Hectare
The hectare is an SI accepted metric system unit of area equal to a square with 100-metre sides, or 10,000 m2, is used in the measurement of land. There are 100 hectares in one square kilometre. An acre is about 0.405 hectare and one hectare contains about 2.47 acres. In 1795, when the metric system was introduced, the "are" was defined as 100 square metres and the hectare was thus 100 "ares" or 1⁄100 km2; when the metric system was further rationalised in 1960, resulting in the International System of Units, the are was not included as a recognised unit. The hectare, remains as a non-SI unit accepted for use with the SI units, mentioned in Section 4.1 of the SI Brochure as a unit whose use is "expected to continue indefinitely". The name was coined from the Latin ārea; the metric system of measurement was first given a legal basis in 1795 by the French Revolutionary government. The law of 18 Germinal, Year III defined five units of measure: The metre for length The are for area The stère for volume of stacked firewood The litre for volumes of liquid The gram for massIn 1960, when the metric system was updated as the International System of Units, the are did not receive international recognition.
The International Committee for Weights and Measures makes no mention of the are in the current definition of the SI, but classifies the hectare as a "Non-SI unit accepted for use with the International System of Units". In 1972, the European Economic Community passed directive 71/354/EEC, which catalogued the units of measure that might be used within the Community; the units that were catalogued replicated the recommendations of the CGPM, supplemented by a few other units including the are whose use was limited to the measurement of land. The names centiare, deciare and hectare are derived by adding the standard metric prefixes to the original base unit of area, the are; the centiare is one square metre. The deciare is ten square metres; the are is a unit of area, used for measuring land area. It was defined by older forms of the metric system, but is now outside the modern International System of Units, it is still used in colloquial speech to measure real estate, in particular in Indonesia, in various European countries.
In Russian and other languages of the former Soviet Union, the are is called sotka. It is used to describe the size of suburban dacha or allotment garden plots or small city parks where the hectare would be too large; the decare is derived from deca and are, is equal to 10 ares or 1000 square metres. It is used in Norway and in the former Ottoman areas of the Middle East and the Balkans as a measure of land area. Instead of the name "decare", the names of traditional land measures are used, redefined as one decare: Stremma in Greece Dunam, donum, or dönüm in Israel, Jordan, Lebanon and Turkey Mål is sometimes used for decare in Norway, from the old measure of about the same area; the hectare, although not a unit of SI, is the only named unit of area, accepted for use within the SI. In practice the hectare is derived from the SI, being equivalent to a square hectometre, it is used throughout the world for the measurement of large areas of land, it is the legal unit of measure in domains concerned with land ownership and management, including law, agriculture and town planning throughout the European Union.
The United Kingdom, United States, to some extent Canada use the acre instead. Some countries that underwent a general conversion from traditional measurements to metric measurements required a resurvey when units of measure in legal descriptions relating to land were converted to metric units. Others, such as South Africa, published conversion factors which were to be used "when preparing consolidation diagrams by compilation". In many countries, metrication clarified existing measures in terms of metric units; the following legacy units of area have been redefined as being equal to one hectare: Jerib in Iran Djerib in Turkey Gong Qing in Hong Kong / mainland China Manzana in Argentina Bunder in The Netherlands The most used units are in bold. One hectare is equivalent to: 1 square hectometre 15 mǔ or 0.15 qǐng 10 dunam or dönüm 10 stremmata 6.25 rai ≈ 1.008 chō ≈ 2.381 feddan Conversion of units Hecto- Hectometre Order of magnitude Official SI website: Table 6. Non-SI units accepted for use with the International System of Units
Ganna Walska
Ganna Walska was a Polish opera singer and garden enthusiast who created the Lotusland botanical gardens at her mansion in Montecito, California. She was married four times to wealthy husbands; the lavish promotion of her lackluster opera career by her fourth husband, Harold Fowler McCormick, inspired aspects of the screenplay for Citizen Kane. Ganna Walska was born Hanna Puacz on 26 June 1887 in Brest, Russian Empire to Polish parents Napoleon Puacz and Karolina Massalska. Ganna is a Russian form of Hannah, Walska "reminiscent of her favorite music, the waltz". In 1922, after her marriage to Harold F. McCormick, Ganna Walska purchased the Théâtre des Champs-Élysées in Paris, she told the Chicago Tribune that she had invested her own funds, not those of her wealthy husband, said, "I will never appear in my own theatre until I have gained recognition based on my merits as an artist."Walska pursued a career as an opera singer. The lavish promotion of her opera career by McCormick—despite her apparent reputation as a mediocre singer—inspired aspects of the screenplay for Orson Welles's Citizen Kane.
Roger Ebert, in his DVD commentary on Citizen Kane, suggests that the character of Susan Alexander was based on Walska. McCormick spent thousands of dollars on voice lessons for her and arranged for Walska to take the lead in a production of Zazà by Ruggero Leoncavallo at the Chicago Opera in 1920. Walska got into an argument with director Pietro Cimini during dress rehearsal and stormed out of the production before she appeared. Contemporaries said. New York Times headlines of the day read, "Ganna Walska Fails as Butterfly: Voice Deserts Her Again When She Essays Role of Puccini's Heroine", "Mme. Walska Clings to Ambition to Sing". "According to her 1943 memoirs, Always Room at the Top, Walska had tried every sort of fashionable mumbo jumbo to conquer her nerves and salvage her voice," reported The New York Times in 1996. "Nothing worked. During a performance of Giordano's Fedora in Havana she veered so persistently off key that the audience pelted her with rotten vegetables, it was an event that Orson Welles remembered when he began concocting the character of the newspaper publisher's second wife for Citizen Kane."In 1926 Walska purchased the Duchess of Marlborough Fabergé egg, offered by Consuelo Vanderbilt at a charity auction.
It was acquired by Malcolm Forbes as the first Easter egg in his Fabergé egg collection. Ganna Walska died on March 2, 1984, at Lotusland, leaving her garden and her fortune to the Ganna Walska Lotusland Foundation. Ganna Walska was married six times: Russian baron, Arcadie d'Eingorn, a Russian officer killed early in World War I, they married in 1904 but the marriage was dissolved two years later. The baron died of tuberculosis in 1915. Dr. Joseph Fraenkel, a New York endocrinologist, they were married in 1916, he died in April 1920. Multimillionaire sportsman and carpet tycoon Alexander Smith Cochran, they married in September 1920, divorced in 1922. He died in 1929. Industrialist Harold Fowler McCormick, they married August 1922 at the City Hall in Passy in Paris. They divorced in 1931, he died in 1941. English inventor of a death ray, Harry Grindell Matthews, they married in 1938 and he died in 1941. Theos Bernard, her sixth and last husband, he was a scholar of yoga and Tibetan Buddhism and book author.
They married in 1942 and divorced in 1946. He died in 1947. In 1941, with the encouragement of her sixth husband Theos Bernard, she purchased the historic 37-acre "Cuesta Linda" estate in Montecito near Santa Barbara, intending to use it as a retreat for Tibetan monks. Due to restrictions on wartime visas, the monks were unable to come to the United States. After her divorce from Bernard in 1946, Walska changed the name of her estate to Lotusland and the lotus growing in several of her garden's ponds, she devoted the rest of her life to designing, redesigning and maintaining the estate's renowned innovative and extensive gardens. Her landscape design talent is well regarded for distinctive gardens of exceptional creativity. Gold Cross of Merit from the Polish government in 1931 Légion d'honneur order from the French government in 1934 L'Ordre National des Arts et des Letters from the French government in 1972 Adams, Brian. Ganna: Diva of Lotusland. CreateSpace. ISBN 978-1-5141-6957-5. Ganna Walska on IMDb Ganna Walska Lotusland, Frommer's Review Lotusland history "Chicago's Citizen Kane" at the Wayback Machine About Citizen Kane — Archived October 22, 2007, at the Wayback Machine Kiester, Edwin Jr.
"Not your average backyard gardener". Smithsonian Magazine, March 1997 McPherson, Sean K. "Enemy of the Average." The New York Times, April 14, 2002 Swartley, Ariel, "A diva who loved high drama." Los Angeles Times, March 10, 2005
Queensland
Queensland is the second-largest and third-most populous state in the Commonwealth of Australia. Situated in the north-east of the country, it is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Pacific Ocean. To its north is the Torres Strait, with Papua New Guinea located less than 200 km across it from the mainland; the state is the world's sixth-largest sub-national entity, with an area of 1,852,642 square kilometres. As of 15 May 2018, Queensland has a population of 5,000,000, concentrated along the coast and in the state's South East; the capital and largest city in the state is Australia's third-largest city. Referred to as the "Sunshine State", Queensland is home to 10 of Australia's 30 largest cities and is the nation's third-largest economy. Tourism in the state, fuelled by its warm tropical climate, is a major industry. Queensland was first inhabited by Torres Strait Islanders.
The first European to land in Queensland was Dutch navigator Willem Janszoon in 1606, who explored the west coast of the Cape York Peninsula near present-day Weipa. In 1770, Lieutenant James Cook claimed the east coast of Australia for the Kingdom of Great Britain; the colony of New South Wales was founded in 1788 by Governor Arthur Phillip at Sydney. Queensland was explored in subsequent decades until the establishment of a penal colony at Brisbane in 1824 by John Oxley. Penal transportation ceased in 1839 and free settlement was allowed from 1842; the state was named in honour of Queen Victoria, who on 6 June 1859 signed Letters Patent separating the colony from New South Wales. Queensland Day is celebrated annually statewide on 6 June. Queensland was one of the six colonies which became the founding states of Australia with federation on 1 January 1901; the history of Queensland spans thousands of years, encompassing both a lengthy indigenous presence, as well as the eventful times of post-European settlement.
The north-eastern Australian region was explored by Dutch and French navigators before being encountered by Lieutenant James Cook in 1770. The state has witnessed frontier warfare between European settlers and Indigenous inhabitants, as well as the exploitation of cheap Kanaka labour sourced from the South Pacific through a form of forced recruitment known at the time as "blackbirding"; the Australian Labor Party has its origin as a formal organisation in Queensland and the town of Barcaldine is the symbolic birthplace of the party. June 2009 marked the 150th anniversary of its creation as a separate colony from New South Wales. A rare record of early settler life in north Queensland can be seen in a set of ten photographic glass plates taken in the 1860s by Richard Daintree, in the collection of the National Museum of Australia; the Aboriginal occupation of Queensland is thought to predate 50,000 BC via boat or land bridge across Torres Strait, became divided into over 90 different language groups.
During the last ice age Queensland's landscape became more arid and desolate, making food and other supplies scarce. This led to the world's first seed-grinding technology. Warming again made the land hospitable, which brought high rainfall along the eastern coast, stimulating the growth of the state's tropical rainforests. In February 1606, Dutch navigator Willem Janszoon landed near the site of what is now Weipa, on the western shore of Cape York; this was the first recorded landing of a European in Australia, it marked the first reported contact between European and Aboriginal Australian people. The region was explored by French and Spanish explorers prior to the arrival of Lieutenant James Cook in 1770. Cook claimed the east coast under instruction from King George III of the United Kingdom on 22 August 1770 at Possession Island, naming Eastern Australia, including Queensland,'New South Wales'; the Aboriginal population declined after a smallpox epidemic during the late 18th century. In 1823, John Oxley, a British explorer, sailed north from what is now Sydney to scout possible penal colony sites in Gladstone and Moreton Bay.
At Moreton Bay, he found the Brisbane River. He established a settlement at what is now Redcliffe; the settlement known as Edenglassie, was transferred to the current location of the Brisbane city centre. Edmund Lockyer discovered outcrops of coal along the banks of the upper Brisbane River in 1825. In 1839 transportation of convicts was ceased, culminating in the closure of the Brisbane penal settlement. In 1842 free settlement was permitted. In 1847, the Port of Maryborough was opened as a wool port; the first free immigrant ship to arrive in Moreton Bay was the Artemisia, in 1848. In 1857, Queensland's first lighthouse was built at Cape Moreton. A war, sometimes called a "war of extermination", erupted between Aborigines and settlers in colonial Queensland; the Frontier War was notable for being the most bloody in Australia due to Queensland's larger pre-contact indigenous population when compared to the other Australian colonies. About 1,500 European settlers and their alli
Agathis robusta
Agathis robusta, the Queensland kauri pine or smooth-barked kauri, is a coniferous tree in the family Araucariaceae. It has a disjunct distribution, occurring in Queensland, Australia. Populations in Papua New Guinea may be treated as the distinct species Agathis spathulata. Agathis robusta occurs in two localities, a southern population on Fraser Island and around Maryborough, a northern population on the Atherton Tableland west of Cairns, it is a large evergreen tree growing straight and tall to a height of 30–50 m, with smooth, scaly bark. The leaves are 5–12 cm long and 2–5 cm broad and leathery in texture, with no midrib; the seed cones are globose, 8–13 cm diameter, mature in 18–20 months after pollination. The male cones are cylindrical, 5–10 cm long and 1-1.5 cm thick. The Queensland kauri was logged in the past, spectacular trees of prodigious size are much rarer than in pre-European times. Agathis robusta; the Gymnosperm Database
Araucaria bidwillii
Araucaria bidwillii, the bunya pine, is a large evergreen coniferous tree in the plant family Araucariaceae. It is found in south-east Queensland Australia and two small disjunct populations in north eastern Queensland's World Heritage listed Wet Tropics. There are many old planted specimens in New South Wales, around the Perth, Western Australia metropolitan area, they can grow up to 30–45 m. The tallest presently living is one in Bunya Mountains National Park, Queensland, reported by Robert Van Pelt in January 2003 to be 169 feet in height; the bunya pine is the last surviving species of the Section Bunya of the genus Araucaria. This section was diverse and widespread during the Mesozoic with some species having cone morphology similar to A. bidwillii, which appeared during the Jurassic. Fossils of Section Bunya are found in South America and Europe; the scientific name honours the botanist John Carne Bidwill, who came across it in 1842 and sent the first specimens to Sir William Hooker in the following year.
Native in Queensland trees were found in populations recorded as abundant and widespread in suitable habitats of South East Queensland and Wide Bay-Burnett. In these regions of Queensland the natural ecosystems growing Bunya Pines have sustained European agricultural occupation and have been fragmented now into the areas of the Blackall Range, Bunya Mountains, upper Brisbane River reaches and upper Mary River valley. Natural ecosystems having Bunya pines are found again 1,000 km to the north, in the wet tropics region of north eastern Queensland. There the species natural populations are rare and restricted. Two outlying restricted populations are known in the Cannabullen Falls and Mt. Lewis areas. A. Bidwillii has a limited distribution within Australia in part because of the drying out of Australia with loss of rainforest and poor seed dispersal; the remnant sites at the Bunya Mountains and Mount Lewis in Queensland have genetic diversity. The cones are large, soft-shelled and nutritious and fall intact to the ground beneath the tree before dehiscing.
The suggestion that extinct large animals – dinosaurs and large mammals – may have been dispersers for the Bunya is reasonable, given the seeds' size and energy content, but difficult to confirm given the incompleteness of the fossil record for coprolites. At the start of European occupation, A. bidwillii occurred in great abundance in southern Queensland, to the extent that a Bunya Bunya Reserve was declared in 1840 to protect its habitat. The tree once grew as large groves or sprinkled as an emergent species throughout other forest types on the Upper Stanley and Brisbane Rivers, Sunshine Coast hinterland, towards and on the Bunya Mountains. Today, the species is encountered as small groves or single trees in its former range, except on and near the Bunya Mountains, where it is still prolific. A. bidwillii has unusual cryptogeal seed germination in which the seeds develop to form an underground tuber from which the aerial shoot emerges. The actual emergence of the seed is known to occur over several years as a strategy to allow the seedlings to emerge under optimum climatic conditions or, it has been suggested, to avoid fire.
This erratic germination has been one of the main problems in silviculture of the species. The cones are 20–35 cm in diameter, can weigh as much as 18 kg and are opened by large birds, such as cockatoos, or disintegrate when mature to release the large 3–4 cm seeds or nuts. Although there are no reported dispersal agents for the seeds of A. bidwillii and various species of rats are known as predators of the seeds and tubers. The bush rat was observed caching bunya seeds some distance uphill from parent trees allowing ridge-top germination. Brushtail possums were mentioned as carrying the seeds up trees. In a study in 2006, the short-eared possum was shown to disperse the seed of A. bidwillii. Natural populations of this species have been reduced in extent and abundance through exploitation for its timber, the construction of dams and historical clearing. Most populations are now protected in formal reserves and national parks. A recent problem in small forestry plantations of A. bidwilli in Southeast Queensland is the introduction of red deer.
Red deer, unlike possums and rodents, eat bunya cones while still intact, preventing their dispersal. The bunya, bunyi or bunya-bunya in various Australian Aboriginal languages was colloquially named the Bunya Pine by Europeans. However, Araucaria bidwillii is not a pine tree, it belongs to the same genus as the monkey puzzle tree and is referred to as the "false monkey puzzle". The Bunya tree grows to a height of 30–45 metres, the cones, which contain the edible kernels, are the size of footballs; the ripe cones fall to the ground. Each segment contains a kernel in a tough protective shell, which will split when boiled or put in a fire; the flavour of the kernel is similar to a chestnut. A Bunya festival was recorded by Thomas Petrie, who went with the Aboriginal people of Brisbane at the age of 14 to the festival at the Bunya Range, his daughter, Constance Petrie, put down his stories in which he said that the trees fruited at three-year intervals. The three-year interval may not be correct. Ludwig Leichhardt wrote in 1844 of his expedition to the Bunya feast.
The 1889 book'The Useful Native Plants of Australia' records that "The cones shed their seeds, which are two to
Cedrus libani
Cedrus libani known as the cedar of Lebanon or Lebanon cedar, is a species of cedar native to the mountains of the Eastern Mediterranean basin. It is an evergreen conifer, it is the national emblem of Lebanon and is used as an ornamental tree in parks and gardens. C. libani is an evergreen coniferous tree. It can reach 40 m in height with a massive monopodial columnar trunk up to 2.5 m in diameter. The trunks of old trees ordinarily fork into several erect branches; the rough and scaly bark is dark grey to blackish brown, is run through by deep, horizontal fissures that peel in small chips. The first-order branches are ascending in young trees. Second-order branches grow in a horizontal plane; the crown is conical when young, becoming broadly tabular with age with level branches. The shoots are dimorphic, with both short shoots. New shoots are pale brown, older shoots turn grey and scaly. C. libani has resinous ovoid vegetative buds measuring 2 to 3 mm long and 1.5 to 2 mm wide enclosed by pale brown deciduous scales.
The leaves are needle-like, arranged in spirals and concentrated at the proximal end of the long shoots, in clusters of 15–35 on the short shoots. Cedrus libani produces cones at around the age of 40. Male cones occur at the ends of the short shoots; the female seed cones grow at the terminal ends of short shoots. The young seed cones are resinous and pale green; the mature, woody cones are 3 to 6 cm wide. Mature cones open from top to bottom, they disintegrate and lose their seed scales, releasing the seeds until only the cone rachis remains attached to the branches; the seed scales are thin and coriaceous, measuring 3.5 to 4 cm long and 3 to 3.5 cm wide. The seeds are ovoid, 10 to 14 mm long and 4 to 6 mm wide, attached to a light brown wedge-shaped wing, 20 to 30 mm long and 15 to 18 mm wide. C. libani grows until the age of 45 to 50 years. Cedrus is the Latin name for true cedars; the specific epithet refers the Lebanon mountain range where the species was first described by French botanist Achille Richard.
Two distinct types are recognized as varieties: C. libani var. libani and C. libani var. brevifolia. C. Libani var. libani: Lebanon cedar, cedar of Lebanon – grows in Lebanon, western Syria, south-central Turkey. C. libani var. stenocoma, considered a subspecies in earlier literature, is now recognized as an ecotype of C. libani var. libani. It has a spreading crown that does not flatten; this distinct morphology is a habit, assumed to cope with the competitive environment, since the tree occurs in dense stands mixed with the tall-growing Abies cilicica, or in pure stands of young cedar trees. C. Libani var. brevifolia: The Cyprus cedar occurs on the island's Troodos Mountains. This taxon was considered a separate species from C.libani because of morphological and ecophysiological trait differences. It is characterized by slow growth, shorter needles, higher tolerance to drought and aphids. Genetic relationship studies, did not recognize C. brevifolia as a separate species, the markers being undistinguishable from those of C. libani.
C. libani var. libani is endemic to elevated mountains around the Eastern Mediterranean in Lebanon and Turkey. The tree grows in well-drained calcareous lithosols on rocky, north- and west-facing slopes and ridges and thrives in rich loam or a sandy clay in full sun, its natural habitat is characterized by warm, dry summers and cool, moist winters with an annual precipitation of 1,000 to 1,500 mm. In Lebanon and Turkey, it occurs most abundantly at altitudes of 1,300 to 3,000 m, where it forms pure forests or mixed forests with Cilician fir, European black pine, eastern Mediterranean pine, several juniper species. In Turkey, it can occur as low as 500 m. C. libani var. brevifolia grows in similar conditions on medium to high mountains in Cyprus from altitudes ranging from 900 to 1,525 m. The Lebanon cedar is mentioned several times in the Tanakh. Hebrew priests were ordered by Moses to use the bark of the Lebanon cedar in the treatment of leprosy. Solomon procured cedar timber to build the Temple in Jerusalem.
The Hebrew prophet Isaiah used the Lebanon cedar as a metaphor for the pride of the world, with the tree explicitly mentioned near the end of Psalm 92 as a symbol of the righteous. The Lebanon cedar is the national emblem of Lebanon, is displayed on the flag of Lebanon and coat of arms of Lebanon, it is the logo of Middle East Airlines, Lebanon's national carrier. Beyond that, it is the main symbol o
Oak
An oak is a tree or shrub in the genus Quercus of the beech family, Fagaceae. There are 600 extant species of oaks; the common name "oak" appears in the names of species in related genera, notably Lithocarpus, as well as in those of unrelated species such as Grevillea robusta and the Casuarinaceae. The genus Quercus is native to the Northern Hemisphere, includes deciduous and evergreen species extending from cool temperate to tropical latitudes in the Americas, Asia and North Africa. North America contains the largest number of oak species, with 90 occurring in the United States, while Mexico has 160 species of which 109 are endemic; the second greatest center of oak diversity is China, which contains 100 species. Oaks have spirally arranged leaves, with lobate margins in many species. Many deciduous species are marcescent. In spring, a single oak tree produces small female flowers; the fruit is a nut called an oak nut borne in a cup-like structure known as a cupule. The acorns and leaves contain tannic acid, which helps to guard from insects.
The live oaks are distinguished for being evergreen, but are not a distinct group and instead are dispersed across the genus. The oak tree is a flowering plant. Oaks may be divided into two genera and a number of sections: The genus Quercus is divided into the following sections: Sect. Quercus, the white oaks of Europe and North America. Styles are short; the leaves lack a bristle on their lobe tips, which are rounded. The type species is Quercus robur. Sect. Mesobalanus, Hungarian oak and its relatives of Europe and Asia. Styles long; the section Mesobalanus is related to section Quercus and sometimes included in it. Sect. Cerris, the Turkey oak and its relatives of Europe and Asia. Styles long; the inside of the acorn's shell is hairless. Its leaves have sharp lobe tips, with bristles at the lobe tip. Sect. Protobalanus, the canyon live oak and its relatives, in southwest United States and northwest Mexico. Styles short, acorns mature in 18 months and taste bitter; the inside of the acorn shell appears woolly.
Leaves have sharp lobe tips, with bristles at the lobe tip. Sect. Lobatae, the red oaks of North America, Central America and northern South America. Styles long; the inside of the acorn shell appears woolly. The actual nut is encased in a thin, papery skin. Leaves have sharp lobe tips, with spiny bristles at the lobe; the ring-cupped oaks of eastern and southeastern Asia. Evergreen trees growing 10–40 m tall, they are distinct from subgenus Quercus in that they have acorns with distinctive cups bearing concrescent rings of scales. IUCN, ITIS, Encyclopedia of Life and Flora of China treats Cyclobalanopsis as a distinct genus, but some taxonomists consider it a subgenus of Quercus, it contains about 150 species. Species of Cyclobalanopsis are common in the evergreen subtropical laurel forests which extend from southern Japan, southern Korea, Taiwan across southern China and northern Indochina to the eastern Himalayas, in association with trees of genus Castanopsis and the laurel family. Interspecific hybridization is quite common among oaks but between species within the same section only and most common in the white oak group.
Inter-section hybrids, except between species of sections Mesobalanus, are unknown. Recent systematic studies appear to confirm a high tendency of Quercus species to hybridize because of a combination of factors. White oaks are unable to discriminate against pollination by other species in the same section; because they are wind pollinated and they have weak internal barriers to hybridization, hybridization produces functional seeds and fertile hybrid offspring. Ecological stresses near habitat margins, can cause a breakdown of mate recognition as well as a reduction of male function in one parent species. Frequent hybridization among oaks has consequences for oak populations around the world. Frequent hybridization and high levels of introgression have caused different species in the same populations to share up to 50% of their genetic information. Having high rates of hybridization and introgression produces genetic data that does not differentiate between two morphologically distinct species, but instead differentiates populations.
Numerous hypotheses have been proposed to explain how oak species are able to remain morphologically and ecologically distinct with such high levels of gene flow, but the phenomenon is still a mystery to botanists. The Fagaceae, or beech family, to which the oaks belong, is a slow evolving clade compared to other angiosperms, the patterns of hybridization and introgression in Quercus pose a gre
