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Single Access Key
In phylogenetics, a single-access key (also called dichotomous key, sequential key, analytical key, or pathway key) is an identification key where the sequence and structure of identification steps is fixed by the author of the key. At each point in the decision process, multiple alternatives are offered, each leading to a result or a further choice. The alternatives are commonly called "leads", and the set of leads at a given point a "couplet". Single access keys are closely related to decision trees or self-balancing binary search trees. However, to improve the usability and reliability of keys, many single-access keys incorporate reticulation, changing the tree structure into a directed acyclic graph. Single-access keys have been in use for several hundred years. They may be printed in various styles (e. g., linked, nested, indented, graphically branching) or used as interactive, computer-aided keys. In the latter case, either a longer part of the key may be displayed (op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenetics
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups of organisms. These relationships are determined by Computational phylogenetics, phylogenetic inference methods that focus on observed heritable traits, such as DNA sequences, protein amino acid sequences, or morphology. The result of such an analysis is a phylogenetic tree—a diagram containing a hypothesis of relationships that reflects the evolutionary history of a group of organisms. The tips of a phylogenetic tree can be living taxa or fossils, and represent the "end" or the present time in an evolutionary lineage. A phylogenetic diagram can be rooted or unrooted. A rooted tree diagram indicates the hypothetical common ancestor of the tree. An unrooted tree diagram (a network) makes no assumption about the ancestral line, and do ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism for the union of sperm with eggs. Flowers may facilitate outcrossing (fusion of sperm and eggs from different individuals in a population) resulting from cross-pollination or allow selfing (fusion of sperm and egg from the same flower) when self-pollination occurs. There are two types of pollination: self-pollination and cross-pollination. Self-pollination occurs when the pollen from the anther is deposited on the stigma of the same flower, or another flower on the same plant. Cross-pollination is when pollen is transferred from the anther of one flower to the stigma of another flower on a different individual of the same species. Self-pollination happens in flowers where the stamen and carpel mature at the same time, and are posi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Oaks
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, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Live Oak
Live oak or evergreen oak is any of a number of oaks in several different sections of the genus ''Quercus'' that share the characteristic of evergreen foliage. These oaks are not more closely related to each other than they are to other oaks. The name ''live oak'' comes from the fact that evergreen oaks remain green and "live" throughout winter, when other oaks are dormant and leafless. The name is used mainly in North America, where evergreen oaks are widespread in warmer areas along the Atlantic coast from southeast Virginia to Florida, west along the Gulf Coast to Louisiana and Mexico, and across the southwest to California. Evergreen oak species are also common in parts of southern Europe and south Asia, and are included in this list for the sake of completeness. These species, although not having "live" in their common names in their countries of origin, are colloquially called live oaks when cultivated in North America. When the term live oak is used in a specific rath ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swamp Chestnut Oak
''Quercus michauxii'', the swamp chestnut oak, is a species of oak in the white oak section ''Quercus'' section ''Quercus'' in the beech family. It is native to bottomlands and wetlands in the southeastern and midwestern United States, in coastal states from New Jersey to Texas, inland primarily in the Mississippi–Ohio Valley as far as Oklahoma, Missouri, Illinois, and Indiana. Description The leaves of the swamp chestnut oak are simple (not compound), long and broad, with 15–20 lobe-like, rounded simple teeth on each side, similar to those of chestnut oak and chinkapin oak (''Quercus muehlenbergii''), although they generally do not achieve the more slender form that the leaves of those trees may exhibit at times. The leaves turn red in autumn. The fruit is an acorn long and broad, borne on a 2–3 cm peduncle, maturing in the fall, about 6 months after pollination. The tree only bears heavy acorn crops at intervals of several years. Taxonomy The swamp chestnu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quercus Alba
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] |
Northern Red Oak
''Quercus rubra'', the northern red oak, is an oak tree in the red oak group (''Quercus'' section ''Lobatae''). It is a native of North America, in the eastern and central United States and southeast and south-central Canada. It has been introduced to small areas in Western Europe, where it can frequently be seen cultivated in gardens and parks. It prefers good soil that is slightly acidic. Often simply called red oak, northern red oak is so named to distinguish it from southern red oak (''Q. falcata''), also known as the Spanish oak. Northern Red Oak is sometimes called champion oak. Description In many forests, this deciduous tree grows straight and tall, to , exceptionally to tall, with a trunk of up to in diameter. Open-grown trees do not get as tall, but can develop a stouter trunk, up to in diameter. It has stout branches growing at right angles to the stem, forming a narrow round-topped head. Under optimal conditions and full sun, northern red oak is fast grow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blackjack Oak
''Quercus marilandica'', the blackjack oak, is a small oak, one of the red oak group ''Quercus'' sect. ''Lobatae''. It is native to the eastern and central United States. Description ''Quercus marilandica'' is a small deciduous tree growing to tall, with bark cracked into rectangular black plates with narrow orange fissures. The leaves are long and broad, and typically flare from a tapered base to a broad three-lobed bell shape with only shallow indentations. They are dark green and glossy above, pubescent underneath, and often remain attached to the twigs through the winter after turning colors from red to brown in the fall. The acorn is small, long and broad; like those of other red oaks, it takes 18 months to mature. Blackjack oaks in the Cross Timbers can grow from high but seldom reach more than , with a trunk diameter of . The leaves are from in length and about the same width. Distribution and habitat The blackjack oak can be found from Long Island to Florida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shingle Oak
''Quercus imbricaria'', the shingle oak, is a deciduous tree in the red oak group of oaks. It is native primarily to the Midwestern and Upper South regions of North America. Description A tree usually 15–18 meters (50–60 feet) high, maximum height 100 ft, with broad pyramidal head when young, becoming in old age broad-topped and open. Trunk up to 1 m (40 inches) in diameter (rarely 1.4 m or 56 in). It reaches its largest size in southern Illinois and Indiana, although the national champion is 104' by 68' in Cincinnati, Ohio. * Bark: Light brown, scaly; on young stems light brown, smooth. Branchlets slender, dark green and shining at first, later become light brown, finally dark brown. * Wood: Pale reddish brown, sapwood lighter; heavy, hard coarse-grained, checks badly in drying; used for shingles and sometimes in construction. Sp. gr., 0.7529; weight of cu. ft., 46.92 lbs. * Winter buds: Light brown, ovate, acute, one-eight inch long. * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Willow Oak
''Quercus phellos'', the willow oak, is a North American species of a deciduous tree in the red oak group of oaks. It is native to the south-central and eastern United States. Description It is a medium-sized tree growing to tall (exceptionally to ), with a trunk up to in diameter (exceptionally ). It is distinguished from most other oaks by its leaves, which are shaped like willow leaves, long and broad with an entire (untoothed and unlobed) margin; they are bright green above, paler beneath, usually hairless but sometimes downy beneath. The fruit is an acorn, long, and almost as wide as long, with a shallow cup; it is one of the most prolific producers of acorns. The tree starts acorn production around 15 years of age, earlier than many oak species. Willow oaks can grow moderately fast (height growth up to a year), and tend to be conic to oblong when young, rounding out and gaining girth at maturity (i.e. more than 50 years). Distribution and habitat The species i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dwarf Live Oak
''Quercus minima'', the dwarf live oak or minimal oak, is a North American species of shrubs in the beech family. It is native to the southeastern United States. ''Quercus minima'' is an evergreen or semi-evergreen shrub rarely more than tall, reproducing by seed and also by means of underground rhizomes. It commonly forms extensive cloned colonies with many stems, many of them unbranched. The leaves are alternate, up to long, and toothless or with irregular teeth or lobes. The lobes, when present, are usually spine-tipped. The leaves are retained through the winter, dropping just before or as new growth resumes in late winter or early spring. ''Quercus minima'' is native to the coastal plain of the southeastern United States, primarily in Florida but extending from there to the Carolinas and eastern Louisiana Louisiana , group=pronunciation (French: ''La Louisiane'') is a state in the Deep South and South Central regions of the United States. It is the 20th-smalle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southern Live Oak
''Quercus virginiana'', also known as the southern live oak, is an evergreen oak tree endemic to the Southeastern United States. Though many other species are loosely called live oak, the southern live oak is particularly iconic of the Old South. Many very large and old specimens of live oak can be found today in the Deep South region of the United States. Description Although live oaks retain their leaves nearly year-round, they are not true evergreens. Live oaks drop their leaves immediately before new leaves emerge in the spring. Occasionally, senescing leaves may turn yellow or contain brown spots in the winter, leading to the mistaken belief that the tree has oak wilt, whose symptoms typically occur in the summer. A live oak's defoliation may occur sooner in marginal climates or in dry or cold winters. The bark is dark, thick, and furrowed longitudinally. The leaves are stiff and leathery, with the tops shiny dark green and the bottoms pale gray and very tightly toment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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