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Cyclobalanopsis
An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably '' Lithocarpus'' (stone oaks), as well as in those of unrelated species such as '' Grevillea robusta'' (silky oaks) and the Casuarinaceae (she-oaks). The genus ''Quercus'' is native to the Northern Hemisphere, and includes deciduous and evergreen species extending from cool temperate to tropical latitudes in the Americas, Asia, Europe, and North Africa. North America has the largest number of oak species, with approximately 160 species in Mexico of which 109 are endemic and about 90 in the United States. The second greatest area of oak diversity is China, with approximately 100 species. Description Oaks have spirally arranged leaves, with lobate margins in many species; some have serrated leaves or entire leaves with smooth ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quercus 20180406 100657
An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''Lithocarpus'' (stone oaks), as well as in those of unrelated species such as ''Grevillea robusta'' (silky oaks) and the Casuarinaceae (she-oaks). The genus ''Quercus'' is native to the Northern Hemisphere, and includes deciduous and evergreen species extending from temperateness, cool temperate to tropical latitudes in the Americas, Asia, Europe, and North Africa. North America has the largest number of oak species, with approximately 160 species in Mexico of which 109 are endemic and about 90 in the United States. The second greatest area of oak diversity is China, with approximately 100 species. Description Oaks have spirally arranged Leaf, leaves, with Dentate leaf, lobate margins in many species; some have serrated leaves or enti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Quercus Species
The genus ''Quercus'' contains about 500 species, some of which are listed here. The genus, as is the case with many large genera, is divided into subgenera and sections. Traditionally, the genus ''Quercus'' was divided into the two subgenera ''Cyclobalanopsis'', the ring-cupped oaks, and ''Quercus'', which included all the other sections. However, a comprehensive revision in 2017 identified different relationships. Now the genus is commonly divided into a subgenus ''Quercus'' and a sugenus ''Cerris'', with ''Cyclobalanopsis'' included in the latter. The sections of subgenus ''Quercus'' are mostly native to the New World, with the notable exception of the white oaks of sect. ''Quercus'' and the endemic Quercus pontica. In contrast, the sections of the subgenus ''Cerris'' are exclusively native to the Old World. Legend Species with evergreen foliage ("live oaks") are tagged '#'. Species in the genus have been recategorized between deciduous and evergreen on numerous occasions, alt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fagaceae
The Fagaceae are a family of flowering plants that includes beeches, chestnuts and oaks, and comprises eight genera with about 927 species. Fagaceae in temperate regions are mostly deciduous, whereas in the tropics, many species occur as evergreen trees and shrubs. They are characterized by alternate simple leaves with pinnate venation, unisexual flowers in the form of catkins, and fruit in the form of cup-like (cupule) nuts. Their leaves are often lobed and both petioles and stipules are generally present. Their fruits lack endosperm and lie in a scaly or spiny husk that may or may not enclose the entire nut, which may consist of one to seven seeds. In the oaks, genus ''Quercus'', the fruit is a non-valved nut (usually containing one seed) called an acorn. The husk of the acorn in most oaks only forms a cup in which the nut sits. Other members of the family have fully enclosed nuts. Fagaceae is one of the most ecologically important woody plant families in the Northern Hemispher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleocene
The Paleocene, ( ) or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name is a combination of the Ancient Greek ''palaiós'' meaning "old" and the Eocene Epoch (which succeeds the Paleocene), translating to "the old part of the Eocene". The epoch is bracketed by two major events in Earth's history. The K–Pg extinction event, brought on by Chicxulub impact, an asteroid impact and possibly volcanism, marked the beginning of the Paleocene and killed off 75% of living species, most famously the non-avian dinosaurs. The end of the epoch was marked by the Paleocene–Eocene Thermal Maximum (PETM), which was a major climatic event wherein about 2,500–4,500 gigatons of carbon were released into the atmosphere and ocean systems, causing a spike in global temperatures and ocean acidification. In the Pal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tropical
The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to as the tropical zone and the torrid zone (see geographical zone). In terms of climate, the tropics receive sunlight that is more direct than the rest of Earth and are generally hotter and wetter as they aren't affected as much by the solar seasons. The word "tropical" sometimes refers to this sort of climate in the zone rather than to the geographical zone itself. The tropical zone includes deserts and snow-capped mountains, which are not tropical in the climatic sense. The tropics are distinguished from the other climatic and biomatic regions of Earth, which are the middle latitudes and the polar regions on either side of the equatorial zone. The tropics constitute 40% of Earth's surface area and contain 36% of Earth's landmass. , the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoecious
Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system alongside gynomonoecy, andromonoecy and trimonoecy. Monoecy is connected to anemophily. It can prevent self-pollination in an individual flower but cannot prevent self-pollination between male and female flowers on the same plant. Monoecy in angiosperms has been of interest for evolutionary biologists since Charles Darwin. Terminology Monoecious comes from the Greek words for one house. History The term monoecy was first introduced in 1735 by Carl Linnaeus. Darwin noted that the flowers of monoecious species sometimes showed traces of the opposite sex function. Monoecious hemp was first reported in 1929. Occurrence Monoecy is most common in temperate climates and is often associated with inefficient pollinators or wind-pollinated plants. It may be beneficial to reducing pollen-stigma interferenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catkin
A catkin or ament is a slim, cylindrical flower cluster (a spike), with inconspicuous or no petals, usually wind-pollinated (anemophilous) but sometimes insect-pollinated (as in ''Salix''). They contain many, usually unisexual flowers, arranged closely along a central stem that is often drooping. They are found in many plant families, including Betulaceae, Fagaceae, Moraceae, and Salicaceae. Occurrence Catkin-bearing plants include many trees or shrubs such as birch, willow, aspen, hickory, sweet chestnut, and sweetfern (''Comptonia''). In many of these plants, only the male flowers form catkins, and the female flowers are single ( hazel, oak), a cone (alder), or other types (mulberry). In other plants (such as poplar), both male and female flowers are borne in catkins. In Britain, they can be seen in January or February, when many trees are bare for winter. They can even occur in December. Evolution For some time, catkins were believed to be a key synapomorphy among the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marcescent
Marcescence is the withering and persistence of plant organs that normally are shed, and is a term most commonly applied to plant leaves. The underlying physiological mechanism is that trees transfer water and sap from the roots to the leaves through their vascular cells, but in some trees as autumn begins, the veins carrying the sap slowly close until a layer of cells called the abscission layer completely closes off the vein allowing the tree to rid itself of the leaf. Leaf marcescence is most often seen on juvenile plants and may disappear as the tree matures. It also may not affect the entire tree; sometimes leaves persist only on scattered branches. Marcescence is most obvious in deciduous trees that retain leaves through the winter. Trees that exhibit marcescence are known as "everciduous". Several trees normally have marcescent leaves such as oak (''Quercus''), beech (''Fagus'') and hornbeam (''Carpinus''), or marcescent stipules as in some but not all species of willows ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serrated Leaves
A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, flower, and fruit collectively form the shoot system. In most leaves, the primary photosynthetic tissue is the palisade mesophyll and is located on the upper side of the blade or lamina of the leaf but in some species, including the mature foliage of ''Eucalyptus'', palisade mesophyll is present on both sides and the leaves are said to be isobilateral. Most leaves are flattened and have distinct upper (adaxial) and lower (abaxial) surfaces that differ in color, hairiness, the number of stomata (pores that intake and output gases), the amount and structure of epicuticular wax and other features. Leaves are mostly green in color due to the presence of a compound called chlorophyll that is essential for photosynthesis as it absorbs light ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dentate Leaf
The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular or irregular, may be smooth or bearing hair, bristles or spines. For more terms describing other aspects of leaves besides their overall morphology see the leaf article. The terms listed here all are supported by technical and professional usage, but they cannot be represented as mandatory or undebatable; readers must use their judgement. Authors often use terms arbitrarily, or coin them to taste, possibly in ignorance of established terms, and it is not always clear whether because of ignorance, or personal preference, or because usages change with time or context, or because of variation between specimens, even specimens from the same plant. For example, whether to call leaves on the same tree "acuminate", "lanceolate", or "linear" could ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leaf
A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, flower, and fruit collectively form the shoot system. In most leaves, the primary photosynthetic tissue is the palisade mesophyll and is located on the upper side of the blade or lamina of the leaf but in some species, including the mature foliage of ''Eucalyptus'', palisade mesophyll is present on both sides and the leaves are said to be isobilateral. Most leaves are flattened and have distinct upper (adaxial) and lower ( abaxial) surfaces that differ in color, hairiness, the number of stomata (pores that intake and output gases), the amount and structure of epicuticular wax and other features. Leaves are mostly green in color due to the presence of a compound called chlorophyll that is essential for photosynthesis as it absorbs light ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spiral
In mathematics, a spiral is a curve which emanates from a point, moving farther away as it revolves around the point. Helices Two major definitions of "spiral" in the American Heritage Dictionary are:Spiral ''American Heritage Dictionary of the English Language'', Houghton Mifflin Company, Fourth Edition, 2009. # a curve on a plane that winds around a fixed center point at a continuously increasing or decreasing distance from the point. # a three-dimensional curve that turns around an axis at a constant or continuously varying distance while moving parallel to the axis; a . The first definition describes a |
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