126-416: ~24, see text Macrotyloma is a genus of plants in the legume family which include several species of edible beans . Some species are also used as fodder for livestock. Species include: This Phaseoleae -related article is a stub . You can help Misplaced Pages by expanding it . Fabaceae The Fabaceae ( / f ə ˈ b eɪ s i . iː , - ˌ aɪ / ) or Leguminosae , commonly known as
252-429: A monophyletic taxonomic group but consist of a wide variety of plant species that have independently evolved a trunk and branches as a way to tower above other plants to compete for sunlight. The majority of tree species are angiosperms or hardwoods; of the rest, many are gymnosperms or softwoods. Trees tend to be long-lived, some reaching several thousand years old. Trees evolved around 370 million years ago, and it
378-409: A symbiotic relationship with Frankia species, a filamentous bacterium that can fix nitrogen from the air, converting it into ammonia . They have actinorhizal root nodules on their roots in which the bacteria live. This process enables the tree to live in low nitrogen habitats where they would otherwise be unable to thrive. The plant hormones called cytokinins initiate root nodule formation, in
504-405: A tree is a perennial plant with an elongated stem , or trunk , usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth , plants that are usable as lumber or plants above a specified height. In wider definitions, the taller palms , tree ferns , bananas , and bamboos are also trees. Trees are not
630-416: A classic example of parallel evolution . With an estimated 60,000-100,000 species, the number of trees worldwide might total twenty-five per cent of all living plant species. The greatest number of these grow in tropical regions; many of these areas have not yet been fully surveyed by botanists , making tree diversity and ranges poorly known. The majority of tree species are angiosperms or hardwoods. Of
756-503: A drier savanna climate and insufficient rainfall to support dense forests, the canopy is not closed, and plenty of sunshine reaches the ground which is covered with grass and scrub. Acacia and baobab are well adapted to living in such areas. The roots of a tree serve to anchor it to the ground and gather water and nutrients to transfer to all parts of the tree. They are also used for reproduction, defence, survival, energy storage and many other purposes. The radicle or embryonic root
882-418: A hundred litres are required to make one litre of birch syrup. Various parts of trees are used as spices. These include cinnamon , made from the bark of the cinnamon tree ( Cinnamomum zeylanicum ) and allspice , the dried small fruits of the pimento tree ( Pimenta dioica ). Nutmeg is a seed found in the fleshy fruit of the nutmeg tree ( Myristica fragrans ) and cloves are the unopened flower buds of
1008-509: A process closely related to mycorrhizal association. It has been demonstrated that some trees are interconnected through their root system, forming a colony. The interconnections are made by the inosculation process, a kind of natural grafting or welding of vegetal tissues. The tests to demonstrate this networking are performed by injecting chemicals, sometimes radioactive , into a tree, and then checking for its presence in neighbouring trees. The roots are, generally, an underground part of
1134-404: A process known as cladoptosis . The crown is the spreading top of a tree including the branches and leaves, while the uppermost layer in a forest, formed by the crowns of the trees, is known as the canopy . A sapling is a young tree. Many tall palms are herbaceous monocots, which do not undergo secondary growth and never produce wood. In many tall palms, the terminal bud on the main stem
1260-833: A rhizobia species may often infect more than one host species. This means that one plant species may be infected by more than one species of bacteria. For example, nodules in Acacia senegal can contain seven species of rhizobia belonging to three different genera. The most distinctive characteristics that allow rhizobia to be distinguished apart are the rapidity of their growth and the type of root nodule that they form with their host. Root nodules can be classified as being either indeterminate, cylindrical and often branched, and determinate, spherical with prominent lenticels. Indeterminate nodules are characteristic of legumes from temperate climates, while determinate nodules are commonly found in species from tropical or subtropical climates. Nodule formation
1386-422: A second spurt of growth, a Lammas growth may occur which is believed to be a strategy to compensate for loss of early foliage to insect predators. Primary growth is the elongation of the stems and roots. Secondary growth consists of a progressive thickening and strengthening of the tissues as the outer layer of the epidermis is converted into bark and the cambium layer creates new phloem and xylem cells. The bark
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#17328694135791512-665: A short hypanthium , usually cup-shaped. There are normally ten stamens and one elongated superior ovary , with a curved style . They are usually arranged in indeterminate inflorescences . Fabaceae are typically entomophilous plants (i.e. they are pollinated by insects ), and the flowers are usually showy to attract pollinators . In the Caesalpinioideae , the flowers are often zygomorphic , as in Cercis , or nearly symmetrical with five equal petals, as in Bauhinia . The upper petal
1638-489: A significant role in reducing erosion and moderating the climate . They remove carbon dioxide from the atmosphere and store large quantities of carbon in their tissues. Trees and forests provide a habitat for many species of animals and plants. Tropical rainforests are among the most biodiverse habitats in the world. Trees provide shade and shelter , timber for construction, fuel for cooking and heating, and fruit for food as well as having many other uses. In much of
1764-424: A similar growth form, by usually growing larger and having a single main stem; but there is no consistent distinction between a tree and a shrub, made more confusing by the fact that trees may be reduced in size under harsher environmental conditions such as on mountains and subarctic areas. The tree form has evolved separately in unrelated classes of plants in response to similar environmental challenges, making it
1890-467: A single tree species, which will not flourish in the absence of its mycorrhizal associate. Others are generalists and associate with many species. The tree acquires minerals such as phosphorus from the fungus, while the fungus obtains the carbohydrate products of photosynthesis from the tree. The hyphae of the fungus can link different trees and a network is formed, transferring nutrients and signals from one place to another. The fungus promotes growth of
2016-636: A slightly looser definition; while the Joshua tree , bamboos and palms do not have secondary growth and never produce true wood with growth rings, they may produce "pseudo-wood" by lignifying cells formed by primary growth. Tree species in the genus Dracaena , despite also being monocots, do have secondary growth caused by meristem in their trunk, but it is different from the thickening meristem found in dicotyledonous trees. Aside from structural definitions, trees are commonly defined by use; for instance, as those plants which yield lumber. The tree growth habit
2142-430: A staple, essential as a source of protein. Their ability to fix atmospheric nitrogen reduces fertilizer costs for farmers and gardeners who grow legumes, and means that legumes can be used in a crop rotation to replenish soil that has been depleted of nitrogen . Legume seeds and foliage have a comparatively higher protein content than non-legume materials, due to the additional nitrogen that legumes receive through
2268-484: A tree is any plant with the general form of an elongated stem, or trunk, which supports the photosynthetic leaves or branches at some distance above the ground. Trees are also typically defined by height, with smaller plants from 0.5 to 10 m (1.6 to 32.8 ft) being called shrubs , so the minimum height of a tree is only loosely defined. Large herbaceous plants such as papaya and bananas are trees in this broad sense. A commonly applied narrower definition
2394-436: A wide range of edible fruits are found in the tropics. Other commercially important fruit include dates, figs and olives. Palm oil is obtained from the fruits of the oil palm ( Elaeis guineensis ). The fruits of the cocoa tree ( Theobroma cacao ) are used to make cocoa and chocolate and the berries of coffee trees, Coffea arabica and Coffea canephora , are processed to extract the coffee beans. In many rural areas of
2520-416: A wide range of shapes and sizes, in response to environmental pressures including climate and predation. They can be broad or needle-like, simple or compound, lobed or entire, smooth or hairy, delicate or tough, deciduous or evergreen. The needles of coniferous trees are compact but are structurally similar to those of broad-leaved trees. They are adapted for life in environments where resources are low or water
2646-736: A wide variety of growth forms , including trees, shrubs, herbaceous plants, and even vines or lianas . The herbaceous plants can be annuals, biennials , or perennials, without basal or terminal leaf aggregations. Many Legumes have tendrils. They are upright plants, epiphytes , or vines. The latter support themselves by means of shoots that twist around a support or through cauline or foliar tendrils . Plants can be heliophytes , mesophytes , or xerophytes . The leaves are usually alternate and compound. Most often they are even- or odd- pinnately compound (e.g. Caragana and Robinia respectively), often trifoliate (e.g. Trifolium , Medicago ) and rarely palmately compound (e.g. Lupinus ), in
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#17328694135792772-508: A wide variety of taxa representing the main lineages in the Fabaceae have been found in the fossil record dating from the middle to the late Eocene , suggesting that the majority of the modern Fabaceae groups were already present and that a broad diversification occurred during this period. Therefore, the Fabaceae started their diversification approximately 60 million years ago and the most important clades separated 50 million years ago. The age of
2898-542: A widespread diverse group of which the only survivor is the maidenhair tree Ginkgo biloba . This is considered to be a living fossil because it is virtually unchanged from the fossilised specimens found in Triassic deposits. During the Mesozoic (245 to 66 million years ago) the conifers flourished and became adapted to live in all the major terrestrial habitats. Subsequently, the tree forms of flowering plants evolved during
3024-549: Is a flavouring obtained from distilling bark from the roots of the sassafras tree ( Sassafras albidum ). The leaves of trees are widely gathered as fodder for livestock and some can be eaten by humans but they tend to be high in tannins which makes them bitter. Leaves of the curry tree ( Murraya koenigii ) are eaten, those of kaffir lime ( Citrus × hystrix ) (in Thai food ) and Ailanthus (in Korean dishes such as bugak ) and those of
3150-512: Is a rudimentary stalk and neatly folded miniature leaves, ready to expand when the next growing season arrives. Buds also form in the axils of the leaves ready to produce new side shoots. A few trees, such as the eucalyptus , have "naked buds" with no protective scales and some conifers, such as the Lawson's cypress , have no buds but instead have little pockets of meristem concealed among the scale-like leaves. When growing conditions improve, such as
3276-416: Is a sudden movement of sap at the end of the winter as trees prepare to burst into growth. In North America, the sap of the sugar maple ( Acer saccharum ) is used in the production of maple syrup . About 90% of the sap is water, the remaining 10% being a mixture of various sugars and certain minerals. The sap is harvested by drilling holes in the trunks of the trees and collecting the liquid that flows out of
3402-545: Is also found in the southern hemisphere, as for example in the Eastern Australia temperate forest, characterised by Eucalyptus forest and open acacia woodland. In tropical regions with a monsoon or monsoon-like climate, where a drier part of the year alternates with a wet period as in the Amazon rainforest , different species of broad-leaved trees dominate the forest, some of them being deciduous. In tropical regions with
3528-528: Is an evolutionary adaptation found in different groups of plants: by growing taller, trees are able to compete better for sunlight. Trees tend to be tall and long-lived, some reaching several thousand years old. Several trees are among the oldest organisms now living. Trees have modified structures such as thicker stems composed of specialised cells that add structural strength and durability, allowing them to grow taller than many other plants and to spread out their foliage. They differ from shrubs , which have
3654-511: Is closely related to human evolution . The family Fabaceae includes a number of plants that are common in agriculture including Glycine max ( soybean ), Phaseolus (beans), Pisum sativum ( pea ), Cicer arietinum ( chickpeas ), Vicia faba ( broad bean ), Medicago sativa ( alfalfa ), Arachis hypogaea ( peanut ), Ceratonia siliqua (carob), Trigonella foenum-graecum ( fenugreek ), and Glycyrrhiza glabra ( liquorice ). A number of species are also weedy pests in different parts of
3780-515: Is common throughout the Fabaceae. It is found in the majority of its members that only form an association with rhizobia, which in turn form an exclusive symbiosis with the Fabaceae (with the exception of Parasponia , the only genus of the 18 Ulmaceae genera that is capable of forming nodules). Nodule formation is present in all the Fabaceae sub-families, although it is less common in the Caesalpinioideae. All types of nodule formation are present in
3906-418: Is continually replaced by a living layer of cells called the cork cambium or phellogen. The London plane ( Platanus × hispanica ) periodically sheds its bark in large flakes. Similarly, the bark of the silver birch ( Betula pendula ) peels off in strips. As the tree's girth expands, newer layers of bark are larger in circumference, and the older layers develop fissures in many species. In some trees such as
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4032-497: Is defined by isoxazolin-5-one derivatives. These compounds occur in particular together with 3-NPA and related derivatives at the same time in the same species, as found in Astragalus canadensis and Astragalus collinus . 3-NPA and isoxazlin-5-one derivatives also occur in many species of leaf beetles (see defense in insects ). Legumes are economically and culturally important plants due to their extraordinary diversity and abundance,
4158-499: Is developed by the Indian banyan . Many large trees have buttress roots which flare out from the lower part of the trunk. These brace the tree rather like angle brackets and provide stability, reducing sway in high winds. They are particularly prevalent in tropical rainforests where the soil is poor and the roots are close to the surface. Some tree species have developed root extensions that pop out of soil, in order to get oxygen, when it
4284-414: Is estimated that there are around three trillion mature trees in the world currently. A tree typically has many secondary branches supported clear of the ground by the trunk, which typically contains woody tissue for strength, and vascular tissue to carry materials from one part of the tree to another. For most trees the trunk is surrounded by a layer of bark which serves as a protective barrier. Below
4410-486: Is inelastic. Eventually the growth of a tree slows down and stops and it gets no taller. If damage occurs the tree may in time become hollow. Leaves are structures specialised for photosynthesis and are arranged on the tree in such a way as to maximise their exposure to light without shading each other. They are an important investment by the tree and may be thorny or contain phytoliths , lignins , tannins or poisons to discourage herbivory. Trees have evolved leaves in
4536-424: Is not available in the soil because of excess water. These root extensions are called pneumatophores , and are present, among others, in black mangrove and pond cypress. The main purpose of the trunk is to raise the leaves above the ground, enabling the tree to overtop other plants and outcompete them for light. It also transports water and nutrients from the roots to the aerial parts of the tree, and distributes
4662-458: Is ready to eat when the process is complete, having been tenderised and flavoured by the smoke it has absorbed. In the cold process, the temperature is not allowed to rise above 100 °F (38 °C). The flavour of the food is enhanced but raw food requires further cooking. If it is to be preserved, meat should be cured before cold smoking. Wood has traditionally been used for fuel, especially in rural areas. In less developed nations it may be
4788-428: Is related to climatic conditions; growth normally ceases when conditions are either too cold or too dry. In readiness for the inactive period, trees form buds to protect the meristem , the zone of active growth. Before the period of dormancy, the last few leaves produced at the tip of a twig form scales. These are thick, small and closely wrapped and enclose the growing point in a waterproof sheath. Inside this bud there
4914-407: Is scarce. Frozen ground may limit water availability and conifers are often found in colder places at higher altitudes and higher latitudes than broad leaved trees. In conifers such as fir trees, the branches hang down at an angle to the trunk, enabling them to shed snow. In contrast, broad leaved trees in temperate regions deal with winter weather by shedding their leaves. When the days get shorter and
5040-402: Is that a tree has a woody trunk formed by secondary growth , meaning that the trunk thickens each year by growing outwards, in addition to the primary upwards growth from the growing tip . Under such a definition, herbaceous plants such as palms , bananas and papayas are not considered trees regardless of their height, growth form or stem girth. Certain monocots may be considered trees under
5166-471: Is the first part of a seedling to emerge from the seed during the process of germination . This develops into a taproot which goes straight downwards. Within a few weeks lateral roots branch out of the side of this and grow horizontally through the upper layers of the soil. In most trees, the taproot eventually withers away and the wide-spreading laterals remain. Near the tip of the finer roots are single cell root hairs . These are in immediate contact with
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5292-582: Is the innermost one, unlike in the Faboideae . Some species, like some in the genus Senna , have asymmetric flowers, with one of the lower petals larger than the opposing one, and the style bent to one side. The calyx, corolla, or stamens can be showy in this group. In the Mimosoideae , the flowers are actinomorphic and arranged in globose inflorescences. The petals are small and the stamens, which can be more than just 10, have long, coloured filaments, which are
5418-534: Is the most common family found in tropical rainforests and dry forests of the Americas and Africa. Recent molecular and morphological evidence supports the fact that the Fabaceae is a single monophyletic family. This conclusion has been supported not only by the degree of interrelation shown by different groups within the family compared with that found among the Leguminosae and their closest relations, but also by all
5544-452: Is the only one to develop, so they have unbranched trunks with large spirally arranged leaves. Some of the tree ferns, order Cyatheales , have tall straight trunks, growing up to 20 metres (66 ft), but these are composed not of wood but of rhizomes which grow vertically and are covered by numerous adventitious roots . The number of trees in the world, according to a 2015 estimate, is 3.04 trillion, of which 1.39 trillion (46%) are in
5670-504: The Cretaceous period. These began to displace the conifers during the Tertiary era (66 to 2 million years ago) when forests covered the globe. When the climate cooled 1.5 million years ago and the first of four glacial periods occurred, the forests retreated as the ice advanced. In the interglacials , trees recolonised the land that had been covered by ice, only to be driven back again in
5796-522: The Orchidaceae and Asteraceae , with about 765 genera and nearly 20,000 known species. The five largest genera of the family are Astragalus (over 3,000 species), Acacia (over 1,000 species), Indigofera (around 700 species), Crotalaria (around 700 species), and Mimosa (around 400 species), which constitute about a quarter of all legume species. The c. 19,000 known legume species amount to about 7% of flowering plant species. Fabaceae
5922-466: The Paleogene to become a ubiquitous part of the modern earth's biota , along with many other families belonging to the flowering plants. The Fabaceae have an abundant and diverse fossil record, especially for the Tertiary period. Fossils of flowers, fruit, leaves, wood and pollen from this period have been found in numerous locations. The earliest fossils that can be definitively assigned to
6048-603: The Rosidae clade (as established by the gene molecular phylogeny of rbcL , a gene coding for part of the RuBisCO enzyme in the chloroplast ). This grouping indicates that the predisposition for forming nodules probably only arose once in flowering plants and that it can be considered as an ancestral characteristic that has been conserved or lost in certain lineages. However, such a wide distribution of families and genera within this lineage indicates that nodulation had multiple origins. Of
6174-563: The Tethys seaway during the Palaeogene Period. However, others contend that Africa (or even the Americas ) cannot yet be ruled out as the origin of the family. The current hypothesis about the evolution of the genes needed for nodulation is that they were recruited from other pathways after a polyploidy event. Several different pathways have been implicated as donating duplicated genes to
6300-414: The annual growth rings There may also be rays running at right angles to growth rings. These are vascular rays which are thin sheets of living tissue permeating the wood. Many older trees may become hollow but may still stand upright for many years. Trees do not usually grow continuously throughout the year but mostly have spurts of active expansion followed by periods of rest. This pattern of growth
6426-451: The flowers of one plant to others thereby ensuring pollination. Many Fabaceae species are important sources of pollen and nectar for bees, including for honey production in the beekeeping industry. Example Fabaceae such as alfalfa , and various clovers including white clover and sweet clover , are important sources of nectar and honey for the Western honey bee . Tree In botany ,
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#17328694135796552-458: The fruit of these plants, which are called legumes . Fabaceae range in habit from giant trees (like Koompassia excelsa ) to small annual herbs , with the majority being herbaceous perennials. Plants have indeterminate inflorescences, which are sometimes reduced to a single flower. The flowers have a short hypanthium and a single carpel with a short gynophore , and after fertilization produce fruits that are legumes. The Fabaceae have
6678-399: The legume , pea , or bean family , are a large and agriculturally important family of flowering plants . It includes trees , shrubs , and perennial or annual herbaceous plants , which are easily recognized by their fruit ( legume ) and their compound, stipulate leaves. The family is widely distributed, and is the third-largest land plant family in number of species, behind only
6804-546: The pine ( Pinus species) the bark exudes sticky resin which deters attackers whereas in rubber trees ( Hevea brasiliensis ) it is a milky latex that oozes out. The quinine bark tree ( Cinchona officinalis ) contains bitter substances to make the bark unpalatable. Large tree-like plants with lignified trunks in the Pteridophyta , Arecales , Cycadophyta and Poales such as the tree ferns, palms, cycads and bamboos have different structures and outer coverings. Although
6930-498: The 10 families within the Rosidae, 8 have nodules formed by actinomyces ( Betulaceae , Casuarinaceae , Coriariaceae , Datiscaceae , Elaeagnaceae , Myricaceae , Rhamnaceae and Rosaceae ), and the two remaining families, Ulmaceae and Fabaceae have nodules formed by rhizobia. The rhizobia and their hosts must be able to recognize each other for nodule formation to commence. Rhizobia are specific to particular host species although
7056-525: The 12,000 years since the start of human agriculture, the number of trees worldwide has decreased by 46%. There are approximately 64,100 known tree species in the world. With 43% of all tree species, South America has the highest biodiversity, followed by Eurasia (22%), Africa (16%), North America (15%), and Oceania (11%). In suitable environments, such as the Daintree Rainforest in Queensland , or
7182-603: The English oak ( Quercus robur ) and 306 species of invertebrate on the Tasmanian oak ( Eucalyptus obliqua ). Non-native tree species provide a less biodiverse community, for example in the United Kingdom the sycamore ( Acer pseudoplatanus ), which originates from southern Europe, has few associated invertebrate species, though its bark supports a wide range of lichens, bryophytes and other epiphytes. Trees differ ecologically in
7308-535: The European bay tree ( Laurus nobilis ) and the California bay tree ( Umbellularia californica ) are used for flavouring food. Camellia sinensis , the source of tea, is a small tree but seldom reaches its full height, being heavily pruned to make picking the leaves easier. Wood smoke can be used to preserve food. In the hot smoking process the food is exposed to smoke and heat in a controlled environment. The food
7434-462: The Fabaceae appeared in the early Palaeocene (approximately 65 million years ago). Representatives of the 3 sub-families traditionally recognised as being members of the Fabaceae – Cesalpinioideae, Papilionoideae and Mimosoideae – as well as members of the large clades within these sub-families – such as the genistoides – have been found in periods later, starting between 55 and 50 million years ago. In fact,
7560-536: The Fabaceae. Forisome proteins are found in the sieve tubes of Fabaceae; uniquely they are not dependent on ADT . The order Fabales contains around 7.3% of eudicot species and the greatest part of this diversity is contained in just one of the four families that the order contains: Fabaceae. This clade also includes the families Polygalaceae , Surianaceae and Quillajaceae and its origins date back 94 to 89 million years, although it started its diversification 79 to 74 million years ago. The Fabaceae diversified during
7686-708: The Faboideae, even though diversification within each genus was relatively recent. For instance, Astragalus separated from the Oxytropis 16 to 12 million years ago. In addition, the separation of the aneuploid species of Neoastragalus started 4 million years ago. Inga , another genus of the Papilionoideae with approximately 350 species, seems to have diverged in the last 2 million years. It has been suggested, based on fossil and phylogenetic evidence, that legumes originally evolved in arid and/or semi-arid regions along
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#17328694135797812-571: The Mimosoideae and the Caesalpinioideae commonly bipinnate (e.g. Acacia , Mimosa ). They always have stipules , which can be leaf-like (e.g. Pisum ), thorn-like (e.g. Robinia ) or be rather inconspicuous. Leaf margins are entire or, occasionally, serrate . Both the leaves and the leaflets often have wrinkled pulvini to permit nastic movements . In some species, leaflets have evolved into tendrils (e.g. Vicia ). Many species have leaves with structures that attract ants which protect
7938-577: The ability to take nitrogen gas (N 2 ) out of the air and convert it to a form of nitrogen that is usable to the host plant ( NO 3 or NH 3 ). This process is called nitrogen fixation . The legume, acting as a host, and rhizobia , acting as a provider of usable nitrate, form a symbiotic relationship. Members of the Phaseoleae genus Apios form tubers, which can be edible. The flowers often have five generally fused sepals and five free petals . They are generally hermaphroditic and have
8064-495: The apex (remaining free at the base), forming a boat-like structure called the keel. The stamens are always ten in number, and their filaments can be fused in various configurations, often in a group of nine stamens plus one separate stamen. Various genes in the CYCLOIDEA (CYC)/DICHOTOMA (DICH) family are expressed in the upper (also called dorsal or adaxial) petal; in some species, such as Cadia , these genes are expressed throughout
8190-496: The arrival of warmer weather and the longer days associated with spring in temperate regions, growth starts again. The expanding shoot pushes its way out, shedding the scales in the process. These leave behind scars on the surface of the twig. The whole year's growth may take place in just a few weeks. The new stem is unlignified at first and may be green and downy. The Arecaceae (palms) have their leaves spirally arranged on an unbranched trunk. In some tree species in temperate climates,
8316-437: The bark functions as a protective barrier, it is itself attacked by boring insects such as beetles. These lay their eggs in crevices and the larvae chew their way through the cellulose tissues leaving a gallery of tunnels. This may allow fungal spores to gain admittance and attack the tree. Dutch elm disease is caused by a fungus ( Ophiostoma species) carried from one elm tree to another by various beetles. The tree reacts to
8442-429: The basic legume fruit. The Fabaceae are rarely cyanogenic . Where they are, the cyanogenic compounds are derived from tyrosine , phenylalanine or leucine . They frequently contain alkaloids . Proanthocyanidins can be present either as cyanidin or delphinidine or both at the same time. Flavonoids such as kaempferol , quercitin and myricetin are often present. Ellagic acid has never been found in any of
8568-436: The chloroplast genes rbcL and matK , or the ribosomal spacers ITS ) and cladistic analysis in order to investigate the relationships between the family's different lineages. Fabaceae is consistently recovered as monophyletic . The studies further confirmed that the traditional subfamilies Mimosoideae and Papilionoideae were each monophyletic but both were nested within the paraphyletic subfamily Caesalpinioideae. All
8694-440: The clove tree ( Syzygium aromaticum ). Many trees have flowers rich in nectar which are attractive to bees. The production of forest honey is an important industry in rural areas of the developing world where it is undertaken by small-scale beekeepers using traditional methods. The flowers of the elder ( Sambucus ) are used to make elderflower cordial and petals of the plum ( Prunus spp. ) can be candied. Sassafras oil
8820-560: The compound 3-nitropropanoic acid (3-NPA, beta-nitropropionic acid ). The free acid 3-NPA is an irreversible inhibitor of mitochondrial respiration , and thus the compound inhibits the tricarboxylic acid cycle . This inhibition caused by 3-NPA is especially toxic to nerve cells and represents a very general toxic mechanism suggesting a profound ecological importance due to the big number of species producing this compound and its derivatives. A second and closely related class of secondary metabolites that occur in many species of leguminous plants
8946-465: The cone for years waiting for a trigger event to liberate it. Fire stimulates release and germination of seeds of the jack pine , and also enriches the forest floor with wood ash and removes competing vegetation. Similarly, a number of angiosperms including Acacia cyclops and Acacia mangium have seeds that germinate better after exposure to high temperatures. The single extant species of Ginkgophyta ( Ginkgo biloba ) has fleshy seeds produced at
9072-536: The different approaches yielded similar results regarding the relationships between the family's main clades. Following extensive discussion in the legume phylogenetics community, the Legume Phylogeny Working Group reclassified Fabaceae into six subfamilies, which necessitated the segregation of four new subfamilies from Caesalpinioideae and merging Caesapinioideae sensu stricto with the former subfamily Mimosoideae. The exact branching order of
9198-552: The different subfamilies is still unresolved. Polygalaceae ( outgroup ) Surianaceae (outgroup) Quillajaceae (outgroup) Cercidoideae Detarioideae Duparquetioideae Dialioideae Caesalpinioideae Faboideae The Fabaceae are placed in the order Fabales according to most taxonomic systems, including the APG III system . The family now includes six subfamilies: The Fabaceae have an essentially worldwide distribution, being found everywhere except Antarctica and
9324-424: The ease with which they can be found by herbivores. Tree apparency varies with a tree's size and semiochemical content, and with the extent to which it is concealed by nonhost neighbours from its insect pests . In ecosystems such as mangrove swamps, trees play a role in developing the habitat, since the roots of the mangrove trees reduce the speed of flow of tidal currents and trap water-borne sediment, reducing
9450-645: The ends of short branches on female trees, and Gnetum , a tropical and subtropical group of gymnosperms produce seeds at the tip of a shoot axis. The earliest trees were tree ferns , horsetails and lycophytes , which grew in forests in the Carboniferous period. The first tree may have been Wattieza , fossils of which were found in New York state in 2007 dating back to the Middle Devonian (about 385 million years ago). Prior to this discovery, Archaeopteris
9576-461: The far north of the northern hemisphere is moist taiga or northern coniferous forest (also called boreal forest). Taiga is the world's largest land biome , forming 29% of the world's forest cover. The long cold winter of the far north is unsuitable for plant growth and trees must grow rapidly in the short summer season when the temperature rises and the days are long. Light is very limited under their dense cover and there may be little plant life on
9702-432: The flower, producing a radially symmetrical flower. The ovary most typically develops into a legume . A legume is a simple dry fruit that usually dehisces (opens along a seam) on two sides. A common name for this type of fruit is a "pod", although that can also be applied to a few other fruit types. A few species have evolved samarae , loments , follicles , indehiscent legumes, achenes , drupes , and berries from
9828-480: The food produced by the leaves to all other parts, including the roots. In the case of angiosperms and gymnosperms, the outermost layer of the trunk is the bark , mostly composed of dead cells of phellem (cork). It provides a thick, waterproof covering to the living inner tissue. It protects the trunk against the elements, disease, animal attack and fire. It is perforated by a large number of fine breathing pores called lenticels , through which oxygen diffuses. Bark
9954-401: The forest floor, although fungi may abound. Similar woodland is found on mountains where the altitude causes the average temperature to be lower thus reducing the length of the growing season. Where rainfall is relatively evenly spread across the seasons in temperate regions, temperate broadleaf and mixed forest typified by species like oak, beech, birch and maple is found. Temperate forest
10080-425: The fruits and either discard the seeds, or swallow them so they pass through the gut to be deposited in the animal's droppings well away from the parent tree. The germination of some seeds is improved when they are processed in this way. Nuts may be gathered by animals such as squirrels that cache any not immediately consumed. Many of these caches are never revisited; the nut-casing softens with rain and frost, and
10206-429: The genera or species analysed. Sugars are transported within the plants in the form of sucrose . C3 photosynthesis has been found in a wide variety of genera. The family has also evolved a unique chemistry. Many legumes contain toxic and indigestible substances, antinutrients , which may be removed through various processing methods. Pterocarpans are a class of molecules (derivatives of isoflavonoids ) found only in
10332-480: The ground underneath trees there is shade, and often there is undergrowth, leaf litter , and decaying wood that provide other habitat. Trees stabilise the soil, prevent rapid run-off of rain water, help prevent desertification, have a role in climate control and help in the maintenance of biodiversity and ecosystem balance. Many species of tree support their own specialised invertebrates . In their natural habitats, 284 different species of insect have been found on
10458-557: The ground, the roots branch and spread out widely; they serve to anchor the tree and extract moisture and nutrients from the soil . Above ground, the branches divide into smaller branches and shoots. The shoots typically bear leaves, which capture light energy and convert it into sugars by photosynthesis , providing the food for the tree's growth and development. Trees usually reproduce using seeds . Flowering plants have their seeds inside fruits, while conifers carry their seeds in cones, and tree ferns produce spores instead. Trees play
10584-421: The ground. Trees use a variety of methods of seed dispersal . Some rely on wind, with winged or plumed seeds. Others rely on animals, for example with edible fruits. Others again eject their seeds (ballistic dispersal), or use gravity so that seeds fall and sometimes roll. Seeds are the primary way that trees reproduce and their seeds vary greatly in size and shape. Some of the largest seeds come from trees, but
10710-413: The growth of the fungus by blocking off the xylem tissue carrying sap upwards and the branch above, and eventually the whole tree, is deprived of nourishment and dies. In Britain in the 1990s, 25 million elm trees were killed by this disease. The innermost layer of bark is known as the phloem and this is involved in the transport of the sap containing the sugars made by photosynthesis to other parts of
10836-447: The heartwood are blocked in some species. Heartwood is usually darker in colour than the sapwood. It is the dense central core of the trunk giving it rigidity. Three quarters of the dry mass of the xylem is cellulose , a polysaccharide , and most of the remainder is lignin, a complex polymer . A transverse section through a tree trunk or a horizontal core will show concentric circles of lighter or darker wood – tree rings. These rings are
10962-452: The high Arctic. The trees are often found in tropical regions, while the herbaceous plants and shrubs are predominant outside the tropics. Biological nitrogen fixation (BNF, performed by the organisms called diazotrophs ) is a very old process that probably originated in the Archean eon when the primitive atmosphere lacked oxygen . It is only carried out by Euryarchaeota and just 6 of
11088-428: The infection thread development in that infection threads grow in a polar manner that is similar to a pollen tubes polar growth towards the ovules. Both pathways include the same type of enzymes, pectin-degrading cell wall enzymes. The enzymes needed to reduce nitrogen, nitrogenases, require a substantial input of ATP but at the same time are sensitive to free oxygen. To meet the requirements of this paradoxical situation,
11214-411: The inserted spigots; the sap is then heated to concentrate the flavour. Similarly in northern Europe the spring rise in the sap of the silver birch ( Betula pendula ) is tapped and collected, either to be drunk fresh or fermented into an alcoholic drink. In Alaska, the sap of the sweet birch ( Betula lenta ) is made into a syrup with a sugar content of 67%. Sweet birch sap is more dilute than maple sap;
11340-400: The inside. The newly created xylem is the sapwood . It is composed of water-conducting cells and associated cells which are often living, and is usually pale in colour. It transports water and minerals from the roots to the upper parts of the tree. The oldest, inner part of the sapwood is progressively converted into heartwood as new sapwood is formed at the cambium. The conductive cells of
11466-528: The largest tree, Sequoiadendron giganteum , produces one of the smallest tree seeds. The great diversity in tree fruits and seeds reflects the many different ways that tree species have evolved to disperse their offspring. For a tree seedling to grow into an adult tree it needs light. If seeds only fell straight to the ground, competition among the concentrated saplings and the shade of the parent would likely prevent it from flourishing. Many seeds such as birch are small and have papery wings to aid dispersal by
11592-461: The main Cesalpinioideae clades have been estimated as between 56 and 34 million years and the basal group of the Mimosoideae as 44 ± 2.6 million years. The division between Mimosoideae and Faboideae is dated as occurring between 59 and 34 million years ago and the basal group of the Faboideae as 58.6 ± 0.2 million years ago. It has been possible to date the divergence of some of the groups within
11718-409: The mixed podocarp and broadleaf forest of Ulva Island, New Zealand , forest is the more-or-less stable climatic climax community at the end of a plant succession, where open areas such as grassland are colonised by taller plants, which in turn give way to trees that eventually form a forest canopy. In cool temperate regions, conifers often predominate; a widely distributed climax community in
11844-580: The more than 50 phyla of bacteria . Some of these lineages co-evolved together with the flowering plants establishing the molecular basis of a mutually beneficial symbiotic relationship. BNF is carried out in nodules that are mainly located in the root cortex, although they are occasionally located in the stem as in Sesbania rostrata . The spermatophytes that co-evolved with actinorhizal diazotrophs ( Frankia ) or with rhizobia to establish their symbiotic relationship belong to 11 families contained within
11970-519: The next glacial period. Trees are an important part of the terrestrial ecosystem , providing essential habitats including many kinds of forest for communities of organisms. Epiphytic plants such as ferns , some mosses, liverworts, orchids and some species of parasitic plants (e.g., mistletoe ) hang from branches; these along with arboreal lichens, algae, and fungi provide micro-habitats for themselves and for other organisms, including animals. Leaves, flowers and fruits are seasonally available. On
12096-420: The old lineages of flowering plants called basal angiosperms or paleodicots ; these include Amborella , Magnolia , nutmeg and avocado , while trees such as bamboo, palms and bananas are monocots . Wood gives structural strength to the trunk of most types of tree; this supports the plant as it grows larger. The vascular system of trees allows water, nutrients and other chemicals to be distributed around
12222-409: The pathways need for nodulation. The main donors to the pathway were the genes associated with the arbuscular mycorrhiza symbiosis genes, the pollen tube formation genes and the haemoglobin genes. One of the main genes shown to be shared between the arbuscular mycorrhiza pathway and the nodulation pathway is SYMRK and it is involved in the plant-bacterial recognition. The pollen tube growth is similar to
12348-585: The plant and reduce water loss. Both the production of wood and the production of cork are forms of secondary growth. Trees are either evergreen , having foliage that persists and remains green throughout the year, or deciduous , shedding their leaves at the end of the growing season and then having a dormant period without foliage. Most conifers are evergreens, but larches ( Larix and Pseudolarix ) are deciduous, dropping their needles each autumn, and some species of cypress ( Glyptostrobus , Metasequoia and Taxodium ) shed small leafy shoots annually in
12474-431: The plant from herbivore insects (a form of mutualism ). Extrafloral nectaries are common among the Mimosoideae and the Caesalpinioideae, and are also found in some Faboideae (e.g. Vicia sativa ). In some Acacia , the modified hollow stipules are inhabited by ants and are known as domatia . Many Fabaceae host bacteria in their roots within structures called root nodules . These bacteria, known as rhizobia , have
12600-409: The plant, and without it trees would not be able to grow as large as they do. Trees need to draw water high up the stem through the xylem from the roots by capillary action , as water continually evaporates from the leaves in the process of transpiration . If insufficient water is available the leaves will die. The three main parts of trees include the root, stem, and leaves; they are integral parts of
12726-436: The plants express a type of haemoglobin called leghaemoglobin that is believed to be recruited after a duplication event. These three genetic pathways are believed to be part of a gene duplication event then recruited to work in nodulation. The phylogeny of the legumes has been the object of many studies by research groups from around the world. These studies have used morphology, DNA data (the chloroplast intron trnL ,
12852-858: The process. Legumes are commonly used as natural fertilizers. Some legume species perform hydraulic lift , which makes them ideal for intercropping . Farmed legumes can belong to numerous classes, including forage , grain , blooms, pharmaceutical/industrial, fallow/green manure and timber species, with most commercially farmed species filling two or more roles simultaneously. There are of two broad types of forage legumes. Some, like alfalfa , clover , vetch , and Arachis , are sown in pasture and grazed by livestock. Other forage legumes such as Leucaena or Albizia are woody shrub or tree species that are either broken down by livestock or regularly cut by humans to provide fodder . Grain legumes are cultivated for their seeds , and are also called pulses . The seeds are used for human and animal consumption or for
12978-656: The production of indigo , Acacia , for gum arabic , and Derris , for the insecticide action of rotenone , a compound it produces. Fallow or green manure legume species are cultivated to be tilled back into the soil to exploit the high nitrogen levels found in most legumes. Numerous legumes are farmed for this purpose, including Leucaena , Cyamopsis and Sesbania . Various legume species are farmed for timber production worldwide, including numerous Acacia species, Dalbergia species, and Castanospermum australe . Melliferous plants offer nectar to bees and other insects to encourage them to carry pollen from
13104-709: The production of oils for industrial uses. Grain legumes include both herbaceous plants like beans , lentils , lupins , peas and peanuts , and trees such as carob , mesquite and tamarind . Lathyrus tuberosus , once extensively cultivated in Europe, forms tubers used for human consumption. Bloom legume species include species such as lupin , which are farmed commercially for their blooms, and thus are popular in gardens worldwide. Laburnum , Robinia , Gleditsia (honey locust), Acacia , Mimosa , and Delonix are ornamental trees and shrubs . Industrial farmed legumes include Indigofera , cultivated for
13230-404: The recent phylogenetic studies based on DNA sequences. These studies confirm that the Fabaceae are a monophyletic group that is closely related to the families Polygalaceae , Surianaceae and Quillajaceae and that they belong to the order Fabales . Along with the cereals , some fruits and tropical roots, a number of Leguminosae have been a staple human food for millennia and their use
13356-437: The rest, many are gymnosperms or softwood trees; these include conifers , cycads , ginkgophytes and gnetales , which produce seeds which are not enclosed in fruits, but in open structures such as pine cones , and many have tough waxy leaves, such as pine needles. Most angiosperm trees are eudicots , the "true dicotyledons", so named because the seeds contain two cotyledons or seed leaves. There are also some trees among
13482-428: The roots and helps protect the trees against predators and pathogens. It can also limit damage done to a tree by pollution as the fungus accumulate heavy metals within its tissues. Fossil evidence shows that roots have been associated with mycorrhizal fungi since the early Paleozoic , four hundred million years ago, when the first vascular plants colonised dry land. Some trees such as Alder ( Alnus species) have
13608-464: The seeds on the surface of water. Mangroves often grow in water and some species have buoyant fruits with seeds that start germinating before they detach from the parent tree. These float on the water and may become lodged on emerging mudbanks and successfully take root. Other seeds, such as apple pips and plum stones, have fleshy receptacles and smaller fruits like hawthorns have seeds enclosed in edible tissue; animals including mammals and birds eat
13734-425: The showiest part of the flower. All of the flowers in an inflorescence open at once. In the Faboideae , the flowers are zygomorphic, and have a specialized structure . The upper petal, called the banner or standard, is large and envelops the rest of the petals in bud, often reflexing when the flower blooms. The two adjacent petals, the wings, surround the two bottom petals. The two bottom petals are fused together at
13860-434: The soil particles and can absorb water and nutrients such as potassium in solution. The roots require oxygen to respire and only a few species such as mangroves and the pond cypress ( Taxodium ascendens ) can live in permanently waterlogged soil. In the soil, the roots encounter the hyphae of fungi. Many of these are known as mycorrhiza and form a mutualistic relationship with the tree roots. Some are specific to
13986-471: The start of the dry season. Many deciduous trees flower before the new leaves emerge. A few trees do not have true leaves but instead have structures with similar external appearance such as Phylloclades – modified stem structures – as seen in the genus Phyllocladus . Trees can be pollinated either by wind or by animals, mostly insects. Many angiosperm trees are insect pollinated. Wind pollination may take advantage of increased wind speeds high above
14112-571: The subfamily Papilionoideae: indeterminate (with the meristem retained), determinate (without meristem) and the type included in Aeschynomene . The latter two are thought to be the most modern and specialised type of nodule as they are only present in some lines of the subfamily Papilionoideae. Even though nodule formation is common in the two monophyletic subfamilies Papilionoideae and Mimosoideae they also contain species that do not form nodules. The presence or absence of nodule-forming species within
14238-413: The surviving seeds germinate in the spring. Pine cones may similarly be hoarded by red squirrels , and grizzly bears may help to disperse the seed by raiding squirrel caches. The seeds of conifers, the largest group of gymnosperms, are enclosed in a cone and most species have seeds that are light and papery that can be blown considerable distances once free from the cone. Sometimes the seed remains in
14364-661: The temperature begins to decrease, the leaves no longer make new chlorophyll and the red and yellow pigments already present in the blades become apparent. Synthesis in the leaf of a plant hormone called auxin also ceases. This causes the cells at the junction of the petiole and the twig to weaken until the joint breaks and the leaf floats to the ground. In tropical and subtropical regions, many trees keep their leaves all year round. Individual leaves may fall intermittently and be replaced by new growth but most leaves remain intact for some time. Other tropical species and those in arid regions may shed all their leaves annually, such as at
14490-654: The three sub-families indicates that nodule formation has arisen several times during the evolution of the Fabaceae and that this ability has been lost in some lineages. For example, within the genus Acacia , a member of the Mimosoideae, A. pentagona does not form nodules, while other species of the same genus readily form nodules, as is the case for Acacia senegal , which forms both rapidly and slow growing rhizobial nodules. A large number of species within many genera of leguminous plants, e.g. Astragalus , Coronilla , Hippocrepis , Indigofera , Lotus , Securigera and Scorpiurus , produce chemicals that derive from
14616-408: The tree, but some tree species have evolved roots that are aerial . The common purposes for aerial roots may be of two kinds, to contribute to the mechanical stability of the tree, and to obtain oxygen from air. An instance of mechanical stability enhancement is the red mangrove that develops prop roots that loop out of the trunk and branches and descend vertically into the mud. A similar structure
14742-432: The tree. It is a soft spongy layer of living cells, some of which are arranged end to end to form tubes. These are supported by parenchyma cells which provide padding and include fibres for strengthening the tissue. Inside the phloem is a layer of undifferentiated cells one cell thick called the vascular cambium layer. The cells are continually dividing, creating phloem cells on the outside and wood cells known as xylem on
14868-492: The tropics or sub-tropics , 0.61 trillion (20%) in the temperate zones , and 0.74 trillion (24%) in the coniferous boreal forests . The estimate is about eight times higher than previous estimates, and is based on tree densities measured on over 400,000 plots. It remains subject to a wide margin of error, not least because the samples are mainly from Europe and North America. The estimate suggests that about 15 billion trees are cut down annually and about 5 billion are planted. In
14994-403: The vascular system which interconnects all the living cells. In trees and other plants that develop wood, the vascular cambium allows the expansion of vascular tissue that produces woody growth. Because this growth ruptures the epidermis of the stem, woody plants also have a cork cambium that develops among the phloem. The cork cambium gives rise to thickened cork cells to protect the surface of
15120-429: The water depth and creating suitable conditions for further mangrove colonisation. Thus mangrove swamps tend to extend seawards in suitable locations. Mangrove swamps also provide an effective buffer against the more damaging effects of cyclones and tsunamis. Trees are the source of many of the world's best known fleshy fruits. Apples, pears, plums, cherries and citrus are all grown commercially in temperate climates and
15246-541: The wide variety of edible vegetables they represent and due to the variety of uses they can be put to: in horticulture and agriculture, as a food, for the compounds they contain that have medicinal uses and for the oil and fats they contain that have a variety of uses. The history of legumes is tied in closely with that of human civilization, appearing early in Asia , the Americas (the common bean , several varieties) and Europe (broad beans) by 6,000 BCE , where they became
15372-437: The wind. Ash trees and maples have larger seeds with blade shaped wings which spiral down to the ground when released. The kapok tree has cottony threads to catch the breeze. The flame tree Delonix regia shoots its seeds through the air when the two sides of its long pods crack apart explosively on drying. The miniature cone-like catkins of alder trees produce seeds that contain small droplets of oil that help disperse
15498-465: The world, forests are shrinking as trees are cleared to increase the amount of land available for agriculture. Because of their longevity and usefulness, trees have always been revered, with sacred groves in various cultures, and they play a role in many of the world's mythologies . Although "tree" is a common word, there is no universally recognised precise definition of what a tree is, either botanically or in common language. In its broadest sense,
15624-769: The world, fruit is gathered from forest trees for consumption. Many trees bear edible nuts which can loosely be described as being large, oily kernels found inside a hard shell. These include coconuts ( Cocos nucifera ), Brazil nuts ( Bertholletia excelsa ), pecans ( Carya illinoinensis ), hazel nuts ( Corylus ), almonds ( Prunus dulcis ), walnuts ( Juglans regia ), pistachios ( Pistacia vera ) and many others. They are high in nutritive value and contain high-quality protein, vitamins and minerals as well as dietary fibre. A variety of nut oils are extracted by pressing for culinary use; some such as walnut, pistachio and hazelnut oils are prized for their distinctive flavours, but they tend to spoil quickly. In temperate climates there
15750-457: The world, including Cytisus scoparius (broom), Robinia pseudoacacia (black locust) , Ulex europaeus (gorse), Pueraria montana (kudzu), and a number of Lupinus species. The name 'Fabaceae' comes from the defunct genus Faba , now included in Vicia . The term "faba" comes from Latin, and appears to simply mean "bean". Leguminosae is an older name still considered valid, and refers to
15876-450: Was the earliest known tree. Both of these reproduced by spores rather than seeds and are considered to be links between ferns and the gymnosperms which evolved in the Triassic period. The gymnosperms include conifers, cycads, gnetales and ginkgos and these may have appeared as a result of a whole genome duplication event which took place about 319 million years ago. Ginkgophyta was once
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