In botany, a tree is a perennial plant with an elongated stem, or trunk, supporting branches and leaves in most species. 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. Trees are not a taxonomic group but include a variety of plant species that have independently evolved a woody trunk and branches as a way to tower above other plants to compete for sunlight. Trees tend to be long-lived, some reaching several thousand years old. In wider definitions, the taller palms, tree ferns and bamboos are trees. Trees have been in existence for 370 million years, it is estimated. A tree has many secondary branches supported clear of the ground by the trunk; this trunk contains woody tissue for strength, vascular tissue to carry materials from one part of the tree to another. For most trees it is surrounded by a layer of bark. Below the ground, the roots spread out widely. Above ground, the branches divide into smaller shoots.
The shoots bear leaves, which capture light energy and convert it into sugars by photosynthesis, providing the food for the tree's growth and development. Trees reproduce using seeds. Flowers and fruit may be present, but some trees, such as conifers, instead have pollen cones and seed cones. Palms and bamboos produce seeds, but tree ferns produce spores instead. Trees play a significant role in 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 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, fruit for food as well as having many other uses. In parts of 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, they play a role in many of the world's mythologies.
Although "tree" is a term of common parlance, there is no universally recognised precise definition of what a tree is, either botanically or in common language. In its broadest sense, 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 typically defined by height, with smaller plants from 0.5 to 10 m 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 applied narrower definition 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 and papayas are not considered trees regardless of their height, growth form or stem girth. Certain monocots may be considered trees under a looser definition.
Aside from structural definitions, trees are defined by use. The tree growth habit is an evolutionary adaptation found in different groups of plants: by growing taller, trees are able to compete better for sunlight. Trees tend 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 a similar growth form, by growing larger and having a single main stem. The tree form has evolved separately in unrelated classes of plants in response to similar environmental challenges, making it 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 and many of these areas have not yet been surveyed by botanists, making tree diversity and ranges poorly known.
The majority of tree species are angiosperms. There are about 1000 species of gymnosperm trees, including conifers, cycads and gnetales. Most angiosperm trees are eudicots, the "true dicotyledons", so named because the seeds contain two cotyledons or seed leaves. There are some trees among the old lineages of flowering plants called basal angiosperms or paleodicots. Wood gives structural strength to the trunk of most types of tree; the vascular system of trees allows water and other chemicals to be di
The Sapotaceae are a family of flowering plants belonging to the order Ericales. The family includes about 800 species of evergreen shrubs in around 65 genera, their distribution is pantropical. Many species produce edible fruits, or white blood-sap, used to cleanse dirt and manually, while others have other economic uses. Species noted for their edible fruits include Manilkara, Chrysophyllum cainito, Pouteria. Vitellaria paradoxa is the source of an oil-rich nut, the source of edible shea butter, the major lipid source for many African ethnic groups and is used in traditional and Western cosmetics and medications. The'miracle fruit' Synsepalum dulcificum is in the Sapotaceae. Trees of the genus Palaquium produce an important latex with a wide variety of uses; the seeds of the tree Argania spinosa produce an edible oil, traditionally harvested in Morocco. The family name is derived from zapote, a Mexican vernacular name for one of the plants and Latinised by Linnaeus as sapota, a name now treated as a synonym of Manilkara
In botany, an evergreen is a plant that has leaves throughout the year that are always green. This is true if the plant retains its foliage only in warm climates, contrasts with deciduous plants, which lose their foliage during the winter or dry season. There are many different kinds of both trees and shrubs. Evergreens include: most species of conifers, but not all live oak, "ancient" gymnosperms such as cycads most angiosperms from frost-free climates, such as eucalypts and rainforest trees clubmosses and relativesThe Latin binomial term sempervirens, meaning "always green", refers to the evergreen nature of the plant, for instance Cupressus sempervirens Lonicera sempervirens Sequoia sempervirens Leaf persistence in evergreen plants varies from a few months to several decades. Deciduous trees shed their leaves as an adaptation to a cold or dry/wet season. Evergreen trees do lose leaves, but each tree loses its leaves and not all at once. Most tropical rainforest plants are considered to be evergreens, replacing their leaves throughout the year as the leaves age and fall, whereas species growing in seasonally arid climates may be either evergreen or deciduous.
Most warm temperate climate plants are evergreen. In cool temperate climates, fewer plants are evergreen, with a predominance of conifers, as few evergreen broadleaf plants can tolerate severe cold below about −26 °C. In areas where there is a reason for being deciduous, e.g. a cold season or dry season, being evergreen is an adaptation to low nutrient levels. Deciduous trees lose nutrients. In warmer areas, species such as some pines and cypresses grow on disturbed ground. In Rhododendron, a genus with many broadleaf evergreens, several species grow in mature forests but are found on acidic soil where the nutrients are less available to plants. In taiga or boreal forests, it is too cold for the organic matter in the soil to decay so the nutrients in the soil are less available to plants, thus favouring evergreens. In temperate climates, evergreens can reinforce their own survival; these conditions favour the growth of more evergreens and make it more difficult for deciduous plants to persist.
In addition, the shelter provided by existing evergreen plants can make it easier for younger evergreen plants to survive cold and/or drought. Semi-deciduous Helen Ingersoll. "Evergreens". Encyclopedia Americana
South Florida is a geographic and cultural region that comprises Florida's southernmost counties, including Miami-Dade and Palm Beach. It is the fourth most populous urban agglomeration in the United States, it is one of Florida's three most common "directional" regions, the others being Central Florida and North Florida. It includes the populous Miami metropolitan area, the Everglades, the Florida Keys, Treasure Coast, other localities. South Florida is the only part of the continental United States with a tropical climate; as with all vernacular regions, South Florida has no official boundaries or status and is defined differently by different sources at different times. A 2007 study of Florida's regions by Ary Lamme and Raymond K. Oldakowski found that Floridians surveyed identified "South Florida" as comprising the southernmost sections of peninsular Florida; that area includes the Miami metropolitan area, the Florida Keys included in Monroe county, the interior region known as the Glades.
Additionally, Southwest Florida, representing the state's southern Gulf Coast, has emerged as a directional vernacular region. Some respondents from as far northwest as the southern Tampa Bay area identified their region as being in South Florida rather than Southwest or Central Florida. However, the University of South Florida, founded in 1956, is located in Tampa. At that time, prior to the changes brought by the Florida Constitution of 1968, south Florida was much less important politically, the term was used more loosely. Tampa is not considered part of south Florida. Enterprise Florida, the state's economic development agency, identifies "Southeast Florida" as one of eight economic regions used by the agency and other state and outside entities, including the Florida Department of Transportation; some entities alternately designate this region "South Florida". Its definition includes much of the same territory as Lamme and Oldakowski's report as well as additional area, it includes Monroe County and the three metropolitan counties of Miami-Dade and Palm Beach.
The demographics of South Florida residents can be segmented as following: Over 87.2% of all foreigners residing in South Florida come from Latin America. Largest cities in South Florida by population: The Miami accent is a regional accent of the American English dialect spoken in South Florida in Miami-Dade, Palm Beach, Monroe counties; the accent was born in central Miami, but has expanded to the rest of South Florida in the decades since the 1960s. The Miami accent is most prevalent in American-born South Floridian youth; the Miami accent is based on a standard American accent but with some changes similar to dialects in the Mid-Atlantic Unlike Virginia Piedmont, Coastal Southern American, Northeast American dialects, the "Miami accent" is rhotic. Lamme and Oldakowski identify several demographic and cultural elements that characterize South Florida and distinguish it from other areas of the state. Many of its differences appear to be driven by its proportionately higher level of migration from the northern U.
S. states and from the Caribbean and Latin America in the densely populated Miami area. Politically, South Florida is more liberal than the rest of the state. While less than 10% of people in either North or Central Florida felt their area was liberal, over a third of South Floridians described their region as such. 38% characterized the area as conservative. This tracks with South Florida's demographics, Lamme and Oldakowski's findings parallel Barney Warf and Cynthia Waddell's research on Florida's political geography during the 2000 Presidential election; the economy in South Florida is similar to that in Central Florida. Compared to the more diversified economy in North Florida, tourism is by far the most significant industry in South and Central Florida, with a much smaller but vibrant agricultural industry. Lamme and Oldakowski's survey found some cultural indicators distinguishing South Florida. South Florida is the only region of the state where ethnic foods are as popular as general American cuisine.
Additionally, while there was little geographical variation for most styles of music, there was regional variation for both country and Latin music. Country was less popular in South Florida than in North or Central Florida, while Latin was more popular than in the other regions; the Anthony J. Catanese Center for Urban and Environmental Solutions at Florida Atlantic University notes the unusual growth pattern of South Florida. Unlike many areas with centralized cities surrounded by development, most of South Florida is preserved natural area and designated agricultural reserves, with development restricted to a dense, narrow strip along the coast; the developed area is urbanized and continuous and decentralized, with no particular dominant core cities. The center projects this pattern to continue in the future. Over time, there have been numerous proposals for partitioning the state of Florida to form a separate state of South Florida; such proposals have been made as political statement rather than serious attempts at secession.
Reasons stated are cultural, ethnic and financial frustrations with the state government in Tallahassee, in North Florida. In 2008, the North Lauderd
A seed is an embryonic plant enclosed in a protective outer covering. The formation of the seed is part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm plants. Seeds are the product of the ripened ovule, after fertilization by pollen and some growth within the mother plant; the embryo is developed from the seed coat from the integuments of the ovule. Seeds have been an important development in the reproduction and success of gymnosperm and angiosperm plants, relative to more primitive plants such as ferns and liverworts, which do not have seeds and use water-dependent means to propagate themselves. Seed plants now dominate biological niches on land, from forests to grasslands both in hot and cold climates; the term "seed" has a general meaning that antedates the above – anything that can be sown, e.g. "seed" potatoes, "seeds" of corn or sunflower "seeds". In the case of sunflower and corn "seeds", what is sown is the seed enclosed in a shell or husk, whereas the potato is a tuber.
Many structures referred to as "seeds" are dry fruits. Plants producing berries are called baccate. Sunflower seeds are sometimes sold commercially while still enclosed within the hard wall of the fruit, which must be split open to reach the seed. Different groups of plants have other modifications, the so-called stone fruits have a hardened fruit layer fused to and surrounding the actual seed. Nuts are the one-seeded, hard-shelled fruit of some plants with an indehiscent seed, such as an acorn or hazelnut. Seeds are produced in several related groups of plants, their manner of production distinguishes the angiosperms from the gymnosperms. Angiosperm seeds are produced in a hard or fleshy structure called a fruit that encloses the seeds for protection in order to secure healthy growth; some fruits have layers of both fleshy material. In gymnosperms, no special structure develops to enclose the seeds, which begin their development "naked" on the bracts of cones. However, the seeds do become covered by the cone scales.
Seed production in natural plant populations varies from year to year in response to weather variables and diseases, internal cycles within the plants themselves. Over a 20-year period, for example, forests composed of loblolly pine and shortleaf pine produced from 0 to nearly 5 million sound pine seeds per hectare. Over this period, there were six bumper, five poor, nine good seed crops, when evaluated for production of adequate seedlings for natural forest reproduction. Angiosperm seeds consist of three genetically distinct constituents: the embryo formed from the zygote, the endosperm, triploid, the seed coat from tissue derived from the maternal tissue of the ovule. In angiosperms, the process of seed development begins with double fertilization, which involves the fusion of two male gametes with the egg cell and the central cell to form the primary endosperm and the zygote. Right after fertilization, the zygote is inactive, but the primary endosperm divides to form the endosperm tissue.
This tissue becomes the food the young plant will consume until the roots have developed after germination. After fertilization the ovules develop into the seeds; the ovule consists of a number of components: The funicle or seed stalk which attaches the ovule to the placenta and hence ovary or fruit wall, at the pericarp. The nucellus, the remnant of the megasporangium and main region of the ovule where the megagametophyte develops; the micropyle, a small pore or opening in the apex of the integument of the ovule where the pollen tube enters during the process of fertilization. The chalaza, the base of the ovule opposite the micropyle, where integument and nucellus are joined together; the shape of the ovules as they develop affects the final shape of the seeds. Plants produce ovules of four shapes: the most common shape is called anatropous, with a curved shape. Orthotropous ovules are straight with all the parts of the ovule lined up in a long row producing an uncurved seed. Campylotropous ovules have a curved megagametophyte giving the seed a tight "C" shape.
The last ovule shape is called amphitropous, where the ovule is inverted and turned back 90 degrees on its stalk. In the majority of flowering plants, the zygote's first division is transversely oriented in regards to the long axis, this establishes the polarity of the embryo; the upper or chalazal pole becomes the main area of growth of the embryo, while the lower or micropylar pole produces the stalk-like suspensor that attaches to the micropyle. The suspensor absorbs and manufactures nutrients from the endosperm that are used during the embryo's growth; the main components of the embryo are: The cotyledons, the seed leaves, attached to the embryonic axis. There may be two; the cotyledons are the source of nutrients in the non-endospermic dicotyledons, in which case they replace the endosperm, are thick and leathery. In endospermic seeds the cotyledons are papery. Dicotyledons have the point of attachment opposite one another on the axis; the epicotyl, the embryonic axis above the point of attachment of the cotyledon.
The plumule, the tip of the epicotyl, has a feathery appearance due to the presence of young leaf primordia at the apex, will become the shoot upon germination. The hypocotyl, the embryonic axis below the point of attachment of the cotyledon, connecting the epicotyl and the radicle, being the stem-root transition zone; the radicle, the basal tip of the hy
In the APG IV system for the classification of flowering plants, the name asterids denotes a clade. Common examples include the forget-me-nots, the common sunflower, morning glory and sweet potato, lavender, olive, honeysuckle, ash tree, snapdragon, psyllium, garden sage, table herbs such as mint and rosemary, rainforest trees such as Brazil nut. Most of the taxa belonging to this clade had been referred to the Asteridae in the Cronquist system and to the Sympetalae in earlier systems; the name asterids resembles the earlier botanical name but is intended to be the name of a clade rather than a formal ranked name, in the sense of the ICBN. The phylogenetic tree presented hereafter has been proposed by the APG IV project. Genetic analysis carried out after APG II maintains that the sister to all other asterids are the Cornales. A second order that split from the base of the asterids are the Ericales; the remaining orders cluster into two clades, the lamiids and the campanulids. The structure of both of these clades has changed in APG III.
In APG III system, the following clades were renamed: euasterids I → lamiids euasterids II → campanulids Asterids in Stevens, P. F.. Angiosperm Phylogeny Website. Version 7, May 2006
Sapote is a term for a soft, edible fruit. The word is incorporated into the common names of several unrelated fruit-bearing plants native to Mexico, Central America and northern parts of South America, it is known in Caribbean English as soapapple. Some but not all sapotes come from the family Sapotaceae: Sapodilla called naseberry is native to Mexico, Nicaragua, El Salvador; the Sapotaceae were named after a synonym of this species. Yellow sapote is native to Central America. Mamey sapote is from southern Mexico to northern South America. Green sapote is native to lowland southern Mexico. Sapotes from the Ebenaceae family include: Black sapote, from eastern Mexico south to Colombia, is the original Aztec tzapotl. Chapote is native to the lower Rio Grande valley region in Texas and Mexico White sapote is native to northern and central Mexico, Costa Rica, El Salvador and Guatemala. South American sapote is native to the Amazon rainforests of Brazil, Colombia and Peru