biodiversity, improved soil structure and health, reduced erosion, and carbon sequestration. Agroforestry practices are highly beneficial in the tropics, especially in subsistence smallholdings in sub-Saharan Africa and have been found to be beneficial in Europe and the United States.
Agroforestry shares principles with intercropping but can also involve much more complex multi-strata agroforests containing hundreds of species. Agroforestry can also utilise nitrogen-fixing plants such as legumes to restore soil nitrogen fertility. The nitrogen-fixing plants can be planted either sequentially or simultaneously. (Full article...)
Opuntia, commonly called prickly pear or pear cactus, is a genus of flowering plants in the cactusfamily Cactaceae. Prickly pears are also known as tuna (fruit), sabra, nopal (paddle, plural nopales) from the Nahuatl word nōpalli for the pads, or nostle, from the Nahuatl word nōchtli for the fruit; or 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 Indian fig opuntia (O. ficus-indica). (Full article...)
Image 12
Only a few of the many varieties of potato are commercially grown; others are heirlooms.
An heirloom plant, heirloom variety, heritage fruit (Australia and New Zealand), or heirloom vegetable (especially in Ireland and the UK) is an old cultivar of a plant used for food that is grown and maintained by gardeners and farmers, particularly in isolated or ethnic minority communities of the Western world. These were commonly grown during earlier periods in human history, but are not used in modern large-scale agriculture.
In some parts of the world, it is illegal to sell seeds of cultivars that are not listed as approved for sale. The Henry Doubleday Research Association, now known as Garden Organic, responded to this legislation by setting up the Heritage Seed Library to preserve seeds of as many of the older cultivars as possible. However, seed banks alone have not been able to provide sufficient insurance against catastrophic loss. In some jurisdictions, like Colombia, laws have been proposed that would make seed saving itself illegal. (Full article...)
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...)
When an insect or spider crawling along the leaves contacts a hair, the trap prepares to close, snapping shut only if another contact occurs within approximately twenty seconds of the first strike. Triggers may occur with a tenth of a second of contact. The requirement of redundant triggering in this mechanism serves as a safeguard against wasting energy by trapping objects with no nutritional value, and the plant will only begin digestion after five more stimuli to ensure it has caught a live bug worthy of consumption. (Full article...)
Image 15
Structure of the photosynthetic reaction centre from Rhodopseudomonas viridis (PDB: 1PRC). Middle transmembrane section is the two subunits in this family; green blocks represent chlorophyll. Top section is the 4-heme (red) cytochrome c subunit (infobox below). The bottom section along with its connected TM helices is the H subunit.
Plants, algae, and cyanobacteria have one type of PRC for each of its two photosystems. Non-oxygenic bacteria, on the other hand, have an RC resembling either the Photosystem I centre (Type I) or the Photosystem II centre (Type II). In either case, PRCs have two related proteins (L/M; D1/D2; PsaA/PsaB) making up a quasi-symmetrical 5-helical core complex with pockets for pigment binding. The two types are structurally related and share a common ancestor. Each type have different pockets for ligands to accommodate their specific reactions: while Type I RCs use iron sulfur clusters to accept electrons, Type II RCs use quinones. The centre units of Type I RCs also have six extra transmembrane helices for gathering energy. (Full article...)
Samanea saman, also known as the rain tree or Albizia saman, is a species of flowering tree in the pea family, Fabaceae, that is native to Central and South America. It is a wide-canopied tree with a large umbrella-shaped crown, and usually reaches a height of 15–25 m (49–82 ft) with a diameter of 30 m (98 ft). The tree has pinkish flowers with white and red stamens, set on heads with around 12–25 flowers per head. These heads may number in the thousands, covering the whole tree.
These are good articles, which meet a core set of high editorial standards..
Image 1
Piper cubeba, cubeb or tailed pepper is a plant in genusPiper, cultivated for its fruit and essential oil. It is mostly grown in Java and Sumatra, hence sometimes called Java pepper. The fruits are gathered before they are ripe, and carefully dried. Commercial cubeb consists of the dried berries, similar in appearance to black pepper, but with stalks attached – the "tails" in "tailed pepper". The dried pericarp is wrinkled, and its color ranges from grayish brown to black. The seed is hard, white and oily. The odor of cubeb is described as agreeable and aromatic and the taste as pungent, acrid, slightly bitter and persistent. It has been described as tasting like allspice, or like a cross between allspice and black pepper.
Cubeb came to Europe via India through the trade with the Arabs. The name cubeb comes from Arabickabāba (كبابة) by way of Old Frenchquibibes. Cubeb is mentioned in alchemical writings by its Arabic name. In his Theatrum Botanicum, John Parkinson tells that the king of Portugal (Possibly either Philip IV of Spain or John IV of Portugal, as that year was marked by the start of the Portuguese Restoration War) prohibited the sale of cubeb to promote black pepper (Piper nigrum) around 1640. It experienced a brief resurgence in 19th-century Europe for medicinal uses, but has practically vanished from the European market since. It continues to be used as a flavoring agent for gins and cigarettes in the West, and as a seasoning for food in Indonesia. (Full article...)
It is endemic to the San Francisco Bay Area of California, United States, and occurs only at altitudes less than 620 metres (2,034 ft). P. bellidiflora is found chiefly on rocky, grassy areas. The conservation status of this species was, as of 1999, characterized by a declining population, with a severely diminished and fragmented range. The specific bellidiflora refers to the similarity of the flowers with those of common daisies (Bellis). (Full article...)
Image 4
The frontispiece to an illustrated 1644 edition, Amsterdam
Historia Plantarum was written some time between c. 350 BC and c. 287 BC in ten volumes, of which nine survive. In the book, Theophrastus described plants by their uses, and attempted a biological classification based on how plants reproduced, a first in the history of botany. He continually revised the manuscript, and it remained in an unfinished state on his death. The condensed style of the text, with its many lists of examples, indicate that Theophrastus used the manuscript as the working notes for lectures to his students, rather than intending it to be read as a book. (Full article...)
Image 5
Osteospermum 'Pink Whirls' A cultivar selected for its intriguing and colourful flowers
A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture, or carefully controlled seed production. Most cultivars arise from purposeful 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...)
Image 6
Betula pendula, commonly known as silver birch, warty birch, European white birch, or East Asian white birch, is a species of tree in the familyBetulaceae, native to Europe and parts of Asia, though in southern Europe, it is only found at higher altitudes. Its range extends into Siberia, China, and southwest Asia in the mountains of northern Turkey, the Caucasus, and northern Iran. It has been introduced into North America, where it is known as the European white birch or weeping birch and is considered invasive in some states in the United States and parts of Canada. The tree can also be found in more temperate regions of Australia.
The silver birch is a medium-sized deciduous tree that owes its common name to the white peeling bark on the trunk. The twigs are slender and often pendulous and the leaves are roughly triangular with doubly serrate margins and turn yellow and brown in autumn before they fall. The flowers are catkins and the light, winged seeds get widely scattered by the wind. The silver birch is a hardy tree, a pioneer species, and one of the first trees to appear on bare or fire-swept land. Many species of birds and animals are found in birch woodland, the tree supports a wide range of insects and the light shade it casts allows shrubby and other plants to grow beneath its canopy. It is planted decoratively in parks and gardens and is used for forest products such as joinery timber, firewood, tanning, racecourse jumps, and brooms. Various parts of the tree are used in traditional medicine and the bark contains triterpenes, which have been shown to have medicinal properties. (Full article...)
Image 7
Ornithogalum umbellatum, the garden star-of-Bethlehem, grass lily, nap-at-noon, or eleven-o'clock lady, a species of the genus Ornithogalum, is a perennialbulbousflowering plant in the asparagus family (Asparagaceae). O. umbellatum is a relatively short plant, occurring in tufts of basal linear leaves, producing conspicuous white flowers, in a stellate pattern, in mid to late spring. The flowers open late in the day (hence some of its common names), but when closed have a green stripe on the outside. It is native throughout most of southern and central Europe, and north-western Africa. O. umbellatum is often grown as a garden ornamental, but in North America and other areas it has escaped cultivation and can be found in many areas, where it may become an invasive noxious weed. Parts of the plant are considered poisonous, but are used in some regional cuisines. Essences are also sold as patent remedies. O. umbellatum has been depicted in art by artists such as Leonardo da Vinci, and folklore has suggested it originally grew from fragments of the star of Bethlehem, hence its horticultural name. (Full article...)
Image 8
Veronica jovellanoides, commonly known as Riverhead speedwell, is a threatened flowering plant in the family Plantaginaceae. Endemic to New Zealand, only three plants are known in the wild. All are found within the Ernest Morgan Reserve, a 20ha forest northwest of Auckland. Its discovery is accredited to a retired plant nursery owner, Geoff Davidson, who organised the land's protection a few decades prior, and found it by chance on a walk in November 2007.
V. jovellanoides has a prostrate growth habit, forming large 2 to 3 m (6.6 to 9.8 ft) mats on the ground, and long stems with small, spatula-shaped leaves. Flowering begins in spring (September to November in New Zealand), producing small four-petalled white flowers which have a purple ring around their throats; the inner and centre-most section of the flower. Once pollinated, these become small brown seeds which are dispersed by the wind. (Full article...)
Image 9
Ripe honeynut squash
Honeynut squash is an interspecific hybridwinter squash cultivar bred from butternut and buttercup squash. It has dark tan to orange skin with orange fleshy pulp. When ripe, it turns from green to a deep orange and becomes sweeter and richer. Honeynut squash has a similar shape and flavor to butternut squash but averages about half the size and is sweeter. It has two to three times more beta-carotene than butternut squash. Honeynut squash can be roasted, sautéed, puréed, added to soups, stews, and braises, and has enough sugar content for desserts.
Symphyotrichum novae-angliae (formerly Aster novae-angliae) is a species of flowering plant in the aster family (Asteraceae) native to central and eastern North America. Commonly known as New England aster, hairy Michaelmas-daisy, or Michaelmas daisy, it is a perennial, herbaceous plant usually between 30 and 120 centimeters (1 and 4 feet) tall and 60 to 90 cm (2 to 3 ft) wide.
The usually deep purple flowers have up to 100 ray florets which are rarely pink or white. These surround the flower centers which are composed of just as many tiny yellow disk florets. The plant grows naturally in clumps, with several erect stems emerging from a single point. The stems are stout, hairy, and mostly unbranched. The untoothed, lance-shaped leaves clasp the stem with earlobe-like appendages, and the lower stem leaves often wither by the time of flowering. (Full article...)
Erythranthe, the monkey-flowers and musk-flowers, is a diverse plantgenus with more than 120 members (as of 2022) in the familyPhrymaceae. Erythranthe was originally described as a separate genus, then generally regarded as a section within the genus Mimulus, and recently returned to generic rank. Mimulus sect. Diplacus was segregated from Mimulus as a separate genus at the same time. Mimulus remains as a small genus of eastern North America and the Southern Hemisphere. Molecular data show Erythranthe and Diplacus to be distinct evolutionary lines that are distinct from Mimulus as strictly defined, although this nomenclature is controversial.
Member species are usually annuals or herbaceousperennials. Flowers are red, pink, or yellow, often in various combinations. A large number of the Erythranthe species grow in moist to wet soils with some growing even in shallow water. They are not very drought resistant, but many of the species now classified as Diplacus are. Species are found at elevations from oceanside to high mountains as well as a wide variety of climates, though most prefer wet areas such as riverbanks. (Full article...)
Image 12
Various Cactaceae from Brockhaus' Konversations-Lexikon v. 2 1892
A cactus (pl. cacti, cactuses, or less commonly, cactus) is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word cactus derives, through Latin, from the Ancient Greek word κάκτος (káktos), a name originally used by Theophrastus for a spiny plant whose identity is now not certain. Cacti occur in a wide range of shapes and sizes. Although some species live in quite humid environments, most cacti live in habitats subject to at least some drought. Many live in extremely dry environments, even being found in the Atacama Desert, one of the driest places on Earth. Because of this, cacti show many adaptations to conserve water. For example, almost all cacti are succulents, meaning they have thickened, fleshy parts adapted to store water. Unlike many other succulents, the stem is the only part of most cacti where this vital process takes place. Most species of cacti have lost true leaves, retaining only spines, which are highly modified leaves. As well as defending against herbivores, spines help prevent water loss by reducing air flow close to the cactus and providing some shade. In the absence of true leaves, cacti's enlarged stems carry out photosynthesis. Cacti are native to the Americas, ranging from Patagonia in the south to parts of western Canada in the north—except for Rhipsalis baccifera, which also grows in Africa and Sri Lanka.
Cactus spines are produced from specialized structures called areoles, a kind of highly reduced branch. Areoles are an identifying feature of cacti. As well as spines, areoles give rise to flowers, which are usually tubular and multipetaled. Many cacti have short growing seasons and long dormancies and are able to react quickly to any rainfall, helped by an extensive but relatively shallow root system that quickly absorbs any water reaching the ground surface. Cactus stems are often ribbed or fluted, which allows them to expand and contract easily for quick water absorption after rain, followed by retention over long drought periods. Like other succulent plants, most cacti employ a special mechanism called "crassulacean acid metabolism" (CAM) as part of photosynthesis. Transpiration, during which carbon dioxide enters the plant and water escapes, does not take place during the day at the same time as photosynthesis, but instead occurs at night. The plant stores the carbon dioxide it takes in as malic acid, retaining it until daylight returns, and only then using it in photosynthesis. Because transpiration takes place during the cooler, more humid night hours, water loss is significantly reduced. (Full article...)
Image 13
Commelina communis flowers
Commelina communis, commonly known as the Asiatic dayflower, is an herbaceousannual plant in the dayflower family. It gets its name because the blooms last for only one day. It is native throughout much of East Asia and northern parts of Southeast Asia. In China, the plant is known as yazhicao (simplified Chinese: 鸭跖草; traditional Chinese: 鴨跖草; pinyin: yāzhīcǎo), roughly translating to "duckfoot herb", while in Japan it is known as tsuyukusa (露草, tsuyukusa), meaning "dew herb". It has also been introduced to parts of central and southeastern Europe and much of eastern North America, where it has spread to become a noxious weed. It is common in disturbed sites and in moist soil. The flowers emerge from summer through fall and are distinctive with two relatively large blue petals and one very small white petal.
The Asiatic dayflower plant serves as the type species for its large genus. Linnaeus picked the name Commelina in honour of the two Dutch botanists of the Commelijn family, using the two large showy petals of Commelina communis to symbolise them. Linnaeus described the species in the first edition of his landmark work, Species Plantarum, in 1753. Long before the plant was studied in Europe, however, it had been used for generations in traditional Chinese medicine. The flowers have also been used in Japan to produce a dye and a pigment that was used in many world-renowned Ukiyo-ewoodcuts from the 18th and early 19th centuries. In the modern era the plant has found limited use as a model organism in the field of plant physiology due to its complex pigment chemistry and the ease of viewing its stomata. (Full article...)
Image 14
A portrait of Christian Ramsay, beside a watercolour of a flower and a bird.
A. brownii was first discovered during the Tanager Expedition in 1923 by botanist Edward Leonard Caum. It differed from other Hawaiian species of Amaranthus with its spineless leaf axils, linear leaves, and indehiscent fruits. It was one of 26 vascular plants on Nihoa, 17 of which are indigenous, six alien, and three endemic only to Nihoa; these latter three included A. brownii, the Nihoa fan palm or loulu, and the Nihoa carnation. A. brownii was considered the rarest plant on Nihoa and was not directly observed on the island after 1983. Past expeditions collected plant samples and seeds, but no specimens managed to survive ex-situ conservation efforts outside of its native habitat. Consequently, there are no known plants or seeds from A. brownii in any botanical garden. (Full article...)
... that campaigning by climate activist Kimiko Hirata halted plans to build 17 new coal-fired power plants following the Fukushima nuclear disaster in Japan?
Image 2Structure of a plant cell (from Plant cell)
Image 3The food we eat comes directly or indirectly from plants such as rice. (from Botany)
Image 4The Linnaean Garden of Linnaeus' residence in Uppsala, Sweden, was planted according to his Systema sexuale. (from Botany)
Image 5The 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 14Structure 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 15A nineteenth-century illustration showing the morphology of the roots, stems, leaves and flowers of the rice plant Oryza sativa (from Botany)
Image 181 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 23A 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)
Image 24A 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 25The 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 27The 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 28Five of the key areas of study within plant physiology (from Botany)
Image 36The 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 40Echeveria glauca in a Connecticut greenhouse. Botany uses Latin names for identification; here, the specific name glauca means blue. (from Botany)