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Elaeis

Elaeis

Elaeis guineensis
Elaeis oleifera The oil palms (Elaeis) coomprise two species of the Arecaceae, or palm family. They are used in commercial agriculture in the production of palm oil. The African Oil Palm Elaeis guineensis is native to west Africa, occurring between Angola and Gambia, while the American Oil Palm Elaeis oleifera is native to tropical Central America and South America. Mature trees are single-stemmed, and grow to 20 m tall. The leaves are pinnate, and reach between 3-5 m long. A young tree produces about 30 leaves a year. Established trees over 10 years produce about 20 leaves a year. The flowers are produced in dense clustes; each individual flower is small, with three sepals and three petals. The fruit takes six months to mature from pollination to maturity; it comprises an oily, fleshy outer layer (the pericarp), with a single seed (kernel), also rich in oil. Unlike its relative, the Coconut Palm, the oil palm does not produce offshoots; propagation is by sowing the seeds.

Agriculture

Oil palms are grown for their clusters of fruit, which can weigh 40-50 kg. Upon harvest, the drupe, pericarp and seeds are used for production of soap and edible vegetable oil; different grades of oil quality are obtained from the pericarp and the kernel, with the pericarp oil used mainly for cooking oil, and the kernel oil used in processed foods. For each hectare of oil palm, which is harvested year-round, the annual production averages 10 tonnes of fruit, which yields 3,000 kg of pericarp oil, and 750 kg of seed kernels, which yield 250 kg of high quality palm kernel oil as well as 500 kg of kernel meal. The meal is used to feed livestock. Some varieties have even higher productivities which has led to their consideration for producing the vegetable oil needed for biodiesel. The African Oil Palm was introduced to Sumatra and the Malaya area in the early 1900s; many of the largest plantations of oil palms are now in this area, with Malaysia growing over 20,000 square kilometres. Malaysia claims that in 1995 it was the world's largest producer with 51% of world production. In this area, the destruction of natural rainforest to grow oil palm plantations is an issue of major environmental concern.

Nutrition

Palm oil is high in vitamin K and dietary Magnesium. Palm oil contains 43 percent saturated fats, 43 percent monounsaturated fats and 13 percent polyunsaturated fats. Its high nutritional value means that the palm nut is eaten by a wide variety of animals, including, rather improbably, two birds of prey, the Palm Nut Vulture and the Harrier Hawk.

External links

- [http://www.mpopc.org.my/index1.htm Malaysian Palm Oil Promotion Council (MPOPC)]
- [http://www.journeytoforever.org/biodiesel_yield.html Biodiesel production]
- [http://www.foe.co.uk/campaigns/biodiversity/case_studies/palm_oil/index.html Friends of the Earth UK: Palm oil - rainforest in your shopping]
- [http://www.cspinet.org/palmoilreport/index.html Center for Science in the Public Interest: Cruel Oil - How Palm Oil Harms Health, Rainforest and Wildlife] Category:Palms ja:アブラヤシ

Arecaceae

Many; see list of Arecaceae genera Arecaceae (also known as Palmae), the Palm Family, is a family of flowering plants, belonging to the monocot order, Arecales. There are 202 currently known genera with around 2,600 species, most of which are restricted to tropical or subtropical climates. Of all the families of plants, the Arecaceae is the most easily recognizable as distinct by most persons. The type member of this family is the areca palm, the fruit of which is chewed with the betel leaf and often confused with it. The Date Palm, Rattan, and Coconut also belong to this family. Palm oil is an edible vegetable oil produced by the oil palms in the genus Elaeis. Several species are harvested for heart of palm. Palm sap is sometimes fermented to produce palm wine. The Palm Sunday festival uses palms, hence the name. Palms first appear in the fossil record around 70-80 million years ago, during the Cretaceous Period, making them one of the older families of flowering plants. Economically important genera include:
- Areca
- Arenga
- Attalea
- Bactris
- Borassus (Palmyra Palm)
- Calamus - rattan palm
- Cocos - coconut
- Copernicia - carnauba wax palm
- Elaeis - oil palm
- Euterpe Cabbage Heart Palm, and Açaí Palm
- Jessenia
- Jubaea Chilean Wine Palm and Coquito Palm
- Orbignya
- Phoenix - date palms
- Rhapis
- Roystonea - royal palm
- Sabal - palmetto
- Salacca - salak
- Trachycarpus
- Veitchia
- Wallichia
- Washingtonia See list of Arecaceae genera for a complete listing. list of Arecaceae genera list of Arecaceae genera Few palms tolerate severe cold, and the majority of the species are tropical or subtropical. The most cold-tolerant are Trachycarpus, native to eastern Asia, and Rhapidophyllum, native to the southeastern United States. For more details, see hardy palms. In the United States, different types of palm trees can be seen in tropical and mediterranean climate areas, such as Florida, (southern) California and Hawaii and along the Gulf Coast through southern Georgia, Mississippi, Alabama, and Louisiana to Texas. The southeastern state of South Carolina is nicknamed the Palmetto State because of the number of palms that line the state's Atlantic coast. Some palms can be grown as far north as Maryland, Arkansas, and even up along the Pacific coast to Oregon and Washington. There have even been known species of transplanted palms that have survived as far north as southern New Jersey [http://www.bg-map.com/palms/woodbury.html]. The desert areas of Nevada, Arizona, Utah and New Mexico are also home to some native palms. Southern Europe has two native palms, Chamaerops humilis (widespread, but mainly seen in Portugal, Spain, France, Italy and Malta) and Phoenix theophrastii (Crete; also southern Turkey). Many other palms are widely planted, with the Japanese Trachycarpus wagnerianus being grown successfully as far north as Iceland.

References

- C. H. Schultz-Schultzenstein (1832). Natürliches System des Pflanzenreichs..., 317. Berlin, Germany.
- N. W. Uhl, J. Dransfield (1987). Genera palmarum: a classification of palms based on the work of Harold E. Moore, Jr. (Allen Press, Lawrence, Kansas)

External links

- [http://www.kew.org/cgi-bin/web.dbs/genlist.pl?PALMAE Kew Botanic Garden's Palm Genera list] A list of the currently acknowledged genera by Kew Royal Botanic Gardens in London, England.
- [http://www.plantapalm.com/vpe/taxonomy/vpe_taxonomy3.htm Taxonomy of the family Arecaceae]
- [http://www.pacsoa.org.au/palms/ PACSOA] Palm and Cycad Societies of Australia palm species listing with images.
- [http://www.plantapalm.com/vpe/photos/vpe_photos.htm Plant a Palm] A website with a large amount of information on palms, their cultivation and uses. This link goes to the photo gallery via species listing. Category:Plant families Category:Palms ja:ヤシ (植物) th:ปาล์ม

Palm oil

Palm oil is a form of edible vegetable oil obtained from the fruit of the Oil palm tree. The oil palm is a tropical palm tree. There are two species of oil palm, the better known one is the one originating from Guinea, Africa and was first illustrated by Nicholaas Jacquin in 1763, hence its name, Elaeis guineensis Jacq. Nicholaas Jacquin The fruit is reddish, about the size of a large plum and grows in large bunches. A bunch of fruits can weigh between 10 to 40 kilograms each. Each fruit contains a single seed (the palm kernel) surrounded by a soft oily pulp. Oil is extracted from both the pulp of the fruit (palm oil, an edible oil) and the kernel (palm kernel oil, used mainly for soap manufacture). For every 100 kilograms of fruit bunches, you typically extract 22 kilograms of palm oil and 1.6 kilograms of palm kernel oil. Palm oil itself is reddish and contains a high amount of carotenoids. It is used as cooking oil, to make margarine and is a component of many processed foods. Both palm oil and palm kernel oil are high in olefins, a potentially valuable chemical group that can be processed into many non-food products as well. Palm oil contains mainly palmitic and oleic acids, while palm kernel oil contains mainly lauric acid. Palm oil is the largest natural source of tocotrienol, part of the Vitamin E family. Palm oil is one of the few vegetable oils relatively high in saturated fats, though it is not as high in them as palm kernel oil. The high productivity of the Oil palm at producing oil (as high as 7,250 liters per hectare per year) has made it the prime source of vegetable oil for many tropical countries. It is also likely to be used for producing the necessary vegetable oil for biodiesel, an example being a planned refinery Darwin, Australia which will import the palm oil from Indonesia and Malaysia. The Oil palm originated in West Africa but has since been planted successfully in tropical regions within 20 degrees of the equator. In the Republic of the Congo, or Congo Brazzaville, precisely in the Northern part, not far from Ouesso, local people produce this oil by hand. They harvest the fruit, boil it to let the water part evaporate, then they press what its left in order to collect the reddish, orange colored oil. The world's largest producer and exporter of palm oil today is Malaysia, producing about 47% of the world's supply of palm oil. Indonesia is the second largest world producer of palm oil producing approximately 36% of world palm oil volume. Both nations are expanding their palm oil production capacity and the market continues to grow. There is evidence of palm oil use in Ancient Egypt.

Environmental and cultural impact

There is increasing concern from environmental and other NGOs about the environmental impacts of the palm oil industry. It is claimed that rainforests are being cleared to make room for the plantations, thus reducing the habitat for some threatened species, such as the orangutan (on Borneo and Sumatra). The resulting plantations are often run by agribusiness, and locals in places such as West Papua are missing out on jobs in them to migrant workers.

External links

- [http://www.mpob.gov.my Malaysian palm oil board]
- [http://www.sustainable-palmoil.org/ Roundtable on Sustainable Palm Oil]
- [http://www.mpopc.org.my/ Malaysian Palm Oil Promotion Council]
- [http://www.tis-gdv.de/tis_e/ware/oele/palmoel/palmoel.htm Physical properties of palm oil]
- [http://www.fedepalma.org/oil_palm.htm Another website on oil palm]
- [http://www.oilpalmworld.com/ Oilpalmworld - The first comprehensive palm oil e-Marketplace] Category:Cooking oils ms:Sawit

Angola

Angola is a country in southwestern Africa bordering Namibia, the Democratic Republic of the Congo, and Zambia, and with a west coast along the Atlantic Ocean. The exclave province Cabinda has a border with Congo-Brazzaville. A former Portuguese colony, it has considerable natural resources, among which oil and diamonds are the most relevant. The country is nominally a democracy and is formally named the Republic of Angola (Portuguese: República de Angola).

Origin and history of the name

The name Angola is a Portuguese derivation of the Bantu word N’gola, being the title of the native rulers of the Quimbundos Kingdom in the 16th century, at the time of colonization by the Portuguese.

History

Main article: History of Angola History of Angola In present-day Angola Portugal settled in 1483 at the river Congo, where the Kongo State, Ndongo and Lunda existed. The Kongo State stretched from modern Gabon in the north to the Kwanza River in the south. Portugal established in 1575 a Portuguese colony at Luanda based on the slave trade. The Portuguese gradually took control of the coastal strip throughout the 16th century by a series of treaties and wars. They formed the colony of Angola. The Dutch occupied Luanda from 1641-48, providing a boost for anti-Portuguese states. In 1648 Portugal retook Luanda and initiated a process of military conquest of the Kongo and Ndongo states that ended with Portuguese victory in 1671. Full Portuguese administrative control of the interior didn't occur until the beginning of the 20th century. In 1951 the colony was restyled as an overseas province, also called Portuguese West Africa. When Portugal refused a decolonization process three independence movements emerged:
- the Popular Movement for the Liberation of Angola (Movimento Popular de Libertação de Angola MPLA), with a base among Kimbundu and the mixed-race intelligentsia of Luanda, and links to communist parties in Portugal and the Eastern Bloc;
- the National Liberation Front of Angola (Frente Nacional de Libertação de Angola, FNLA), with an ethnic base in the Bakongo region of the north and links to the United States and the Mobutu regime in Zaire; and
- the National Union for Total Independence of Angola (União Nacional para a Independência Total de Angola, UNITA), led by Jonas Malheiro Savimbi with an ethnic and regional base in the Ovimbundu heartland in the center of the country. After a 14 year independence guerrilla war, and the overthrow of fascist Portugal's government by a military coup, Angola's nationalist parties began to negotiate for independence in January 1975. Independence was to be declared in November 1975. Almost immediately, a civil war broke out between MPLA, UNITA and FNLA, exacerbated by foreign intervention. South African troops struck an alliance of convenience with UNITA and invaded Angola in August 1975 to ensure that there would be no interference (by a newly independent Angolan state) in Namibia, which was then under South African control (Hodges, 2001, 11). Cuban troops came to the support of the MPLA in October 1975, enabling them to hold off the South African forces and declare themselves as the de facto government of the country when independence was formally declared in November. In 1976, the FNLA was defeated by a combination of MPLA and Cuban troops, leaving the Marxist MPLA and UNITA (backed by the United States and South Africa) to fight for power. The conflict raged on, fuelled by the geopolitics of the Cold War and by the ability of both parties to access resources from Angola's natural resources. The MPLA drew upon the revenues of off-shore oil reserves, while UNITA accessed alluvial diamonds that were easily smuggled through the region's very porous borders (LeBillon, 1999). In 1991, the factions agreed to turn Angola into a multiparty state, but after the current president José Eduardo dos Santos of MPLA won UN supervised elections, UNITA claimed there was fraud and fighting broke out again. A 1994 peace accord (Lusaka protocol) between the government and UNITA provided for the integration of former UNITA insurgents into the government. A national unity government was installed in 1997, but serious fighting resumed in late 1998, rendering hundreds of thousands of people homeless. President José Eduardo dos Santos suspended the regular functioning of democratic instances due to the conflict. On February 22nd 2002, Jonas Savimbi, the leader of UNITA, was shot dead and a cease-fire was reached by the two factions. UNITA gave up its armed wing and assumed the role of major opposition party. Although the political situation of the country seems to be normalizing, president dos Santos still hasn't allowed regular democratic processes to take place. Among Angola's major problems are a serious humanitarian crisis (a result of the prolonged war), the abundance of mine fields, and the actions of guerrilla movements fighting for the independence of the northern enclave of Cabinda (Frente para a Libertação do Enclave de Cabinda). Angola, like many sub-Saharan nations, is subject to periodic outbreaks of infectious diseases. As of early April 2005, Angola is in the midst of an outbreak of the Marburg virus which is rapidly becoming the worst outbreak of a hemmorhagic fever in recorded history, with over 237 deaths recorded out of 261 reported cases, and having spread to 7 out of the 18 provinces as of April 19, 2005.

Politics

Main article: Politics of Angola The executive branch of the government is composed of the President, the Prime Minister (currently Fernando da Piedade Dias dos Santos) and Council of Ministers. Currently, political power is concentrated in the Presidency. The Council of Ministers, composed of all government ministers and vice ministers, meets regularly to discuss policy issues. Governors of the 18 provinces are appointed by and serve at the pleasure of the president. The Constitutional Law of 1992 establishes the broad outlines of government structure and delineates the rights and duties of citizens. The legal system is based on Portuguese and customary law but is weak and fragmented, and courts operate in only 12 of more than 140 municipalities. A Supreme Court serves as the appellate tribunal; a Constitutional Court with powers of judicial review has never been constituted despite statutory authorization. The 27 year long civil war has ravaged the country's political and social institutions. The UN estimates of 1.8 million internally displaced persons (IDPs), while generally the accepted figure for war-affected people is 4 million. Daily conditions of life throughout the country and specifically Luanda (population approximately 4 million) mirror the collapse of administrative infrastructure as well as many social institutions. The ongoing grave economic situation largely prevents any government support for social institutions. Hospitals are without medicines or basic equipment, schools are without books, and public employees often lack the basic supplies for their day-to-day work. The president has announced the government's intention to hold elections in 2006. These elections would be the first since 1992 and would serve to elect both a new president and a new National Assembly.
- List of political parties in Angola

Administrative Divisions

List of political parties in Angola Main Article: Provinces of Angola Angola is divided into 18 provinces:-

Geography

Provinces of Angola Provinces of Angola Main article: Geography of Angola Angola is bordered by Namibia to the south, Zambia to the east, the Democratic Republic of the Congo to the north-east, and the South Atlantic Ocean to the west. The exclave of Cabinda also borders the Republic of the Congo to the north. Angola's capital, Luanda, lies on the Atlantic coast in the north-west of the country. Angola is divided into an arid coastal strip stretching from Namibia to Luanda; a wet, interior highland; a dry savanna in the interior south and southeast; and rain forest in the north and in Cabinda. The Zambezi River and several tributaries of the Congo River have their sources in Angola.

Exclaves and enclaves

The exclave province of Cabinda borders with both the Republic of the Congo and the Democratic Republic of the Congo. The latter's only oceanic access, 60 km in width, divides Angola from Cabinda. The population stands at around 300,000, two-thirds of which inhabit the surroundings in a generally stable state on Congolese and Zairian territory. The Angolan central government has yet to put a definitive end to the Cabindese secessionist movement.

Economy

Main article: Economy of Angola Angola is an economy in disarray because of a quarter century of nearly continuous warfare. Despite its abundant natural resources, output per capita is among the world's lowest. Subsistence agriculture provides the main livelihood for 85% of the population. Oil production and the supporting activities are vital to the economy, contributing about 45% to GDP and 90% of exports. Control of the oil industry is consolidated in Sonangol Group, a conglomerate which is owned by the Angolan government. Notwithstanding the signing of a peace accord in November 1994, violence continues, millions of land mines remain, and many farmers are reluctant to return to their fields. As a result, much of the country's food must still be imported. Despite the increase in the pace of civil warfare in late 1998, the economy grew by an estimated 4% in 1999. The government introduced new currency denominations in 1999, including a 1 and 5 kwanza note. Expanded oil production brightens prospects for 2000, but internal strife discourages investment outside of the petroleum sector. With the advent of peace in 2002 a strategic partnership with China is set in motion, so huge investments by Chinese companies are now in place, especially in the construction sector and more recently in the metallurgical sector.

Demographics

Main article: Demographics of Angola Angola has three main ethnic groups, each speaking a Bantu language: Ovimbundu 37%, Kimbundu 25%, and Bakongo 13%. Other groups include Chokwe (or Lunda), Ganguela, Nhaneca-Humbe, Ambo, Herero, and Xindunga. In addition, mestiços (Angolans of mixed European and African family origins) amount to about 2%, with a small (1%) population of whites, mainly ethnically Portuguese. Portuguese make up the largest non-Angolan population, with at least 30,000 (though many native-born Angolans can claim Portuguese nationality under Portuguese law). Portuguese is both the official and predominant language, spoken in the homes of about two-thirds of the population, and as a secondary language by many more. The great majority of the inhabitants are of Bantu stock with some admixture in the Congo district. In the south-east are various tribes of Bushmen. The best-known of the Bantu tribes are the Ba-Kongo (Ba-Fiot), who dwell chiefly in the north, and the Abunda (Mbunda, Ba-Bundo), who occupy the central part of the province, which takes its name from the Ngola tribe of Abunda. Another of these tribes, the Bangala, living on the west bank of the upper Kwango, must not be confused with the Bangala of the middle Congo. In the Abunda is a considerable strain of Portuguese blood. The Ba-Lunda inhabit the Lunda district. Along the upper Kunene and in other districts of the plateau are settlements of Boers, the Boer population being about 2000. In the coast towns the majority of the white inhabitants are Portuguese. The Mushi-Kongo and other divisions of the Ba-Kongo retain curious traces of the Christianity professed by them in the 16th and 17th centuries and possibly later. Crucifixes are used as potent fetish charms or as symbols of power passing down from chief to chief; whilst every native has a "Santu" or Christian name and is dubbed dom or dona. Fetishism is the prevailing religion throughout the province. The dwelling-places of the natives are usually small huts of the simplest construction, used chiefly as sleeping apartments; the day is spent in an open space in front of the hut protected from the sun by a roof of palm or other leaves. Despite all that, Catholicism remains the dominant religion, although recently an increasing number of churches are claiming more followers, particularly evangelicals.
- List of Angolans

Culture

Main article: Culture of Angola
- List of writers from Angola
- Contemporary Dance Company of Angola[http://www.cdcangola.com]

Stamps

- List of errors on Portuguese ex-Colonies stamps of Angola 1912
- List of errors on Portuguese ex-Colonies stamps of Angola 1914
- List of errors on Portuguese ex-Colonies stamps of Angola 1921
- List of birds on stamps of Angola
- List of people on stamps of Angola
- List of bonsai on stamps
- List of fish on stamps

Miscellaneous topics

- Communications in Angola
- Foreign relations of Angola
- List of Angolan companies
- Military of Angola
- Sonangol Group
- Transportation in Angola

Reference

- Much of the material in these articles comes from the CIA World Factbook 2000 and the 2003 U.S. Department of State website.

External links

Government

- [http://www.angola.org/ Republic of Angola] official government portal
- [http://www.parlamento.ao/ National Assembly of Angola] official site (in Portuguese)
- [http://www.angola.org/ Embassy of Angola in Washington DC] government information and links

News

- [http://allafrica.com/angola/ allAfrica - Angola] news headline links
- [http://www.angolapress-angop.ao/ Angola Press] government-controlled news agency (in Portuguese, French and English)
- [http://www.angonoticias.com/ Angonoticias] (in Portuguese) - A popular news source in Angola

Overviews

- [http://news.bbc.co.uk/1/hi/world/africa/country_profiles/1063073.stm BBC - Country profile: Angola]
- [http://www.cia.gov/cia/publications/factbook/geos/ao.html CIA World Factbook - Angola]
- [http://www.state.gov/p/af/ci/ao/ US State Department - Angola] includes Background Notes, Country Study and major reports

Directories

- [http://www.columbia.edu/cu/lweb/indiv/africa/cuvl/Angola.html Columbia University Libraries - Angola] directory category of the WWW-VL
- [http://dmoz.org/Regional/Africa/Angola/ Open Directory Project - Angola] directory category
- [http://www-sul.stanford.edu/depts/ssrg/africa/angola.html Stanford University - Africa South of the Sahara: Angola] directory category
- [http://dir.yahoo.com/Regional/Countries/Angola/ Yahoo! - Angola] directory category

Tourism

Other

- [http://www.flashpoints.info/countries-conflicts/Angola-web/angola_briefing.html Angola Conflict Briefing] Category:African Union member states Category:Former Portuguese colonies Category:CPLP member states zh-min-nan:Angola ko:앙골라 ms:Angola ja:アンゴラ simple:Angola

Gambia

The Republic of The Gambia is a country in West Africa. It is the smallest country within the African continent and is entirely surrounded by Senegal, with the Gambia River emptying into the Atlantic Ocean in its center. In 1965, The Gambia became independent from the British Empire. Banjul is its capital.

History

Main article: History of the Gambia Gambia was once part of the Empire of Ghana and the Songhai Empire. The first written accounts of the region come from records of Arab traders in the 9th and 10th centuries A.D. Arab traders established the trans-Saharan trade route for slaves, gold, and ivory. In the 15th century, the Portuguese took over this trade using maritime routes. At that time, The Gambia was part of the Mali Empire. In 1588, the claimant to the Portuguese throne, Antonio, Prior of Crato, sold exclusive trade rights on the Gambia River to English merchants; this grant was confirmed by letters patent from Queen Elizabeth I. In 1618, King James I granted a charter to a British company for trade with The Gambia and the Gold Coast (now Ghana). Between 1651 and 1661 Gambia was (indirectly) a colony of Polish-Lithuanian Commonwealth; it was purchased by the Courlandish prince Jakub Kettler. At that time Courland was a fiefdom of the Polish-Lithuanian Commonwealth. Courland During the late 17th century and throughout the 18th, England and France struggled continuously for political and commercial supremacy in the regions of the Senegal and Gambia Rivers. The 1783 Treaty of Versailles gave Great Britain possession of The Gambia, but the French retained a tiny enclave at Albreda on the north bank of the river that was ceded to the United Kingdom in 1857. American author Alex Haley (Roots) traced his ancestry to the Mandinka tribe in the Gambia River village of Juffure, during the 1760s. As many as 3 million slaves may have been taken from the region during the three centuries that the transatlantic slave trade operated. In 1807, slave trading was abolished throughout the British Empire, and the British tried unsuccessfully to end the slave traffic in The Gambia. They established the military post of Bathurst (now Banjul) in 1816. In the ensuing years, Banjul was at times under the jurisdiction of the British governor general in Sierra Leone. In 1888, The Gambia became a separate colonial entity. In 1889, it became a crown colony. Roots After World War II, the pace of constitutional reform quickened. Following general elections in 1962, full internal self-government was granted in 1963. The Gambia achieved independence on February 18, 1965, as a constitutional monarchy within the British Commonwealth. On April 24, 1970, The Gambia became a republic following a referendum. Until a military coup in July 1994, The Gambia was led by President Sir Dawda Kairaba Jawara, who was re-elected five times. The relative stability of the Jawara era was first broken by a violent, unsuccessful coup attempt in 1981. In the aftermath of the attempted coup, Senegal and The Gambia signed the 1982 Treaty of Confederation. The result, the Senegambia Confederation, aimed eventually to combine the armed forces of the two nations and to unify economies and currencies. The Gambia withdrew from the confederation in 1989. 1989 In July 1994, the Armed Forces Provisional Ruling Council (AFPRC) seized power in a military coup d'etat, deposing the government of Sir Dawda Jawara. Lieutenant Yahya A.J.J. Jammeh, chairman of the AFPRC, became head of state. The AFPRC announced a transition plan for return to democratic civilian government. The Provisional Independent Electoral Commission (PIEC) was established in 1996 to conduct national elections. The PIEC was transformed to the Independent Electoral Commission (IEC) in 1997 and became responsible for registration of voters and conduct of elections and referenda. In late 2001 and early 2002, The Gambia completed a full cycle of presidential, legislative, and local elections, which foreign observers deemed free, fair, and transparent, albeit with some shortcomings. President Yahya Jammeh, who was re-elected, took the oath of office again on December 21, 2001. The APRC maintained its strong majority in the National Assembly, particularly after the main opposition United Democratic Party (UDP) boycotted the legislative elections.

Politics

Yahya A.J.J. Jammeh Main article: Politics of the Gambia Before the coup d'état in July 1994, The Gambia was one of the oldest existing multi-party democracies in Africa. It had conducted freely contested elections every 5 years since independence. After the military coup, politicians from deposed President Jawara's People's Progressive Party (PPP) and other senior government officials were banned from participating in politics until July 2001. Following the coup in July 1994, a presidential election took place in September 1996, in which retired Col. Yahya A.J.J. Jammeh won 56% of the vote. Four registered opposition parties participated in the October 18, 2001, presidential election, which the incumbent, President Jammeh, won with almost 53% of the votes. The APRC maintained its strong majority in the National Assembly in legislative elections held in January 2002, particularly after the main opposition United Democratic Party (UDP) boycotted the legislative elections.

Government

The 1970 constitution, which divided the government into independent executive, legislative, and judicial branches, was suspended after the 1994 military coup. As part of the transition process, the AFPRC established the Constitution Review Commission (CRC) through decree in March 1995. In accordance with the timetable for the transition to a democratically elected government, the commission drafted a new constitution for The Gambia, which approved by referendum in August 1996. The constitution provides for a strong presidential government, a unicameral legislature, an independent judiciary, and the protection of human rights. See also: Heads of State of the Gambia, Foreign Relations of the Gambia, Military of the Gambia

Subdivisions

Military of the Gambia Main article: Subdivisions of The Gambia The Gambia is divided into five divisions and one city:
- Lower River
- Central River
- North Bank
- Upper River
- Western The national capital, Banjul, is classified as a city.

Geography

Banjul Banjul Banjul Banjul Banjul Banjul Banjul Banjul Banjul Main article: Geography of the Gambia The Gambia is a very small and narrow country with the border based on the Gambia River. The country is less than 48km wide, with a total area of 11,300 km². Its present boundaries were defined in 1889 after an agreement between the United Kingdom and France. It is almost an enclave of Senegal and the smallest country on the continent of Africa.

Economy

Main article: Economy of the Gambia The Gambia has a liberal, market-based economy characterized by traditional subsistence agriculture, a historic reliance on groundnuts (peanuts) for export earnings, a re-export trade built up around its ocean port, low import duties, minimal administrative procedures, a fluctuating exchange rate with no exchange controls, and a significant tourism industry. Agriculture accounts for 29% of gross domestic product (GDP) and employs 75% of the labor force. Within agriculture, peanut production accounts for 6.9% of GDP, other crops 8.3%, livestock 5.3%, fishing 1.8%, and forestry 0.5%. Industry accounts for 12% of GDP. Manufacturing accounts for 5.5% of GDP. The limited amount of manufacturing is primarily agriculturally based (e.g., peanut processing, bakeries, a brewery, and a tannery). Other manufacturing activities include soap, soft drinks, and clothing. Services account for 19% of GDP. The U.K. and other EU countries constitute The Gambia's major domestic export markets, accounting for 86% in total; followed by Asia at 14%; and the African subregion, including Senegal, Guinea-Bissau, and Ghana at 8%. The U.K. and the other EU countries--namely, Germany, France, Netherlands, and Belgium--were the major source of imports accounting for 60% of the total share of imports followed by Asia at 23%, and Cote d'Ivoire and other African countries at 17%. The Gambia reports 11% of its exports going to and 14.6% of its imports coming from the United States.

Demographics

Main article: Demographics of the Gambia A wide variety of ethnic groups live in The Gambia with a minimum of intertribal friction, each preserving its own language and traditions. The Mandinka tribe is the largest, followed by the Fula, Wolof, Jola, and Serahule. Approximately 3,500 non-Africans live in The Gambia, including Europeans and families of Lebanese origin. Muslims constitute more than 95% of the population. Christians of different denominations account for most of the remainder. Gambians officially observe the holidays of both religions and practice religious tolerance. More than 63% of Gambians live in rural villages (1993 census), although more and more young people come to the capital in search of work and education. Provisional figures from the 2003 census show that the gap between the urban and rural populations is narrowing as more areas are declared urban. While urban migration, development projects, and modernization are bringing more Gambians into contact with Western habits and values, the traditional emphasis on the extended family, as well as indigenous forms of dress and celebration, remain integral parts of everyday life.

Culture

Main article: Culture of the Gambia See also: Music of the Gambia

Miscellaneous topics

- Communications of the Gambia
- Birds of the Gambia
- List of Gambian companies
- Public holidays in the Gambia
- Transportation of the Gambia

References

- Much of the information presented here comes from the CIA World Factbook 2000 and the 2002 U.S. Department of State website.

External links

Government
- [http://www.suha.consul.cc/ Consulate of Gambia in Hungary]
- [http://www.nationalassembly.gm/ National Assembly of The Gambia] official site
- [http://www.gambia.gm/ Republic of The Gambia - Department of State for Trade, Industry and Employment (DOSTIE)] official site News
- [http://allafrica.com/gambia/ allAfrica.com - Gambia] news headline links Overviews
- [http://news.bbc.co.uk/1/hi/world/africa/country_profiles/1032156.stm BBC News Country Profile - The Gambia]
- [http://www.cia.gov/cia/publications/factbook/geos/ga.html CIA World Factbook - The Gambia] Directories
- [http://gambiagateway.atspace.com/ Gambia Gateway websites] directory category
- [http://dmoz.org/Regional/Africa/Gambia/ Open Directory Project - Gambia] directory category
- [http://www-sul.stanford.edu/depts/ssrg/africa/gambia.html Stanford University - Africa South of the Sahara: Gambia] directory category
- [http://www.afrika.no/index/Countries/Gambia/ The Index on Africa - Gambia] directory category
- [http://www.sas.upenn.edu/African_Studies/Country_Specific/Gambia.html University of Pennsylvania - African Studies Center: Gambia] directory category
- [http://dir.yahoo.com/Regional/Countries/Gambia__The/ Yahoo! - The Gambia] directory category Tourism Music
- [http://www.coraconnection.com/ Cora Connection] West African music resources Other
- [http://www.erslah.com/attaya/ Friends of Senegal and The Gambia] (Returned Peace Corps Volunteer site)
- [http://gambiagateway.atspace.com/information/index.html Gambia Information] Gambia Gambia
- zh-min-nan:Gambia ko:감비아 ms:Gambia ja:ガンビア

Central America

Commonly, Central America is the region of North America located between the southern border of Mexico and the northwest border of Colombia, in South America. Some geographers classify Central America as a large isthmus, and in this geographic sense it sometimes includes the portion of Mexico east of the Isthmus of Tehuantepec, namely the Mexican states of Chiapas, Tabasco, Campeche, Yucatán and Quintana Roo. However, Central America is much more commonly understood to correspond with the nations between Mexico and Colombia. The UN subregion of Central America includes all mainland states of North America south of the US, including Mexico. US

Countries

In one common definition, Central America consists of the following countries (located between the the northwest border of Colombia and the southern border of Mexico—roughly east to west):
- Panama
- Costa Rica
- Nicaragua
- Honduras
- El Salvador
- Guatemala
- Belize

Geography

Central America thus has an area of about 540,000 km² (208,500 mi²), and a width between the Pacific Ocean and the Caribbean Sea ranging from about 560 km to about 50 km (350 to 30 mi). Caribbean Sea.]] The geology of Central America is active, with volcanic eruptions and earthquakes occurring from time to time. In 1931 and 1972 earthquakes devastated Managua, the capital of Nicaragua. Fertile soils from weathered volcanic lavas have made it possible to sustain dense populations in the agriculturally productive highland areas. The Caribbean Plate is a tectonic plate upon which Central America rests. The narrowest part of The Americas, Central America is the site of the Panama Canal as well as the proposed, but never-completed Nicaragua Canal.

History

There was a nation of Central America in the early 19th century, consisting of the present day nations of Guatemala, Honduras, El Salvador, Nicaragua, and Costa Rica (and a portion of the modern Mexican state of Chiapas). This was sometimes known as the United Provinces of Central America or the United States of Central America.

External links

- [http://www.fssca.net/ Foundation for Self-Sufficiency in Central America] Category:Americas Category:North America zh-min-nan:Tiong Bí-chiu ko:중앙아메리카 ja:中央アメリカ simple:Central America

South America

South America is a continent, with most of its area in the Southern Hemisphere. South America is situated between the Pacific Ocean and the Atlantic Ocean. Commonly referred to as part of America, like North America, South America is named after Amerigo Vespucci, who was the first European to suggest that the Americas were not the East Indies, but a previously undiscovered New World. South America has an area of 17,821,601 km² (6,880,959 sq mi), or almost 3.5% of the Earth's surface. As of 2005, its population was estimated at more than 371,200,000. South America ranks fourth in area (after Asia, Africa, and North America) and fifth in population (after Asia, Africa, Europe, and North America).Europe __TOC__

Geography

The classification of its geographic location is subject to dispute, as in some non-English speaking regions of the world, the Americas are a continent and North, Central and South America are its subcontinents. In English-speaking and certain other regions of the world, North and South America are considered to be continents and their union is referred to as the supercontinent of the Americas. The classification given to South America, as a subcontinent in a continent or a continent in a supercontinent, depends entirely on regional preferences. It became attached to North America only recently (geologically speaking) with the formation of the Isthmus of Panama some 3 million years ago, which resulted in the Great American Interchange. The Andes, likewise a comparatively young and seismically restless mountain range, run down the western edge of the continent; the land to the east of the Andes is largely tropical rain forest, the vast Amazon River basin. The continent also contains drier regions such as Patagonia and the extremely arid Atacama desert. The region of South America also includes various islands, most of which belong to countries on the continent. The Caribbean territories are grouped with North America. The South American nations that border the Caribbean Sea – including Colombia, Venezuela, Guyana, Suriname, and French Guiana – are also known as Caribbean South America. Major natural resources are copper, iron ore, tin and oil. The many resources in South America have become useful around the world, but they have failed to diversify their economies. This has lead to major highs and lows in their economy causing instability. South America is home to many interesting species of animals including parrots, tarantulas, snakes, and mammals. The largest country in South America by far, in both area and population, is Brazil followed by Argentina. Regions in South America include the Andean States, the Guianas, the Southern Cone, and Eastern South America.

History

South America is thought to have been first inhabited by people crossing the Bering Land Bridge, now the Bering strait, though there are also suggestions of migration from the southern Pacific Ocean.

Chavín

The Chavín established a trade network and developed agriculture by 900 BC, according to some estimates and archeological finds. Artifacts were found at a site called Chavín de Huantar in modern Peru at an elevation of 3,177 meters. Chavín civilization spanned 900 BC to 300 BC.

Inca

Holding their capital at the great city of Cusco, the Inca civilization dominated the Andes region from 1438 to 1533. Known as Tahuantinsuyu, or "the land of the four regions," in Quechua, the Inca culture was highly distinct and developed. Cities were built with precise, unmatched stonework, constructed over many levels of mountain terrain. Terrace farming was a useful form of agriculture. There is evidence of excellent metalwork and even successful brain surgery in Inca civilization.

European colonization

Before arrival of Europeans, an estimated 30 million people lived in South America. brain surgery In 1494, Portugal and Spain, the two great maritime powers of that time, on the expectation of new lands being discovered in the west, signed the Treaty of Tordesillas, by which they agreed that all the land outside Europe should be an exclusive duopoly between the two countries. The Treaty established an imaginary line along a north-south meridian 370 leagues west of Cape Verde Islands, roughly 46° 37' W. In terms of the treaty, all land to the west of the line (which is now known to comprehend most of the South American soil), would belong to Spain, and all land to the east, to Portugal. As accurate measurements of longitude were impossible at that time, the line was not strictly enforced, resulting in a Portuguese expansion of Brazil across the meridian. Beginning in the 1530s, the people and natural resources of South America were repeatedly exploited by foreign conquistadors, first from Spain and later from Portugal. These competing colonial nations claimed the land and resources as their own and divided it into colonies. European diseases (smallpox, influenza, measles and typhus) to which the native populations had no resistance, and cruel systems of forced labor, such as the infamous haciendas and mining industry's mita, decimated the American population under Spanish control. After this, African slaves, who had developed immunities to these diseases, were quickly brought in to replace them. The Spaniards were committed to converting their American subjects to Christianity, and were quick to purge any native cultural practices that hindered this end. However, most initial attempts at this were only partially successful, as American groups simply blended Catholicism with their traditional beliefs. On the other hand, the Spaniards did not impose their language to the degree they did their religion, and the Catholic Church's evangelization in , and actually contributed to the expansion of these American languages, equipping them with writing systems. Eventually the Natives and the Spaniards interbred, forming a Mestizo class. These and the original Americans were often forced to pay unfair taxes to the Spanish government and were punished harshly for disobeying their laws. Many native artworks were considered pagan idols and destroyed by Spanish explorers. This included the many gold and silver sculptures found in the Americas, which were melted down before transport to Europe. Mestizo

Independence

The Spanish colonies won their independence in the first quarter of the 19th century, in the South American Wars of Independence. Simon Bolivar and José de San Martín led their independence struggle. In Brazil, a Portuguese colony, Dom Pedro I (also Pedro IV of Portugal), son of the Portuguese king Dom João VI, proclaimed the country's independence in 1822 and became Brazil's first Emperor. This was peacefully accepted by the crown in Portugal. Although Bolivar attempted to keep the Spanish-speaking parts of the continent politically unified, they rapidly became independent of one another as well, and several further wars were fought, such as the War of the Triple Alliance and the War of the Pacific. A few countries did not gain independence until the 20th century:
- Trinidad and Tobago, from the United Kingdom, in 1962
- Guyana, from the United Kingdom, in 1966.
- Suriname, from the Dutch control, in 1975 French Guiana remains part of France as of 2005, and hosts the European Union's principal spaceport, the Centre Spatial Guyanais.

Recent history

The continent, like many others, became a battlefield of the Cold War in the late 20th century. The government of Chile was overthrown in the early 1970s, as a late (and peculiar) development of the U.S. Monroe Doctrine. Throughout the 1980s and 1990s, Peru suffered from internal conflicts (see Túpac Amaru Revolutionary Movement and Shining Path). Other revolutions and military dictatorships have been common, but starting in the 1980s a wave of democratization came through the continent, and democratic rule is the norm now. Allegations of corruption remain common, and several nations have seen crises which have forced the resignation of their presidents, although normal civilian succession has continued. International indebtedness became a notable problem, as most recently illustrated by Argentina's default in the early 21st century.

Economy

As of 2002, South America's gross domestic product declined by 0.3 percent, and its unemployment rate was 10.8 percent. Due to histories of high inflation in nearly all South American countries, interest rates and thus investment remain high and low, respectively. Interest rates are usually double that of the United States. For example, interest rates are about 22 percent in Venezuela and 23 percent in Suriname. The exception is Chile, which had a head start from 1973 under Augusto Pinochet. The South American Community of Nations is a planned continent-wide free trade zone to unite two existing free-trade organizations—Mercosur and the Andean Community. In South America, the gap between the rich and the poor is tremendous. In Venezuela, Paraguay, Brazil, and many other South American countries, the richest 20 percent may own over 60 percent of the nation's wealth, while the poorest 20 percent may own less than 5 percent. This wide gap can be seen in many large South American cities where makeshift shacks and slums lie next to skyscrapers and upper-class luxury apartments.

Culture

Roman Catholicism is the dominant religion. French Guiana also has a large number of Protestants. Guyana and Suriname are exceptions, with three major religions: Christianity in general, Hinduism, and Islam. Portuguese and Spanish are the primary languages of the continent. The majority of South Americans (51%) speak Portuguese. However, most South American countries are Spanish-speaking, and nearly all of the continent's lusophones reside in Brazil. Among other languages used by many South Americans are:
- Aymará in Bolivia and Peru.
- Quechua in Bolivia, Ecuador, and Peru.
- Guaraní in Paraguay.
- English in Guyana.
- Hindi in Guyana and Suriname.
- Dutch and Indonesian in Suriname.
- Italian and German in certain pockets across southern South America. South American nations have a rich variety of music. Some of the most famous genres include samba from Brazil and cumbia from Colombia. Because of South America's ethnic mix, South American cuisine takes on African, American Indian, and European influences. Bahia, Brazil, is especially well-known for its West African-influenced cuisine.

People

Ethnic groups of South America include:
- Awá
- Banawa
- Caiapos
- Enxet
- European descendants, especially from Spain, Portugal and Italy.
- Ge
- Guarani
- Incas
- Quechuas
- Juris
- Latin peoples
- Mapuche
- Mestizo
- Xucuru
- Zaparos Indigenous peoples make up the majority of the population in Bolivia and Peru, and are a significant element in most other former Spanish colonies. Exceptions to this include Argentina and Uruguay. At least three of the Amerindian languages (Quechua in Peru and Bolivia, Aymara also in Bolivia, and Guarani in Paraguay) are recognized along with Spanish as national languages. Argentina is 10 percent Indian.

Mestizos

"Mestizo" is a term of Spanish origin used to designate the peoples of mixed European and Amerindian racial strain inhabiting the region spanning the Americas. Mestizos officially make up the majority of the populations of Chile (90%), Colombia (58%), Ecuador (65%), Paraguay (95%) and Venezuela (67%). Figures in other countries are Argentina (about 13%), Bolivia (30%), Brazil (about 12%), Uruguay (8%) and Peru (37%).

African ancestry

Africans first arrived with the Spanish and Portuguese in the 16th century. Most were brought as slaves and delivered to Brazil and the Caribbean. Brazil now has about 60 million black people. Venezuela and Colombia also have significant black population. "Mulato" is a term of Spanish origin (Mulatto in English) describing Latin Americans of mixed African and White racial descent. "Zambo" is a term of Spanish origin describing Latin Americans of mixed African and Amerindian racial descent. The feminine form is zamba.

Territories and divisions

Notes:
¹ La Paz is the administrative capital of Bolivia; Sucre is the judicial seat.
² Santiago is the administrative capital of Chile; Valparaíso is the site of legislative meetings.
³ Claimed by Argentina.
⁴ The South Georgia and the South Sandwich Islands have no permanent population, only hosting a periodic contingent of about 100 researchers and visitors.
- Depending on definitions, Panama and Trinidad and Tobago have territory in one or both of South and North America.

External links

News
- [http://www.notisur.com/ NOTISUR -- Political and social news of South America (in Spanish)] Sports
- [http://www.conmebol.com/ CONMEBOL -- Confederación Sudamericana de Fútbol (The South American Footbal Confederation) in Spanish and Portuguese] Geography
- [http://www.freeworldmaps.net/southamerica/index.html Physical map of South America] South American Community of Nations Category:Continents South America zh-min-nan:Lâm Bí-chiu ko:남아메리카 ja:南アメリカ simple:South America th:ทวีปอเมริกาใต้

Leaf

:This article is about the leaf, a plant organ. See Leaf (disambiguation) for other meanings. ---- In botany, a leaf is an above-ground plant organ specialized for photosynthesis. For this purpose, a leaf is typically flat (laminar) and thin, to expose the chloroplast containing cells (chlorenchyma tissue) to light over a broad area, and to allow light to penetrate fully into the tissues. Leaves are also the sites in most plants where respiration, transpiration, and guttation take place. Leaves can store food and water, and are modified in some plants for other purposes. The comparable structures of ferns are correctly referred to as fronds. frond frond frond

Leaf anatomy

A structurally complete leaf of an angiosperm consists of a petiole (leaf stem), a lamina (leaf blade), and stipules (small processes located to either side of the base of the petiole). The point at which the petiole attaches to the stem is called the leaf axil. Not every species produces leaves with all of these structural parts. In some species, paired stipules are not obvious or are absent altogether; a petiole may be absent; or the blade may not be laminar (flattened). The tremendous variety shown in leaf structure (anatomy) from species to species is presented in detail below under Leaf types, arrangements, and forms. A leaf is considered to be a plant organ, typically consisting of the following tissues: # An epidermis that covers the upper and lower surfaces # An interior chlorenchyma called the mesophyll # An arrangement of veins (the vascular tissue). stipule

Epidermis

The epidermis is the outer multi-layered group of cells covering the leaf. It forms the boundary between the plant and the external world. The epidermis serves several functions: protection against water loss, regulation of gas exchange, secretion of metabolic compounds, and (in some species) absorption of water. Most leaves show dorsoventral anatomy: the upper (adaxial) and lower (abaxial) surfaces have somewhat different construction and may serve different functions. The epidermis is usually transparent (epidermal cells lack chloroplasts) and coated on the outer side with a waxy cuticle that prevents water loss. The cuticle may be thinner on the lower epidermis than on the upper epidermis; and is thicker on leaves from dry climates as compared with those from wet climates. The epidermis tissue includes several differentiated cell types: epidermal cells, guard cells, subsidiary cells, and epidermal hairs (trichomes). The epidermal cells are the most numerous, largest, and least specialized. These are typically more elongated in the leaves of monocots than in those of dicots. The epidermis is covered with pores called stomata (sing., stoma), part of a stoma complex consisting of a pore surrounded on each side by chloroplast-containing guard cells, and two to four subsidiary cells that lack chloroplasts. The stoma complex regulates the exchange of gases and water vapor between the outside air and the interior of the leaf. Typically, the stomata are more numerous over the abaxial (lower) epidermis than the (adaxial) upper epidermis. Trichomes or hairs grow out from the epidermis in many species.

Mesophyll

Most of the interior of the leaf between the upper and lower layers of epidermis is a parenchyma (ground tissue) or chlorenchyma tissue called the mesophyll (= middle leaf). This "assimilation tissue" is the primary location of photosynthesis in the plant. The products of photosynthesis are called assimilates. In ferns and most flowering plants the mesophyll is divided into two layers:
- An upper palisade layer of tightly packed, vertically elongated cells, one to two cells thick, directly beneath the adaxial epidermis. Its cells contain many more chloroplasts than the spongy layer. These long cylindrical cells are regularly arranged in one to five rows. Cylindrical cells, with the chloroplasts close to the walls of the cell, can take optimal advantage of light. The slight separation of the cells provides maximum absorption of carbon dioxide. This separation must be minimal to afford capillary action for water distribution. In order to adapt to their different environment (such as sun or shade), plants had to adapt this structure to obtain optimal result. Sun leaves have a multi-layered palisade layer, while shade leaves or older leaves closer to the soil, are single-layered.
- Beneath the palisade layer is the spongy layer. The cells of the spongy layer are more rounded and not so tightly packed. There are large intercellular air spaces. These cells contain less chloroplasts than those of the palisade layer. The pores or stomata of the epidermis open into substomatal chambers, connecting to air spaces between the spongy layer cells. These two different layers of the mesophyll are absent in many aquatic and marsh plants. Even an epidermis and a mesophyll may be lacking. Instead for their gaseous exchanges they use a homogenous aerenchyma (thin-walled cells separated by large gas-filled spaces). Their stomata are situated at the upper surface. Leaves are normally green in color, which comes from chlorophyll found in plastids in the chlorenchyma cells. Plants that lack chlorophyll cannot photosynthesize. Leaves in temperate, boreal, and seasonally dry zones may be seasonally deciduous (falling off or dying for the inclement season). This mechanism to shed leaves is called abscission. After the leaf is shed, a leaf scar develops on the twig. In cold autumns they sometimes turn yellow, bright orange or red as various accessory pigments (carotenoids and anthocyanins) are revealed when the tree responds to cold and reduced sunlight by curtailing chlorophyll production.

Veins

The veins are the vascular tissue of the leaf and are located in the spongy layer of the mesophyll. They are typical examples of pattern formation through ramification. The veins are made up of:
- xylem, which brings water from the stem into the leaf.
- phloem, which usually moves sap out, the latter containing the glucose produced by photosynthesis in the leaf. The xylem typically lies over the phloem. Both are embedded in a dense parenchyma tissue (= ground tissue), called pith, with usually some structural collenchyma tissue present.

Leaf morphology

External leaf characteristics (such as shape, margin, hairs, etc.) are important for identifying plant species, and botanists have developed a rich terminology for describing leaf characteristics. phloem Leaves may be classified in many different ways, and the type is usually characteristic of a species, although some species produce more than one type of leaf. The terminology associated with describing leaf morphology is presented (with illustrations) at [http://wikibooks.org/wiki/Botany:_Leaves_(forms) Wikibooks].

Basic leaf types

- Ferns have fronds.
- Conifer leaves are typically needle-, awl-, or scale-shaped
- Angiosperm (flowering plant) leaves: the standard form includes stipules, petiole, and lamina.
- Microphyll leaves.
- Sheath leaves (type found in most grasses).
- Other specialized leaves.

Arrangement on the stem

As a stem grows, leaves tend to appear arranged around the stem in away that optimizes yield of light. In essence, leaves come off the stem in a spiral pattern, either clockwise or counterclockwise, with (depending upon the species) the same angle of divergence. There is a regularity in these angles and they follow the numbers in a Fibonacci series: 1/2, 2/3, 3/5, 5/8, 8/13, 13/21, 21/34, 34/55, 55/89. This series tends to a limit of 360° x 34/89 = 137,52 or 137° 30', an angle known mathematically as the 'golden angle'. In the series, the numerator gives the number of complete turns or gyres until the leaf arrives at the initial position. The denominator gives the number of leaves in the arrangement. This can be demonstrated by the following:
- alternate leaves have an angle of 180° (or 1/2)
- 120° (or 1/3) : three leaves in one circle
- 144° (or 2/5) : five leaves in two gyres
- 135° (or 3/8) : eight leaves in three gyres. The fact that an arrangement of anything in nature can be described by a mathematical formula is not in itself mysterious. Mathematics is the science of discovering numerical relationships and applying formulae to these relationships. The formulae themselves can provide clues to the underlying physiological processes that, in this case, determine where the next leaf bud will form in the elongating stem. However, we can more easily describe the arrangement of leaves using the following terms:
- Alternate — leaf attachments singular at nodes, and leaves alternate direction, to a greater or lesser degree, along the stem.
- Opposite — leaf attachments paired at each node; decussate if, as typical, each successive pair is rotated 90° going along the stem; or distichous if not rotated, but two-ranked (in the same plane).
- Whorled — three or more leaves attach at each point or node on the stem. As with opposite leaves, successive whorls may or may not be decussate, rotated by half the angle between the leaves in the whorl (i.e., successive whorls of three rotated 60°, whorls of four rotated 45°, etc). Note: opposite leaves may appear whorled near the tip of the stem.
- Rosulate — leaves form a rosette ( = a cluster of leaves growing in crowded circles from a common center). Fibonacci series

Divisions of the lamina (blade)

Two basic forms of leaves can be described considering the way the blade is divided. A simple leaf has an undivided blade. However, the leaf shape may be one of lobes, but the gaps between lobes do not reach to the main vein. A compound leaf has a fully subdivided blade, each leaflet of the blade separated along a main or secondary vein. Because each leaflet can appear to be a "simple leaf", it is important to recognize where the petiole occurs to identify a compound leaf. Compound leaves are a characteristic of some families of higher plants, such as the Fabaceae.
- Palmately compound leaves have the leaflets radiating from the end of the petiole, like fingers off the palm of a hand. There is no rachis, e.g. Cannabis (hemp) and Aesculus (buckeyes).
- Pinnately compound leaves have the leaflets arranged along the main or mid-vein (called a rachis in this case).
- odd pinnate: with a terminal leaflet, e.g. Fraxinus (ash).
- even pinnate: lacking a terminal leaflet, e.g. Swietenia (mahogany).
- Bipinnately compound leaves are twice divided: the leaflets are arranged along a secondary vein that is one of several branching off the rachis. Each leaflet is called a pinnule. The pinnules on one secondary vein are called pinna; e.g. Albizia (silk tree).
- trifoliate: a pinnate leaf with just three leaflets, e.g. Trifolium (clover), Laburnum (laburnum).
- pinnatifid: pinnately dissected to the midrib, but with the leaflets not entirely separate, e.g. some Sorbus (whitebeams). ;Characteristics of the petiole:
- Petiolated leaves have a petiole.
- In peltate leaves, the petiole attaches to the blade inside from the blade margin.
- Sessile or clasping leaves do not have a petiole. In sessile leaves the blade attaches directly to the stem. In clasping leaves, the blade partially or wholly surrounds the stem, giving the impression that the shoot grows through the leaf such as in Claytonia perfoliata of the purslane family (Portulacaceae). In some Acacia species, such as the Koa Tree (Acacia koa), the petioles are expanded or broadened and function like leaf blades; these are called phyllodes. There may or may not be normal pinnate leaves at the tip of the phyllode. ;Characteristics of the stipule
- A stipule, present on the leaves of many dicotyledons, is an appendage on each side at the base of the petiole, resembling a small leaf. They may be lasting and not be shed (a stipulate leaf, such as in roses and beans); or be shed as the leaf expands, leaving a stipule scar on the twig (an exstipulate leaf).
- The situation, arrangement, and structure of the stipules is called the stipulation.
- free
- adnate : fused to the petiole base
- ochreate : provided with ochrea, or sheath-formed stipules, e.g. rhubarb,
- encircling the petiole base
- interpetiolar : between the petioles of two opposite leaves.
- intrapetiolar : between the petiole and the subtending stem

Venation (arrangement of the veins)

rhubarb There are two subtypes of venation, craspedodromus (the major veins stretch up to the margin of the leaf) and camptodromous (major veins come close to the margin, but bend before they get to it).
- Feather-veined, reticulate — the veins arise pinnately from a single mid-vein and subdivide into veinlets. These, in turn, form a complicated network. This type of venation is typical for dicotyledons.
- Pinnate-netted, penniribbed, penninerved, penniveined; the leaf has usually one main vein (called the mid-vein), with veinlets, smaller veins branching off laterally, usually somewhat parallel to each other; eg Malus (apples).
- Three main veins originate from the base of the lamina, as in Ceanothus.
- Palmate-netted, palmate-veined, fan-veined; several main veins diverge from near the leaf base where the petiole attaches, and radiate toward the edge of the leaf; e.g. most Acer (maples).
- Parallel-veined, parallel-ribbed, parallel-nerved, penniparallel — veins run parallel most the length of the leaf, from the base to the apex. Commissural veins (small veins) connect the major parallel veins. Typical for most monocotyledons, such as grasses.
- Dichotomous — There are no dominant bundles, with the veins forking regularly by pairs; found in Ginkgo and some pteridophytes.
pteridophyte

Leaf terminology

;Shape See Leaf shape

Margins (edge)

The leaf margin is characteristic for a genus and aids in determining the species.
- entire: even; with a smooth margin; without toothing
- ciliate: fringed with hairs
- crenate: wavy-toothed; dentate with rounded teeth, such as Fagus (beech)
- dentate: toothed, such as Castanea (chestnut)
- coarse-toothed: with large teeth
- glandular toothed: with teeth that bear glands.
- denticulate: finely toothed
- doubly toothed: each tooth bearing smaller teeth, such as Ulmus (elm)
- lobate: indented, with the indentations not reaching to the center, such as many Quercus (oaks)
- palmately lobed: indented with the indentations reaching to the center, such as Humulus (hop).
- serrate: saw-toothed with asymmetrical teeth pointing forward, such as Urtica (nettle)
- serrulate: finely serrate
- sinuate: with deep, wave-like indentations; coarsely crenate, such as many Rumex (docks)
- spiny: with stiff, sharp points, such as some Ilex (hollies) and Cirsium (thistles).

Tip of the leaf

- acuminate: long-pointed, prolonged into a narrow, tapering point in a concave manner.
- acute: ending in a sharp, but not prolonged point
- cuspidate: with a sharp, elongated, rigid tip; tipped with a cusp.
- emarginate: indented, with a shallow notch at the tip.
- mucronate: abruptly tipped with a small short point, as a continuation of the midrib; tipped with a mucro.
- mucronulate: mucronate, but with a smaller spine.
- obcordate: inversely heart-shaped, deeply notched at the top.
- obtuse: rounded or blunt
- truncate: ending abruptly with a flat end, that looks cut off.

Base of the leaf

- acuminate: coming to a sharp, narrow, prolonged point.
- acute: coming to a sharp, but not prolonged point.
- auriculate: ear-shaped
- cordate: heart-shaped with the norch away from the stem.
- cuneate: wedge-shaped.
- hastate: shaped like an halberd and with the basal lobes pointing outward.
- oblique: slanting.
- reniform: kidney-shaped but rounder and broader than long.
- rounded: curving shape.
- sagittate: shaped like an arrowhead and with the acute basal lobes pointing downward.
- truncate: ending abruptly with a flat end, that looks cut off.

Surface of the leaf

The surface of a leaf can be described by several botanical terms:
- farinose: bearing farina; mealy, covered with a waxy, whitish powder.
- glabrous: smooth, not hairy.
- glaucous: with a whitish bloom; covered with a very fine, bluish-white powder.
- glutinous: sticky, viscid.
- papillate, papillose: bearing papillae (minute, nipple-shaped protuberances).
- pubescent: covered with erect hairs (especially soft and short ones)
- punctate: marked with dots; dotted with depressions or with translucent glands or colored dots.
- rugose: deeply wrinkled; with veins clearly visible.
- scurfy: covered with tiny, broad scalelike particles.
- tuberculate: covered with tubercles; covered with warty prominences.
- verrucose: warted, with warty outgrowths.
- viscid, viscous: covered with thick, sticky secretions.

Hairiness (trichomes)

Leaves can show several degrees of hairiness. The meaning of several of the following terms can overlap. See also : Trichome.
- glabrous: no hairs of any kind present.
- arachnoid, arachnose: with many fine, entangled hairs giving a cobwebby appearance.
- barbellate: with finely barbed hairs (barbellae).
- bearded: with long, stiff hairs.
- bristly: with stiff hair-like prickles.
- canescent: hoary with dense grayish-white pubescence.
- ciliate: marginally fringed with short hairs (cilia).
- ciliolate: minutely ciliate.
- floccose: with flocks of soft, woolly hairs, which tend to rub off.
- glandular: with a gland at the tip of the hair.
- hirsute: with rather rough or stiff hairs.
- hispid: with rigid, bristly hairs.
- hispidulous: minutely hispid.
- hoary: with a fine, close grayish-white pubescence.
- lanate, lanose: with woolly hairs.
- pilose: with soft, clearly separated hairs.
- puberulent, puberulous: with fine, minute hairs.
- pubescent: with soft, short and erect hairs.
- scabrous, scabrid: rough to the touch
- sericeous: silky appearance through fine, straight and appressed (lying close and flat) hairs.
- silky: with adpressed, soft and straight pubescence.
- stellate, stelliform: with star-shaped hairs.
- strigose: with appressed, sharp, straight and stiff hairs.
- tomentose: densely pubescent with matted, soft white woolly hairs.
- cano-tomentose: between canescent and tomentose
- felted-tomentose: woolly and matted with curly hairs.
- villous: with long and soft hairs, usually curved.
- woolly: with long, soft and tortuous or matted hairs.

Adaptations

In order to survive in a harsh environment, leaves can adapt in the following ways:
- Hairs develop on the leaf surface to trap humidity in dry climates, creating a large boundary layer to lessen water loss
- Leaves rustle to move humidity away from the surface reducing the boundary layer resistance between the leaf and the air.
- Plant prickles are modified clusters of epidermal hairs
- Waxy leaf surfaces form to prevent water loss
- Small, shiny leaves to deflect the sun's rays
- Thicker leaves to store water (e.g. rhubarb)
- Change to spines instead of laminar (blade) leaves (e.g. cactus)
- Shrink (to phyllodes) or disappear (with the appearance of cladodes), as photosynthetic functions are transferred to the leaf stem (Acacia species)
- Change shape to deflect wind or reduce wind resistance
- Leaves to trap insects (e.g. pitcher plant)
- Change to bulb parts to store food (e.g. onion)
- Produce aromatic oils to deter herbivores (e.g. eucalypts)
- Protect as spines, which are modified leaves.

External links

- [http://www.ibiblio.org/botnet/glossary/b_i.html Position and Arrangement] Category:Photosynthesis Category:Plant physiology Category:plant morphology Category:Plant anatomy ko:잎 ja:葉 th:ใบไม้

Flower

:This article is about the plants; for other uses see Flower (disambiguation). Flower (disambiguation) Flower (Latin flos, floris; French fleur), a term popularly used for the bloom or blossom of a plant, is the reproductive structure of those plants classified as angiosperms (flowering plants; Division Magnoliophyta). The flower structure incorporates the reproductive organs, and its function is to produce seeds through sexual reproduction. For the higher plants, seeds are the next generation, and serve as the primary means by which individuals of a species are dispersed across the landscape. After fertilization, portions of the flower develop into a fruit containing the seed(s).

Flower anatomy

Flowering plants are heterosporangiate (producing two types of reproductive spores) and the pollen (male spores) and ovules (female spores) are produced in different organs, but these are together in a bisporangiate strobilus that is the typical flower. A flower is regarded as a modified stem (Eames, 1961) with shortened internodes and bearing, at its nodes, structures that may be highly modified leaves. In essence, a flower structure forms on a modified shoot or axis with an apical meristem that does not grow continuously (growth is determinate). The stem is called a pedicel, the end of which is the torus or receptacle. The parts of a flower are arranged in whorls on the torus. The four main parts or whorls (starting from the base of the flower or lowest node and working upwards) are as follows: flower
- calyx – the outer whorl of sepals; typically these are green, but are petal-like in some species.
- corolla – the whorl of petals, which are usually thin, soft and colored to attract insects that help the process of pollination.
- androecium (from Greek andros oikia: man's house) – one or two whorls of stamens, each a filament topped by an anther where pollen is produced. Pollen contains the male gametes.
- gynoecium (from Greek gynaikos oikia: woman's house) – one or more pistils. The female reproductive organ is the carpel: this contains an ovary with ovules (female gametes). A pistil may consist of a number of carpels merged together, in which case there is only one pistil to each flower, or of a single individual carpel (the flower is then called apocarpous). The sticky tip of the pistil, the stigma, is the receptor of pollen. The supportive stalk, the style becomes the pathway for pollen tubes to grow from pollen grains adhering to the stigma, to the ovules, carrying the reproductive material. carpel Although the floral structure described above is considered the "typical" structural plan, plant species show a wide variety of modifications from this plan. These modifications have significance in the evolution of flowering plants and are used extensively by botanists to establish relationships among plant species. For example, the two subclasses of flowering plants may be distinguished by the number of floral organs in each whorl: dicotyledons typically having 4 or 5 organs (or a multiple of 4 or 5) in each whorl and monocotyledons having three or some multiple of three. The number of carpels in a compound pistil may be only two, or otherwise not related to the above generalization for monocots and dicots. In the majority of species, individual flowers have both pistils and stamens as described above. These flowers are described by botanists as being perfect, bisexual, or hermaphrodite. However, in some species of plants the flowers are imperfect or unisexual: having only either male (stamens) or female (pistil) parts. In the latter case, if an individual plant is either male or female the species is regarded as dioecious. However, where unisexual male and female flowers appear on the same plant, the species is considered monoecious. Some flowers with both stamens and a pistil are capable of self-fertilization, which does increase the chance of producing seeds but limits genetic variation. The extreme case of self-fertilization occurs in flowers that always self-fertilize, such as the common dandelion. Conversely, many species of plants have ways of preventing self-fertilization. Unisexual male and female flowers on the same plant may not appear at the same time, or pollen from the same plant may be incapable of fertilizing its ovules. The latter flower types, which have chemical barriers to their own pollen, are referred to as self-sterile or self-incompatible. (See also: Plant sexuality) Plant sexuality Additional discussions on floral modifications from the basic plan are presented in the articles on each of the basic parts of the flower. In those species that have more than one flower on an axis, the collection of flowers is termed an inflorescence. In this sense, care must be exercised in considering what is a flower. In botanical terminology, a single daisy or sunflower for example, is not a flower but a flower head—an inflorescence comprised of numerous small flowers (sometimes called florets). Each small flower may be anatomically as described above.

Floral formula

A floral formula is a way to represent the structure of a flower using specific letters, numbers, and symbols. Typically, a general formula will be used to represent the flower structure of a plant family rather than a particular species. The following representations are used: Ca = calyx (sepal whor