1.
Liriodendron tulipifera
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It is native to eastern North America from Southern Ontario and Illinois eastward to southeastern Massachusetts and Rhode Island, and south to central Florida and Louisiana. It can grow to more than 50 m in virgin forests of the Appalachian Mountains, often with no limbs until it reaches 25–30 m in height. It is fast-growing, without the problems of weak wood strength. April marks the start of the period in the southern USA. The flowers are green or yellow, with an orange band on the tepals. The tulip tree is the tree of Indiana, Kentucky. The tulip tree is one of the largest of the trees of the eastern United States, known to reach the height of 60 m, with a trunk 3 m in diameter. It prefers deep, rich, and rather moist soil, it is common, though not abundant, growth is fairly rapid, and the typical form of its head is conical. The bark is brown, and furrowed, the branchlets are smooth, and lustrous, initially reddish, maturing to dark gray, and finally brown. The wood is yellow to brown, and the sapwood creamy white, light, soft, brittle, close. Specific gravity,0.4230, density,422 g/dm3, winter buds, Dark red, covered with a bloom, obtuse, scales becoming conspicuous stipules for the unfolding leaf, and persistent until the leaf is fully grown. Flower-bud enclosed in a two-valved, caducous bract, the alternate leaves are simple, pinnately veined, measuring five to six inches long and wide. In autumn they turn a clear, bright yellow, perfect, solitary, terminal, greenish yellow, borne on stout peduncles, an inch and a half to two inches long, cup-shaped, erect, conspicuous. The bud is enclosed in a sheath of two bracts which fall as the blossom opens. Calyx, Sepals three, imbricate in bud, reflexed or spreading, somewhat veined, early deciduous, corolla, Cup-shaped, petals six, two inches long, in two rows, imbricate, hypogynous, greenish yellow, marked toward the base with yellow. Stamens, Indefinite, imbricate in many ranks on the base of the receptacle, filaments thread-like, short, anthers extrorse, long, two-celled, adnate, pistils, Indefinite, imbricate on the long slender receptacle. Ovary one-celled, style acuminate, flattened, stigma short, one-sided, recurved, fruit, Narrow light brown cone, formed from many samaras which are dispersed by wind, leaving the axis persistent all winter. A description from Our native trees and how to identify them by Harriet Louise Keeler, The leaves are of unusual shape and develop in a most peculiar, the leaf-buds are composed of scales as is usual, and these scales grow with the growing shoot
2.
Populus tremula
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It also occurs at one site in northwest Africa in Algeria. In the south of its range, it occurs at altitudes in mountains. The English name Waverly, meaning quaking aspen, is both a surname and unisex given name and it is a substantial deciduous tree growing to 40 m tall by 10 m broad, with a trunk attaining over 1 m in diameter. The bark is pale greenish-grey and smooth on young trees with dark grey diamond-shaped lenticels, becoming dark grey and fissured on older trees. The adult leaves, produced on branches of trees, are nearly round, slightly wider than long, 2–8 cm diameter, with a coarsely toothed margin. The leaves on seedlings and fast-growing stems of suckers are of a different shape and they are also often much larger, up to 20 cm long, their petiole is also less flattened. The flowers are wind-pollinated catkins produced in spring before the new leaves appear, they are dioecious. The fluff assists wind dispersal of the seeds when the split open at maturity. It can be distinguished from the closely related North American Populus tremuloides by the leaves being more coarsely toothed, like other aspens, it spreads extensively by suckers, which may be produced up to 40 m from the parent tree, forming extensive clonal colonies. Eurasian aspen is a water and light demanding species that is able to colonize an open area after fire. After an individual has been damaged or destroyed, root suckers are produced abundantly on the lateral roots. Fast growth continues until the age of about 20 years when crown competition increases, after that, growth speed decreases and culminates at about 30 years of age. Aspen can reach an age of 200 years and it is a very hardy species and tolerates long, cold winters and short summers. Aspen is resistant to browsing pressure by fallow deer due to its unpleasant taste, the aspen is found in cultivation in parks and large gardens. The hybrid with Populus alba, known as poplar, Populus × canescens, is widely found in Europe. Hybrids with several other aspens have also bred at forestry research institutes in order to find trees with greater timber production. The wood of aspen is light soft and has very little shrinkage and it is used for lumber and matches but is also valued in the pulp and paper industry, being particular useful for writing paper. In addition, it is used for plywood and different types of flake, furthermore, the tree plays an important role in production of wood for renewable energy
3.
Taxonomy (biology)
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Taxonomy is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. The exact definition of taxonomy varies from source to source, but the core of the remains, the conception, naming. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy, the broadest meaning of taxonomy is used here. The word taxonomy was introduced in 1813 by Candolle, in his Théorie élémentaire de la botanique, the term alpha taxonomy is primarily used today to refer to the discipline of finding, describing, and naming taxa, particularly species. In earlier literature, the term had a different meaning, referring to morphological taxonomy, ideals can, it may be said, never be completely realized. They have, however, a value of acting as permanent stimulants. Some of us please ourselves by thinking we are now groping in a beta taxonomy, turrill thus explicitly excludes from alpha taxonomy various areas of study that he includes within taxonomy as a whole, such as ecology, physiology, genetics, and cytology. He further excludes phylogenetic reconstruction from alpha taxonomy, thus, Ernst Mayr in 1968 defined beta taxonomy as the classification of ranks higher than species. This activity is what the term denotes, it is also referred to as beta taxonomy. How species should be defined in a group of organisms gives rise to practical and theoretical problems that are referred to as the species problem. The scientific work of deciding how to define species has been called microtaxonomy, by extension, macrotaxonomy is the study of groups at higher taxonomic ranks, from subgenus and above only, than species. While some descriptions of taxonomic history attempt to date taxonomy to ancient civilizations, earlier works were primarily descriptive, and focused on plants that were useful in agriculture or medicine. There are a number of stages in scientific thinking. Early taxonomy was based on criteria, the so-called artificial systems. Later came systems based on a complete consideration of the characteristics of taxa, referred to as natural systems, such as those of de Jussieu, de Candolle and Bentham. The publication of Charles Darwins Origin of Species led to new ways of thinking about classification based on evolutionary relationships and this was the concept of phyletic systems, from 1883 onwards. This approach was typified by those of Eichler and Engler, the advent of molecular genetics and statistical methodology allowed the creation of the modern era of phylogenetic systems based on cladistics, rather than morphology alone. Taxonomy has been called the worlds oldest profession, and naming and classifying our surroundings has likely been taking place as long as mankind has been able to communicate
4.
Plant
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Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. The term is generally limited to the green plants, which form an unranked clade Viridiplantae. This includes the plants, conifers and other gymnosperms, ferns, clubmosses, hornworts, liverworts, mosses and the green algae. Green plants have cell walls containing cellulose and obtain most of their energy from sunlight via photosynthesis by primary chloroplasts and their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic and have lost the ability to produce amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although reproduction is also common. There are about 300–315 thousand species of plants, of which the great majority, green plants provide most of the worlds molecular oxygen and are the basis of most of Earths ecologies, especially on land. Plants that produce grains, fruits and vegetables form humankinds basic foodstuffs, Plants play many roles in culture. They are used as ornaments and, until recently and in variety, they have served as the source of most medicines. The scientific study of plants is known as botany, a branch of biology, Plants are one of the two groups into which all living things were traditionally divided, the other is animals. The division goes back at least as far as Aristotle, who distinguished between plants, which generally do not move, and animals, which often are mobile to catch their food. Much later, when Linnaeus created the basis of the system of scientific classification. Since then, it has become clear that the plant kingdom as originally defined included several unrelated groups, however, these organisms are still often considered plants, particularly in popular contexts. When the name Plantae or plant is applied to a group of organisms or taxon. The evolutionary history of plants is not yet settled. Those which have been called plants are in bold, the way in which the groups of green algae are combined and named varies considerably between authors. Algae comprise several different groups of organisms which produce energy through photosynthesis, most conspicuous among the algae are the seaweeds, multicellular algae that may roughly resemble land plants, but are classified among the brown, red and green algae. Each of these groups also includes various microscopic and single-celled organisms
5.
Flowering plant
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The flowering plants, also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants, with 416 families, approx. 13,164 known genera and a total of c.295,383 known species, etymologically, angiosperm means a plant that produces seeds within an enclosure, in other words, a fruiting plant. The term angiosperm comes from the Greek composite word meaning enclosed seeds, the ancestors of flowering plants diverged from gymnosperms in the Triassic Period, during the range 245 to 202 million years ago, and the first flowering plants are known from 160 mya. They diversified extensively during the Lower Cretaceous, became widespread by 120 mya, angiosperms differ from other seed plants in several ways, described in the table. These distinguishing characteristics taken together have made the angiosperms the most diverse and numerous land plants, the amount and complexity of tissue-formation in flowering plants exceeds that of gymnosperms. The vascular bundles of the stem are arranged such that the xylem and phloem form concentric rings, in the dicotyledons, the bundles in the very young stem are arranged in an open ring, separating a central pith from an outer cortex. In each bundle, separating the xylem and phloem, is a layer of meristem or active formative tissue known as cambium, the soft phloem becomes crushed, but the hard wood persists and forms the bulk of the stem and branches of the woody perennial. Among the monocotyledons, the bundles are more numerous in the stem and are scattered through the ground tissue. They contain no cambium and once formed the stem increases in diameter only in exceptional cases, the characteristic feature of angiosperms is the flower. Flowers show remarkable variation in form and elaboration, and provide the most trustworthy external characteristics for establishing relationships among angiosperm species, the function of the flower is to ensure fertilization of the ovule and development of fruit containing seeds. The floral apparatus may arise terminally on a shoot or from the axil of a leaf, occasionally, as in violets, a flower arises singly in the axil of an ordinary foliage-leaf. There are two kinds of cells produced by flowers. Microspores, which divide to become pollen grains, are the male cells and are borne in the stamens. The female cells called megaspores, which divide to become the egg cell, are contained in the ovule. The flower may consist only of parts, as in willow. Usually, other structures are present and serve to protect the sporophylls, the individual members of these surrounding structures are known as sepals and petals. The outer series is usually green and leaf-like, and functions to protect the rest of the flower, the inner series is, in general, white or brightly colored, and is more delicate in structure. It functions to attract insect or bird pollinators, attraction is effected by color, scent, and nectar, which may be secreted in some part of the flower
6.
Eudicots
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The eudicots, Eudicotidae or eudicotyledons are a monophyletic clade of flowering plants that had been called tricolpates or non-magnoliid dicots by previous authors. The close relationships among flowering plants with tricolpate pollen grains was initially seen in studies of shared derived characters. These plants have a trait in their pollen grains of exhibiting three colpi or grooves paralleling the polar axis. Later molecular evidence confirmed the basis for the evolutionary relationships among flowering plants with tricolpate pollen grains. The term means true dicotyledons, as it contains the majority of plants that have been considered dicots and have characteristics of the dicots, the term eudicots has subsequently been widely adopted in botany to refer to one of the two largest clades of angiosperms, monocots being the other. The remaining angiosperms are sometimes referred to as basal angiosperms or paleodicots, the other name for the eudicots is tricolpates, a name which refers to the grooved structure of the pollen. Members of the group have tricolpate pollen, or forms derived from it and these pollens have three or more pores set in furrows called colpi. In contrast, most of the seed plants produce monosulcate pollen. The name tricolpates is preferred by some botanists to avoid confusion with the dicots, numerous familiar plants are eudicots, including many common food plants, trees, and ornamentals. Most leafy trees of midlatitudes also belong to eudicots, with exceptions being magnolias and tulip trees which belong to magnoliids, and Ginkgo biloba. The name eudicots is used in the APG system, of 1998 and it is applied to a clade, a monophyletic group, which includes most of the dicots. The eudicots can be divided into two groups, the basal eudicots and the core eudicots, basal eudicot is an informal name for a paraphyletic group. The core eudicots are a monophyletic group, a 2010 study suggested the core eudicots can be divided into two clades, Gunnerales and a clade called Pentapetalae, comprising all the remaining core eudicots
7.
Rosids
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The rosids are members of a large clade of flowering plants, containing about 70,000 species, more than a quarter of all angiosperms. The clade is divided into 16 to 20 orders, depending upon circumscription and classification and these orders, in turn, together comprise about 140 families. Fossil rosids are known from the Cretaceous period, molecular clock estimates indicate that the rosids originated in the Aptian or Albian stages of the Cretaceous, between 125 and 99.6 million years ago. The name is based upon the name Rosidae, which had usually been understood to be a subclass, in 1967, Armen Takhtajan showed that the correct basis for the name Rosidae is a description of a group of plants published in 1830 by Friedrich Gottlieb Bartling. The clade was later renamed Rosidae and has been variously delimited by different authors, the name rosids is informal and not assumed to have any particular taxonomic rank like the names authorized by the ICBN. The rosids are monophyletic based upon evidence found by molecular phylogenetic analysis, three different definitions of the rosids were used. Some authors included the orders Saxifragales and Vitales in the rosids, others excluded both of these orders. The circumscription used in this article is that of the APG IV classification, which includes Vitales, the rosids and Saxifragales form the superrosids clade. This is one of three groups compose the Pentapetalae, the others being Dilleniales and the superasterids. The rosids consist of two groups, the order Vitales and the eurosids, the eurosids, in turn, are divided into two groups, fabids and malvids. The rosids consist of 17 orders, in addition to Vitales, there are 8 orders in fabids and 8 orders in malvids. Some of the orders have only recently been recognized and these are Vitales, Zygophyllales, Crossosomatales, Picramniales, and Huerteales. The phylogeny of Rosids shown below is adapted from the Angiosperm Phylogeny Group website, the nitrogen-fixing clade contains a high number of actinorhizal plants. Not all plants in this clade are actinorhizal, however, media related to Rosids at Wikimedia Commons
8.
Malpighiales
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The Malpighiales comprise one of the largest orders of flowering plants, containing about 16,000 species, about 7. 8% of the eudicots. The order is very diverse, containing plants as different as the willow, violet, Poinsettia, and coca plant and it is not part of any of the classification systems based only on plant morphology. Molecular clock calculations estimate the origin of stem group Malpighiales at around 100 million years ago, the Malpighiales are divided into 32 to 42 families, depending upon which clades in the order are given the taxonomic rank of family. In the APG III system,35 families are recognized, medusagynaceae, Quiinaceae, Peraceae, Malesherbiaceae, Turneraceae, Samydaceae, and Scyphostegiaceae are consolidated into other families. The largest family, by far, is the Euphorbiaceae, with about 6300 species in about 245 genera, in a 2009 study of DNA sequences of 13 genes,42 families were placed into 16 groups, ranging in size from one to 10 families. Almost nothing is known about the relationships among these 16 groups, Malpighiales and Lamiales are the two large orders whose phylogeny remains mostly unresolved. Malpighiales is a member of a group called the COM clade, which consists of the orders Celastrales, Oxalidales. Some describe it as containing an order, Huales, separating the family Huaceae into its own order. Some recent studies have placed Malpighiales as sister to Oxalidales sensu lato, the COM clade is part of an unranked group known as Fabidae or eurosids I. The fabids, in turn, are part of a group that has long recognized, namely. The family Malpighiaceae was the family for one of the orders created by Jussieu in his 1789 work Genera Plantarum. Friedrich von Berchtold and Jan Presl described such an order in 1820, unlike modern taxonomists, these authors did not use the suffix ales in naming their orders. The name Malpighiales is attributed by some to Carl von Martius, in the 20th century, it was usually associated with John Hutchinson, who used it in all three editions of his book, The Families of Flowering Plants. The name was not used by those who later, in the 1970s, 80s. The taxon was largely presaged by Hans Hallier in 1912 in an article in the Archiv, the first semblance of Malpighiales as now known came from a phylogeny of seed plants published in 1993 and based upon DNA sequences of the gene rbcL. This study recovered a group of rosids unlike any found in any previous system of plant classification. Malpighiales is monophyletic and in phylogenetic studies, it receives strong statistical support. Since the APG II system was published in 2003, minor changes to the circumscription of the order have been made, the family Peridiscaceae has been expanded from two genera to three, and then to four, and transferred to Saxifragales
9.
Salicaceae
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The Salicaceae are a family, the willow family, of flowering plants. The traditional family included the willows, poplar, aspen, recent genetic studies summarized by the Angiosperm Phylogeny Group have greatly expanded the circumscription of the family to contain 56 genera and about 1220 species. In the Cronquist system, the Salicaceae were assigned to their own order, Salicales, the family is placed by the APG in the order Malpighiales. Media related to Salicaceae at Wikimedia Commons Data related to Salicaceae at Wikispecies
10.
Carl Linnaeus
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Carl Linnaeus, also known after his ennoblement as Carl von Linné, was a Swedish botanist, physician, and zoologist, who formalised the modern system of naming organisms called binomial nomenclature. He is known by the father of modern taxonomy. Many of his writings were in Latin, and his name is rendered in Latin as Carolus Linnæus, Linnaeus was born in the countryside of Småland, in southern Sweden. He received most of his education at Uppsala University. He lived abroad between 1735 and 1738, where he studied and also published a first edition of his Systema Naturae in the Netherlands and he then returned to Sweden, where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on journeys through Sweden to find and classify plants. In the 1750s and 1760s, he continued to collect and classify animals, plants, and minerals, at the time of his death, he was one of the most acclaimed scientists in Europe. The philosopher Jean-Jacques Rousseau sent him the message, Tell him I know no man on earth. The German writer Johann Wolfgang von Goethe wrote, With the exception of Shakespeare and Spinoza, Swedish author August Strindberg wrote, Linnaeus was in reality a poet who happened to become a naturalist. Among other compliments, Linnaeus has been called Princeps botanicorum, The Pliny of the North and he is also considered as one of the founders of modern ecology. In botany, the abbreviation used to indicate Linnaeus as the authority for species names is L. In older publications, sometimes the abbreviation Linn. is found, Linnæus was born in the village of Råshult in Småland, Sweden, on 23 May 1707. He was the first child of Nicolaus Ingemarsson and Christina Brodersonia and his siblings were Anna Maria Linnæa, Sofia Juliana Linnæa, Samuel Linnæus, and Emerentia Linnæa. One of a line of peasants and priests, Nils was an amateur botanist, a Lutheran minister. Christina was the daughter of the rector of Stenbrohult, Samuel Brodersonius, a year after Linnæus birth, his grandfather Samuel Brodersonius died, and his father Nils became the rector of Stenbrohult. The family moved into the rectory from the curates house, even in his early years, Linnæus seemed to have a liking for plants, flowers in particular. Whenever he was upset, he was given a flower, which calmed him. Nils spent much time in his garden and often showed flowers to Linnaeus, soon Linnæus was given his own patch of earth where he could grow plants
11.
Type species
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A similar concept is used for suprageneric groups called a type genus. In botanical nomenclature, these terms have no standing under the code of nomenclature. In botany, the type of a name is a specimen which is also the type of a species name. The species name that has that type can also be referred to as the type of the genus name, names of genus and family ranks, the various subdivisions of those ranks, and some higher-rank names based on genus names, have such types. In bacteriology, a species is assigned for each genus. Every named genus or subgenus in zoology, whether or not currently recognized as valid, is associated with a type species. In practice, however, there is a backlog of untypified names defined in older publications when it was not required to specify a type, a type species is both a concept and a practical system that is used in the classification and nomenclature of animals. The type species represents the species and thus definition for a particular genus name. In the Glossary, type species is defined as The nominal species that is the type of a nominal genus or subgenus. The type species permanently attaches a formal name to a genus by providing just one species within that genus to which the name is permanently linked. The species name in turn is fixed, in theory, to a type specimen, for example, the type species for the land snail genus Monacha is Monacha cartusiana. That genus is placed within the family Hygromiidae. The type genus for that family is the genus Hygromia, the concept of the type species in zoology was introduced by Pierre André Latreille. The International Code of Zoological Nomenclature states that the name of the type species should always be cited. It gives an example in Article 67.1, Astacus marinus Fabricius,1775 was later designated as the type species of the genus Homarus, thus giving it the name Homarus marinus. However, the species of Homarus should always be cited using its original name. 3, the type of the genus name Elodes is quoted as the type of the species name Hypericum aegypticum, Glossary of scientific naming Genetypes – genetic sequence data from type specimens. Holotype Paratype Principle of Typification Type Type genus
12.
Species
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In biology, a species is the basic unit of biological classification and a taxonomic rank. A species is defined as the largest group of organisms in which two individuals can produce fertile offspring, typically by sexual reproduction. While this definition is often adequate, looked at more closely it is problematic, for example, with hybridisation, in a species complex of hundreds of similar microspecies, or in a ring species, the boundaries between closely related species become unclear. Other ways of defining species include similarity of DNA, morphology, all species are given a two-part name, a binomial. The first part of a binomial is the genus to which the species belongs, the second part is called the specific name or the specific epithet. For example, Boa constrictor is one of four species of the Boa genus, Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped that species could evolve given sufficient time, Charles Darwins 1859 book The Origin of Species explained how species could arise by natural selection. Genes can sometimes be exchanged between species by horizontal transfer, and species may become extinct for a variety of reasons. In his biology, Aristotle used the term γένος to mean a kind, such as a bird or fish, a kind was distinguished by its attributes, for instance, a bird has feathers, a beak, wings, a hard-shelled egg, and warm blood. A form was distinguished by being shared by all its members, Aristotle believed all kinds and forms to be distinct and unchanging. His approach remained influential until the Renaissance, when observers in the Early Modern period began to develop systems of organization for living things, they placed each kind of animal or plant into a context. Many of these early delineation schemes would now be considered whimsical, animals likewise that differ specifically preserve their distinct species permanently, one species never springs from the seed of another nor vice versa. In the 18th century, the Swedish scientist Carl Linnaeus classified organisms according to shared physical characteristics and he established the idea of a taxonomic hierarchy of classification based upon observable characteristics and intended to reflect natural relationships. At the time, however, it was widely believed that there was no organic connection between species, no matter how similar they appeared. However, whether or not it was supposed to be fixed, by the 19th century, naturalists understood that species could change form over time, and that the history of the planet provided enough time for major changes. Jean-Baptiste Lamarck, in his 1809 Zoological Philosophy, described the transmutation of species, proposing that a species could change over time, in 1859, Charles Darwin and Alfred Russel Wallace provided a compelling account of evolution and the formation of new species. Darwin argued that it was populations that evolved, not individuals and this required a new definition of species. Darwin concluded that species are what appear to be, ideas
13.
Deciduous
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In a more general sense, deciduous means the dropping of a part that is no longer needed or falling away after its purpose is finished. In plants it is the result of natural processes, in botany and horticulture, deciduous plants, including trees, shrubs and herbaceous perennials, are those that lose all of their leaves for part of the year. In some cases leaf loss coincides with winter—namely in temperate or polar climates, in other parts of the world, including tropical, subtropical, and arid regions, plants lose their leaves during the dry season or other seasons, depending on variations in rainfall. The converse of deciduous is coniferous, where foliage is shed on a different schedule from deciduous trees, plants that are intermediate may be called semi-deciduous, they lose old foliage as new growth begins. Other plants are semi-evergreen and lose their leaves before the growing season. Many deciduous plants flower during the period when they are leafless, the absence of leaves improves wind transmission of pollen for wind-pollinated plants and increases the visibility of the flowers to insects in insect-pollinated plants. This strategy is not without risks, as the flowers can be damaged by frost or, in dry season regions, leaf drop or abscission involves complex physiological signals and changes within plants. The process of photosynthesis steadily degrades the supply of chlorophylls in foliage, the brightest leaf colors are produced when days grow short and nights are cool, but remain above freezing. These other pigments include carotenoids that are yellow, brown, anthocyanin pigments produce red and purple colors, though they are not always present in the leaves. Rather, they are produced in the foliage in late summer, parts of the world that have showy displays of bright autumn colors are limited to locations where days become short and nights are cool. In other parts of the world, the leaves of deciduous trees simply fall off without turning the bright colors produced from the accumulation of anthocyanin pigments, the beginnings of leaf drop starts when an abscission layer is formed between the leaf petiole and the stem. This layer is formed in the spring during active new growth of the leaf, the cells are sensitive to a plant hormone called auxin that is produced by the leaf and other parts of the plant. The elongation of cells break the connection between the different cell layers, allowing the leaf to break away from the plant. It also forms a layer that seals the break, so the plant does not lose sap, in the spring, these proteins are used as a nitrogen source during the growth of new leaves or flowers. Plants with deciduous foliage have advantages and disadvantages compared to plants with evergreen foliage, evergreens suffer greater water loss during the winter and they also can experience greater predation pressure, especially when small. Losing leaves in winter may reduce damage from insects, repairing leaves, removing leaves also reduces cavitation which can damage xylem vessels in plants. This then allows deciduous plants to have xylem vessels with larger diameters, the deciduous characteristic has developed repeatedly among woody plants. Trees include maple, many oaks and nothofagus, elm, aspen, Deciduous shrubs include honeysuckle, viburnum, and many others
14.
Northern Hemisphere
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The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined as being in the celestial hemisphere relative to the invariable plane of the solar system as Earths North pole. Due to the Earths axial tilt, winter in the Northern Hemisphere lasts from the December solstice to the March Equinox, the dates vary each year due to the difference between the calendar year and the astronomical year. Its surface is 60. 7% water, compared with 80. 9% water in the case of the Southern Hemisphere, the Arctic is the region north of the Arctic Circle. Its climate is characterized by cold winters and cool summers, precipitation mostly comes in the form of snow. The Arctic experiences some days in summer when the Sun never sets, the duration of these phases varies from one day for locations right on the Arctic Circle to several months near the North Pole, which is the middle of the Northern Hemisphere. Between the Arctic Circle and the Tropic of Cancer lies the Northern Temperate Zone, the changes in these regions between summer and winter are generally mild, rather than extreme hot or cold. However, a temperate climate can have very unpredictable weather, tropical regions are generally hot all year round and tend to experience a rainy season during the summer months, and a dry season during the winter months. In the Northern Hemisphere, objects moving across or above the surface of the Earth tend to turn to the right because of the coriolis effect, as a result, large-scale horizontal flows of air or water tend to form clockwise-turning gyres. These are best seen in circulation patterns in the North Atlantic. For the same reason, flows of air down toward the surface of the Earth tend to spread across the surface in a clockwise pattern. Thus, clockwise air circulation is characteristic of high pressure weather cells in the Northern Hemisphere, conversely, air rising from the northern surface of the Earth tends to draw air toward it in a counterclockwise pattern. Hurricanes and tropical storms spin counter-clockwise in the Northern Hemisphere, the shadow of a sundial moves clockwise in the Northern Hemisphere. When viewed from the Northern Hemisphere, the Moon appears inverted compared to a view from the Southern Hemisphere, the North Pole faces away from the galactic center of the Milky Way. The Northern Hemisphere is home to approximately 6.57 billion people which is around 90% of the total human population of 7.3 billion people
15.
Aspen
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Aspen is a common name for certain tree species, some, but not all, are classified by botanists in the section Populus, of the Populus genus. They are all medium-sized deciduous trees reaching 15–30 m tall, each individual tree can live for 40–150 years above ground, but the root system of the colony is long-lived. In some cases, this is for thousands of years, sending up new trunks as the older trunks die off above ground, for this reason, it is considered to be an indicator of ancient woodlands. One such colony in Utah, given the nickname of Pando, is estimated to be 80,000 years old, some aspen colonies become very large with time, spreading about 1 m per year, eventually covering many hectares. They are able to survive forest fires, because the roots are below the heat of the fire, aspens do not thrive in the shade, and it is difficult for seedlings to grow in an already mature aspen stand. Fire indirectly benefits aspen trees, since it allows the saplings to flourish in open sunlight in the burned landscape, young aspen bark is an important seasonal forage for the European hare and other animals in early spring. Aspen is also a tree of choice of the European beaver, aspen wood is white and soft, but fairly strong, and has low flammability. It has a number of uses, notably for making matches, shredded aspen wood is used for packing and stuffing, sometimes called excelsior. It is also a popular animal bedding, since it lacks the phenols associated with pine and juniper, heat-treated aspen is a popular material for the interiors of a sauna. Trees portal Fox, Mark, Linda E. Tackaberry, Pascal Drouin, Yves Bergeron, Robert L. Bradley, microbial community structure of soils under four productivity classes of aspen forests in Northern British Columbia
16.
Populus sect. Aigeiros
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Populus section Aigeiros is a section of three species in the genus Populus, the poplars. Like some other species in the genus Populus, they are known as cottonwoods. The species are native to North America, Europe, and western Asia, in the past, as many as six species were recognized, but recent trends have been to accept just three species, treating the others as subspecies of P. deltoides. An important feature of the leaves is the petiole, which is flattened sideways so that the leaves have a type of movement in the wind. Male and female flowers are in catkins, appearing before the leaves in spring. The seeds are borne on cottony structures that allow them to be blown long distances in the air before settling to ground, the cottonwoods are exceptionally tolerant of flooding, erosion, and flood deposits filling around the trunk. Although each of the three species has a different leaf pattern, they all have the same general diamond leaf shape. Eastern cottonwood is one of the largest North American hardwood trees and it is a riparian zone tree. It occurs throughout the eastern United States and in extreme southern Canada, the leaves are alternate and simple, with coarsely toothed edges, and subcordate at the base. The leaf shape is triangular, hence the species name. In the typical subspecies P. d. deltoides, the leaves are broad and triangular, further west, the subspecies P. d. monilifera has somewhat narrower leaves, 5–10 cm wide at the base. This is also the tree of Nebraska, Wyoming. In West Texas, New Mexico, and Colorado, the subspecies P. d. wislizeni occurs, fremonts cottonwood is native to the southwestern United States and western Mexico. In the United States, the species can be found in California, Nevada, arizona, New Mexico, Texas and Colorado. In Mexico, it can be found in the states of Baja California, Baja California Sur, Sonora, Chihuahua, Coahuila, Nuevo León, Mexico State, and Puebla. It differs from the eastern cottonwood mainly in the leaves having fewer, larger serrations on the edge, some taxonomists formerly considered P. fremontii to be a subspecies of P. deltoides. Black poplar is native to Europe and Western Asia, is distinct in its smaller leaves, 5–11 centimetres across. Cottonwoods are widely grown for timber production along wet river banks, the wood is coarse and of fairly low value, used for pallet boxes, shipping crates, and similar purposes where a cheap but strong enough wood is suitable
17.
Science (journal)
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Science, also widely referred to as Science Magazine, is the peer-reviewed academic journal of the American Association for the Advancement of Science and one of the worlds top academic journals. It was first published in 1880, is circulated weekly and has a print subscriber base of around 130,000. Because institutional subscriptions and online access serve an audience, its estimated readership is 570,400 people. Unlike most scientific journals, which focus on a field, Science. According to the Journal Citation Reports, Sciences 2015 impact factor was 34.661, although it is the journal of the AAAS, membership in the AAAS is not required to publish in Science. Papers are accepted from authors around the world, competition to publish in Science is very intense, as an article published in such a highly cited journal can lead to attention and career advancement for the authors. Fewer than 7% of articles submitted are accepted for publication, Science is based in Washington, D. C. United States, with an office in Cambridge, England. Science was founded by New York journalist John Michels in 1880 with financial support from Thomas Edison, however, the journal never gained enough subscribers to succeed and ended publication in March 1882. Entomologist Samuel H. Scudder resurrected the journal one year later and had some success while covering the meetings of prominent American scientific societies, however, by 1894, Science was again in financial difficulty and was sold to psychologist James McKeen Cattell for $500. In an agreement worked out by Cattell and AAAS secretary Leland O. Howard, after Cattell died in 1944, the ownership of the journal was transferred to the AAAS. After Cattells death in 1944, the journal lacked a consistent editorial presence until Graham DuShane became editor in 1956. In 1958, under DuShanes leadership, Science absorbed The Scientific Monthly, physicist Philip Abelson, a co-discoverer of neptunium, served as editor from 1962 to 1984. Under Abelson the efficiency of the process was improved and the publication practices were brought up to date. During this time, papers on the Apollo program missions and some of the earliest reports on AIDS were published, biochemist Daniel E. Koshland, Jr. served as editor from 1985 until 1995. From 1995 until 2000, neuroscientist Floyd E. Bloom held that position, biologist Donald Kennedy became the editor of Science in 2000. Biochemist Bruce Alberts took his place in March 2008, geophysicist Marcia McNutt became editor-in-chief in June 2013. During her tenure the family of journals expanded to include Science Robotics and Science Immunology, jeremy M. Berg became editor-in-chief on July 1,2016
18.
Populus trichocarpa
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Populus trichocarpa, the black cottonwood, western balsam-poplar or California poplar, is a deciduous broadleaf tree species native to western North America. It is used for timber, and is notable as an organism in plant biology. Its full genome sequence was published in 2006 and it is the first tree species to be sequenced. It is a tree, growing to a height of 30 metres to 50 metres and a trunk diameter of over 2 metres. It is normally fairly short-lived, but some trees may live for up to 400 years, a cottonwood in Willamette Mission State Park near Salem, Oregon holds the national and world records. Last measured in April,2008 this black cottonwood was found to be standing at 155 ft tall,29 ft around, the bark is grey and covered with lenticels, becoming thick and deeply fissured on old trees. The bark can become hard enough to cause sparks when cut with a chainsaw, the stem is grey in the older parts and light brown in younger parts. The crown is usually conical and quite dense. In large trees the lower branches droop downwards, the wood has a light coloring and a straight grain. The leaves are alternate, elliptic with a crenate margin and an acute tip, the buds are conical, long, narrow and sticky, with a strong balsam scent in spring when they open. Populus trichocarpa has an extensive and aggressive root system, which can invade, sometimes the roots can even damage the foundations of buildings by drying out the soil. Flowering and fruiting Populus trichocarpa is normally dioecious, male and female catkins are borne on separate trees, the species reaches flowering age at about 10 years. Flowers may appear in early March to late May in Washington and Oregon, and sometimes as late as mid-June in northern and interior British Columbia, Idaho, staminate catkins contain 30 to 60 stamens, elongate to 2 to 3 cm, and are deciduous. Pistillate catkins at maturity are 8 to 20 cm long with rotund-ovate, each capsule contains many minute seeds with long, white cottony hairs. Seed production and dissemination The seed ripens and is disseminated by late May to late June in Oregon and Washington, abundant seed crops are usually produced every year. Attached to its cotton, the seed is light and buoyant and can be transported long distances by wind, although highly viable, longevity of P. trichocarpa seed under natural conditions may be as short as two weeks to a month. This can be increased with cold storage, seedling development Moist seedbeds are essential for high germination, and seedling survival depends on continuously favorable conditions during the first month. Wet bottom lands of rivers and major streams frequently provide such conditions, P. trichocarpa seedlings do not usually become established in abundance after logging unless special measures are taken to prepare the bare, moist seedbeds required for initial establishment
19.
DNA sequencing
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DNA sequencing is the process of determining the precise order of nucleotides within a DNA molecule. It includes any method or technology that is used to determine the order of the four bases—adenine, guanine, cytosine, the advent of rapid DNA sequencing methods has greatly accelerated biological and medical research and discovery. The first DNA sequences were obtained in the early 1970s by academic researchers using laborious methods based on two-dimensional chromatography, following the development of fluorescence-based sequencing methods with a DNA sequencer, DNA sequencing has become easier and orders of magnitude faster. DNA sequencing may be used to determine the sequence of genes, larger genetic regions, full chromosomes or entire genomes. DNA sequencing is also the most efficient way to sequence RNA or proteins, in fact, DNA sequencing has become a key technology in many areas of biology and other sciences such as medicine, forensics, or anthropology. Sequencing is used in biology to study genomes and the proteins they encode. Information obtained using sequencing allows researchers to identify changes in genes, associations with diseases and phenotypes, the field of metagenomics involves identification of organisms present in a body of water, sewage, dirt, debris filtered from the air, or swab samples from organisms. Knowing which organisms are present in an environment is critical to research in ecology, epidemiology, microbiology. Sequencing enables researchers to determine which types of microbes may be present in a microbiome, medical technicians may sequence genes from patients to determine if there is risk of genetic diseases. This is a form of testing, though some genetic tests may not involve DNA sequencing. DNA sequencing may be used along with DNA profiling methods for forensic identification, the canonical structure of DNA has four bases, thymine, adenine, cytosine, and guanine. DNA sequencing is the determination of the order of these bases in a molecule of DNA. However, there are other bases that may be present in a molecule. In some viruses, cytosine may be replaced by hydroxy methyl or hydroxy methyl glucose cytosine, in mammalian DNA, variant bases with methyl groups or phosphosulfate may be found. Depending on the technique, a particular modification, e. g. the 5mC common in humans. This situation changed after 1944 as a result of experiments by Oswald Avery, Colin MacLeod. This was the first time that DNA was shown capable of transforming the properties of cells, in 1953, James Watson and Francis Crick put forward their double-helix model of DNA, based on crystallized X-ray structures being studied by Rosalind Franklin. According to the model, DNA is composed of two strands of nucleotides coiled around each other, linked together by bonds and running in opposite directions
20.
Bark (botany)
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Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines, and shrubs, Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the bark and the outer bark. The inner bark, which in older stems is living tissue, the outer bark in older stems includes the dead tissue on the surface of the stems, along with parts of the innermost periderm and all the tissues on the outer side of the periderm. The outer bark on trees which lies external to the last formed periderm is also called the rhytidome, Bark has been used to make cloth, canoes, and ropes and used as a surface for paintings and map making. A number of plants are grown for their attractive or interesting bark colorations. What is commonly called bark includes a number of different tissues, Cork is an external, secondary tissue that is impermeable to water and gases, and is also called the phellem. The cork is produced by the cork cambium which is a layer of active cells which serve as a lateral meristem for the periderm. The cork cambium, which is called the phellogen, is normally only one cell layer thick. The phelloderm, which is not always present in all barks, is a layer of cells formed by, together, the phellem, phellogen and phelloderm constitute the periderm. Cork cell walls contain suberin, a substance which protects the stem against water loss, the invasion of insects into the stem. The cambium tissues, i. e. Phloem is a nutrient-conducting tissue composed of sieve tubes or sieve cells mixed with parenchyma, the cortex is the primary tissue of stems and roots. In stems the cortex is between the layer and the phloem, in roots the inner layer is not phloem. From the outside to the inside of a woody stem. The bark includes through, and is composed of periderm and phloem, as the stem ages and grows, changes occur that transform the surface of the stem into the bark. The epidermis is a layer of cells that cover the plant body, including the stems, leaves, flowers and fruits, in old stems the epidermal layer, cortex, and primary phloem become separated from the inner tissues by thicker formations of cork. Due to the cork layer these cells die because they do not receive water. This dead layer is the rough corky bark that forms around tree trunks, often a secondary covering called the periderm forms on small woody stems and many non woody plants, which is composed of cork, the cork cambium, and the phelloderm
21.
Lenticel
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It functions as a pore, providing a pathway for the direct exchange of gases between the internal tissues and atmosphere through the bark, which is otherwise impermeable to gases. The name lenticel, pronounced with an, derives from its lenticular shape, the shape of lenticels is one of the characteristics used for tree identification. Lenticel formation usually begins beneath stomatal complexes during primary growth preceding the development of the first periderm, lenticels are found as raised circular, oval, or elongated areas on stems and roots. As stems and roots mature lenticel development continues in the new periderm, lenticels are also found in pneumatophorous roots. Lenticels are also present on many fruits, quite noticeably on many apples, “Lenticel breakdown” is a global skin disorder of apples in which lenticels develop dark 1–8 mm diameter pits shortly after processing and packing. It is most common on the variety, particularly the ‘Royal Gala’, and also occurs in ‘Fuji’, ‘Granny Smith’, ‘Golden Delicious’. It is more common in regions, and is thought to be related to relative humidity. The effect can be mitigated by spraying the fruit with lipophilic coatings prior to harvest, lenticels are also present on potato tubers. Raven, Peter H. Ray F. Evert, Susan E. Eichorn
22.
Willow
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Most species are known as willow, but some narrow-leaved shrub species are called osier, and some broader-leaved species are referred to as sallow. Some willows are low-growing or creeping shrubs, for example, the dwarf willow rarely exceeds 6 cm in height, though it spreads widely across the ground. Willows all have abundant watery bark sap, which is charged with salicylic acid, soft, usually pliant, tough wood, slender branches. The roots are remarkable for their toughness, size, and tenacity to life, the leaves are typically elongated, but may also be round to oval, frequently with serrated edges. Most species are deciduous, semievergreen willows with coriaceous leaves are rare, e. g. Salix micans, all the buds are lateral, no absolutely terminal bud is ever formed. The buds are covered by a single scale, usually, the bud scale is fused into a cap-like shape, but in some species it wraps around and the edges overlap. The leaves are simple, feather-veined, and typically linear-lanceolate, usually they are serrate, rounded at base, acute or acuminate. The leaf petioles are short, the often very conspicuous, resembling tiny, round leaves. On some species, however, they are small, inconspicuous, in color, the leaves show a great variety of greens, ranging from yellowish to bluish. Willows are dioecious, with male and female flowers appearing as catkins on separate plants and this scale is square, entire, and very hairy. The anthers are rose-colored in the bud, but orange or purple after the flower opens, they are two-celled, the filaments are threadlike, usually pale brown, and often bald. The ovary is one-celled, the style two-lobed, and the ovules numerous, almost all willows take root very readily from cuttings or where broken branches lie on the ground. The few exceptions include the willow and peachleaf willow. One famous example of such growth from cuttings involves the poet Alexander Pope and this twig was planted and thrived, and legend has it that all of Englands weeping willows are descended from this first one. Willows are often planted on the borders of streams so their interlacing roots may protect the bank against the action of the water, frequently, the roots are much larger than the stem which grows from them. Willows are very cross-compatible, and numerous hybrids occur, both naturally and in cultivation, a well-known ornamental example is the weeping willow, which is a hybrid of Peking willow from China and white willow from Europe. The hybrid cultivar Boydii has gained the Royal Horticultural Societys Award of Garden Merit, Willows are used as food plants by the larvae of some Lepidoptera species, such as the mourning cloak butterfly. Ants, such as ants, are common on willows inhabited by aphids, coming to collect aphid honeydew
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Leaf
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A leaf is an organ of a vascular plant and is the principal lateral appendage of the stem. The leaves and stem together form the shoot, Leaves are collectively referred to as foliage, as in autumn foliage. Although leaves can be seen in different shapes, sizes and textures, typically a leaf is a thin, dorsiventrally flattened organ, borne above ground. Most leaves have distinctive upper surface and lower surface that differ in colour, hairiness, broad, flat leaves with complex venation are known as megaphylls and the species that bear them, the majority, as broad-leaved or megaphyllous plants. In others, such as the clubmosses, with different evolutionary origins, some leaves, such as bulb scales are not above ground, and in many aquatic species the leaves are submerged in water. Succulent plants often have thick juicy leaves, but some leaves are without major photosynthetic function and may be dead at maturity, as in some cataphylls, furthermore, several kinds of leaf-like structures found in vascular plants are not totally homologous with them. Examples include flattened plant stems called phylloclades and cladodes, and flattened leaf stems called phyllodes which differ from both in their structure and origin. Many structures of plants, such as the phyllids of mosses and liverworts and even of some foliose lichens. Leaves are the most important organs of most vascular plants and these are then further processed by chemical synthesis into more complex organic molecules such as cellulose, the basic structural material in plant cell walls. The plant must therefore bring these three together in the leaf for photosynthesis to take place. Once sugar has been synthesized, it needs to be transported to areas of growth such as the plant shoots and roots. Vascular plants transport sucrose in a tissue called the phloem. The phloem and xylem are parallel to each other but the transport of materials is usually in opposite directions. Within the leaf these vascular systems branch to form veins which supply as much as the leaf as possible and they are arranged on the plant so as to expose their surfaces to light as efficiently as possible without shading each other, but there are many exceptions and complications. For instance plants adapted to windy conditions may have pendent leaves, such as in many willows, the flat, or laminar, shape also maximises thermal contact with the surrounding air, promoting cooling. Functionally, in addition to photosynthesis the leaf is the site of transpiration and guttation. Many gymnosperms have thin needle-like or scale-like leaves that can be advantageous in cold climates with frequent snow and these are interpreted as reduced from megaphyllous leaves of their Devonian ancestors. For xerophytes the major constraint is not light flux or intensity, some window plants such as Fenestraria species and some Haworthia species such as Haworthia tesselata and Haworthia truncata are examples of xerophytes. and Bulbine mesembryanthemoides
24.
Petiole (botany)
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In botany, the petiole is the stalk that attaches the leaf blade to the stem. The petiole is the transition between the stem and the leaf blade, outgrowths appearing on each side of the petiole in some species are called stipules. Leaves lacking a petiole are called sessile or epetiolate, the petiole is a stalk that attaches a leaf to the plant stem. In petiolate leaves, the stalk may be long, as in the leaves of celery and rhubarb, short or completely absent. Subpetiolate leaves are petiolate, or have an extremely short petiole. The broomrape family Orobanchaceae is an example of a family in which the leaves are always sessile, in some other plant groups, such as the speedwell genus Veronica, petiolate and sessile leaves may occur in different species. In the grasses the leaves are apetiolate, but the blade may be narrowed at the junction with the leaf sheath to form a pseudopetiole. In plants with leaves, the leaflets are attached to a continuation of the petiole called the rachis. Each leaflet may be attached to the rachis by a stalk called the petiolule. There may be swollen regions at either end of the known as pulvina that are composed of a flexible tissue that allows leaf movement. Pulvina are common in the bean family Fabaceae and the plant family Marantaceae. A pulvinus on a petiolule is called a pulvinulus, in some plants, the petioles are flattened and widened, to become phyllodes or phyllodia, or cladophylls and the true leaves may be reduced or absent. Thus, the comes to serve the functions of the leaf. Phyllodes are common in the genus Acacia, especially the Australian species, in Acacia koa, the phyllodes are leathery and thick, allowing the tree to survive stressful environments. The petiole allows partially submerged hydrophytes to have leaves floating at different depths, in plants such as rhubarb, celery, artichokes and cardoons the petioles are cultivated as edible crops. The petiole of rhubarb grows directly from the rhizome and produces the leaf at its end, botanically it is categorized as a vegetable and culinarily used as a fruit. Petiole is pronounced /ˈpiːtᵻoʊl/ and comes from Latin petiolus, or peciolus little foot, stem, the regular diminutive pediculus is also used for foot stalk
25.
Flower
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A flower, sometimes known as a bloom or blossom, is the reproductive structure found in plants that are floral. The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs, Flowers may facilitate outcrossing or allow selfing. Some flowers produce diaspores without fertilization, Flowers contain sporangia and are the site where gametophytes develop. Many flowers have evolved to be attractive to animals, so as to them to be vectors for the transfer of pollen. After fertilization, the ovary of the flower develops into fruit containing seeds, the essential parts of a flower can be considered in two parts, the vegetative part, consisting of petals and associated structures in the perianth, and the reproductive or sexual parts. A stereotypical flower consists of four kinds of structures attached to the tip of a short stalk, each of these kinds of parts is arranged in a whorl on the receptacle. The four main whorls are as follows, Collectively the calyx, corolla, the next whorl toward the apex, composed of units called petals, which are typically thin, soft and colored to attract animals that help the process of pollination. Androecium, the whorl, consisting of units called stamens. Stamens consist of two parts, a called a filament, topped by an anther where pollen is produced by meiosis. Gynoecium, the innermost whorl of a flower, consisting of one or more units called carpels, the carpel or multiple fused carpels form a hollow structure called an ovary, which produces ovules internally. Ovules are megasporangia and they in turn produce megaspores by meiosis which develop into female gametophytes and these give rise to egg cells. The gynoecium of a flower is described using an alternative terminology wherein the structure one sees in the innermost whorl is called a pistil. A pistil may consist of a carpel or a number of carpels fused together. 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. The relationship to the gynoecium on the receptacle is described as hypogynous, perigynous, although the arrangement described above is considered typical, plant species show a wide variation in floral structure. These modifications have significance in the evolution of flowering plants and are used extensively by botanists to establish relationships among plant species, the four main parts of a flower are generally defined by their positions on the receptacle and not by their function. Many flowers lack some parts or parts may be modified into other functions and/or look like what is typically another part, in some families, like Ranunculaceae, the petals are greatly reduced and in many species the sepals are colorful and petal-like. Other flowers have modified stamens that are petal-like, the flowers of Peonies and Roses are mostly petaloid stamens
26.
Plant reproductive morphology
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Plant reproductive morphology is the study of the physical form and structure of those parts of plants directly or indirectly concerned with sexual reproduction. Among all living organisms, flowers, which are the structures of angiosperms, are the most varied physically. Plants that are not flowering plants also have complex interplays between morphological adaptation and environmental factors in their sexual reproduction, christian Konrad Sprengel studied the reproduction of flowering plants and for the first time it was understood that the pollination process involved both biotic and abiotic interactions. Charles Darwins theories of natural selection utilized this work to build his theory of evolution, Plants have complex lifecycles involving alternation of generations. One generation, the sporophyte, gives rise to the next generation asexually via spores, spores may be identical isospores or come in different sizes, but strictly speaking, spores and sporophytes are neither male nor female because they do not produce gametes. The alternate generation, the gametophyte, produces gametes, eggs and/or sperm, a gametophyte can be be monoicous, producing both eggs and sperm or dioicous, either female or male. In the bryophytes, the gametophyte is the dominant generation. In ferns and seed plants the sporophyte is the dominant generation, the obvious visible plant, whether a small herb or a large tree, is the sporophyte, and the gametophyte is very small. In seed plants, each female gametophyte, and the spore that gives rise to it, is hidden within the sporophyte and is dependent on it for nutrition. Each male gametophyte consists of from two to four cells enclosed within the protective wall of a pollen grain. The sporophyte of a plant is often described using sexual terms based on the sexuality of the gametophyte it gives rise to. For example, a sporophyte that produces spores that give rise only to male gametophytes may be described as male, even though the sporophyte itself is asexual, producing only spores. Similarly, flowers produced by the sporophyte may be described as unisexual or bisexual, the flower is the characteristic structure concerned with sexual reproduction in flowering plants. Flowers vary enormously in their construction, a complete flower, like that of Ranunculus glaberrimus shown in the figure, has a calyx of outer sepals and a corolla of inner petals. The sepals and petals form the perianth. Next inwards there are numerous stamens, which produce pollen grains, stamens may be called the male parts of a flower and collectively form the androecium. Finally in the middle there are carpels, which at maturity one or more ovules. Carpels may be called the parts of a flower and collectively form the gynoecium
27.
Catkin
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A catkin or ament is a slim, cylindrical flower cluster, with inconspicuous or no petals, usually wind-pollinated but sometimes insect-pollinated. They contain many, usually flowers, arranged closely along a central stem which is often drooping. They are found in plant families, including Betulaceae, Fagaceae, Moraceae. For some time, they were believed to be a key synapomorphy among the proposed Hamamelididae, based on molecular phylogeny work, it is now believed that Hamamelididae is a polyphyletic group. This suggests that the flower arrangement has arisen at least twice independently by convergent evolution, in Fagales. Such a convergent evolution raises questions about what the ancestral inflorescence characters might be, in many of these plants, only the male flowers form catkins, and the female flowers are single, a cone or other types. In other plants both male and female flowers are borne in catkins, catkin-bearing plants include many other trees or shrubs such as birch, willow, hickory, sweet chestnut and sweetfern. The word catkin is a loanword from the old Dutch katteken, meaning kitten, ament is from the Latin amentum, meaning thong or strap. Catkins in Fagales Catkins in Salicaceae
28.
Sepal
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A sepal is a part of the flower of angiosperms. Usually green, sepals typically function as protection for the flower in bud, the term sepalum was coined by Noël Martin Joseph de Necker in 1790, and derived from the Greek σκεπη, a covering. Collectively the sepals are called the calyx, the outermost whorl of parts that form a flower, the word calyx was adopted from the Latin calyx, not to be confused with calix, a cup or goblet. Calyx derived from the Greek κάλυξ, a bud, a calyx, a husk or wrapping, while derived from the Greek κυλιξ, a cup or goblet. After flowering, most plants have no use for the calyx which withers or becomes vestigial. Some plants retain a thorny calyx, either dried or live, examples include species of Acaena, some of the Solanaceae, and the water caltrop, Trapa natans. In some species the calyx not only persists after flowering, but instead of withering and this is an effective protection against some kinds of birds and insects, for example in Hibiscus trionum and the Cape gooseberry. Morphologically, both sepals and petals are modified leaves, the calyx and the corolla are the outer sterile whorls of the flower, which together form what is known as the perianth. The term tepal is usually applied when the parts of the perianth are difficult to distinguish, e. g. the petals and sepals share the same color, or the petals are absent and the sepals are colorful. When the undifferentiated tepals resemble petals, they are referred to as petaloid, as in petaloid monocots, since they include Liliales, an alternative name is lilioid monocots. Examples of plants in which the term tepal is appropriate include genera such as Aloe, in contrast, genera such as Rosa and Phaseolus have well-distinguished sepals and petals. The number of sepals in a flower is its merosity, flower merosity is indicative of a plants classification. The merosity of a flower is typically four or five. The merosity of a monocot or palaeodicot flower is three, or a multiple of three, the development and form of the sepals vary considerably among flowering plants. They may be free or fused together, often, the sepals are much reduced, appearing somewhat awn-like, or as scales, teeth, or ridges. Most often such structures protrude until the fruit is mature and falls off, examples of flowers with much reduced perianths are found among the grasses. In some flowers, the sepals are fused towards the base, in other flowers a hypanthium includes the bases of sepals, petals, and the attachment points of the stamens
29.
Petal
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Petals are modified leaves that surround the reproductive parts of flowers. They are often brightly colored or unusually shaped to attract pollinators, together, all of the petals of a flower are called a corolla. Petals are usually accompanied by another set of special leaves called sepals, the calyx and the corolla together make up the perianth. When the petals and sepals of a flower are difficult to distinguish, examples of plants in which the term tepal is appropriate include genera such as Aloe and Tulipa. Conversely, genera such as Rosa and Phaseolus have well-distinguished sepals and petals, when the undifferentiated tepals resemble petals, they are referred to as petaloid, as in petaloid monocots, orders of monocots with brightly coloured tepals. Since they include Liliales, a name is lilioid monocots. Although petals are usually the most conspicuous parts of animal-pollinated flowers, wind-pollinated species, such as the grasses, the role of the corolla in plant evolution has been studied extensively since Charles Darwin postulated a theory of the origin of elongated corollae and corolla tubes. If the petals are free from one another in the corolla, the corolla in some plants forms a tube. Petals can differ dramatically in different species, the number of petals in a flower may hold clues to a plants classification. For example, flowers on eudicots most frequently have four or five petals while flowers on monocots have three or six petals, although there are exceptions to this rule. The petal whorl or corolla may be radially or bilaterally symmetrical. If all of the petals are essentially identical in size and shape, many flowers are symmetrical in only one plane and are termed irregular or zygomorphic. In irregular flowers, other parts may be modified from the regular form. Examples of zygomorphic flowers may be seen in orchids and members of the pea family, in many plants of the aster family such as the sunflower, Helianthus annuus, the circumference of the flower head is composed of ray florets. Each ray floret is anatomically an individual flower with a large petal. Florets in the centre of the disc typically have no or very reduced petals, in some plants such as Narcissus the lower part of the petals or tepals are fused to form a floral cup above the ovary, and from which the petals proper extend. Petal often consists of two parts, the upper, broad part, similar to leaf blade, called the limb, claws are developed in petals of some flowers of the family Brassicaceae, such as Erysimum cheiri. The inception and further development of shows a great variety of patterns
30.
Stamen
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The stamen is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium, a stamen typically consists of a stalk called the filament and an anther which contains microsporangia. Most commonly anthers are two-lobed and are attached to the filament either at the base or in the area of the anther. The sterile tissue between the lobes is called the connective, a pollen grain develops from a microspore in the microsporangium and contains the male gametophyte. The stamens in a flower are called the androecium. The androecium can consist of as few a one-half stamen as in Canna species or as many as 3,482 stamens which have been counted in Carnegiea gigantea, the androecium in various species of plants forms a great variety of patterns, some of them highly complex. It surrounds the gynoecium and is surrounded by the perianth, a few members of the family Triuridaceae, particularly Lacandonia schismatica, are exceptional in that their gynoecia surround their androecia. Stamen is the Latin word meaning thread, depending on the species of plant, some or all of the stamens in a flower may be attached to the petals or to the floral axis. They also may be free-standing or fused to one another in different ways, including fusion of some. The filaments may be fused and the free, or the filaments free. Rather than there being two locules, one locule of a stamen may fail to develop, or alternatively the two locules may merge late in development to give a single locule, a typical anther contains four microsporangia. The microsporangia form sacs or pockets in the anther, the two separate locules on each side of an anther may fuse into a single locule. Each microsporangium is lined with a tissue layer called the tapetum. These undergo meiosis to form haploid spores, the spores may remain attached to each other in a tetrad or separate after meiosis. Each microspore then divides mitotically to form an immature microgametophyte called a pollen grain, the pollen is eventually released when the anther forms openings. These may consist of longitudinal slits, pores, as in the family, or by valves. More commonly, mature pollen grains separate and are dispensed by wind or water, pollinating insects, pollen of angiosperms must be transported to the stigma, the receptive surface of the carpel, of a compatible flower, for successful pollination to occur. After arriving, the pollen grain typically completes its development and it may grow a pollen tube and undergoing mitosis to produce two sperm nuclei
31.
Fruit
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In botany, a fruit is the seed-bearing structure in flowering plants formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate seeds, accordingly, fruits account for a substantial fraction of the worlds agricultural output, and some have acquired extensive cultural and symbolic meanings. On the other hand, in usage, fruit includes many structures that are not commonly called fruits, such as bean pods, corn kernels, tomatoes. The section of a fungus that produces spores is called a fruiting body. Many common terms for seeds and fruit do not correspond to the botanical classifications, however, in botany, a fruit is the ripened ovary or carpel that contains seeds, a nut is a type of fruit and not a seed, and a seed is a ripened ovule. Examples of culinary vegetables and nuts that are botanically fruit include corn, cucurbits, eggplant, legumes, sweet pepper, in addition, some spices, such as allspice and chili pepper, are fruits, botanically speaking. g. Botanically, a grain, such as corn, rice, or wheat, is also a kind of fruit. However, the wall is very thin and is fused to the seed coat. The outer, often edible layer, is the pericarp, formed from the ovary and surrounding the seeds, the pericarp may be described in three layers from outer to inner, the epicarp, mesocarp and endocarp. Fruit that bears a prominent pointed terminal projection is said to be beaked, a fruit results from maturation of one or more flowers, and the gynoecium of the flower forms all or part of the fruit. Inside the ovary/ovaries are one or more ovules where the megagametophyte contains the egg cell, after double fertilization, these ovules will become seeds. The ovules are fertilized in a process starts with pollination. After pollination, a tube grows from the pollen through the stigma into the ovary to the ovule, later the zygote will give rise to the embryo of the seed, and the endosperm mother cell will give rise to endosperm, a nutritive tissue used by the embryo. As the ovules develop into seeds, the ovary begins to ripen and the ovary wall, in some multiseeded fruits, the extent to which the flesh develops is proportional to the number of fertilized ovules. The pericarp is often differentiated into two or three distinct layers called the exocarp, mesocarp, and endocarp, in some fruits, especially simple fruits derived from an inferior ovary, other parts of the flower, fuse with the ovary and ripen with it. In other cases, the sepals, petals and/or stamens and style of the fall off. When such other floral parts are a significant part of the fruit, it is called an accessory fruit, since other parts of the flower may contribute to the structure of the fruit, it is important to study flower structure to understand how a particular fruit forms. There are three modes of fruit development, Apocarpous fruits develop from a single flower having one or more separate carpels
32.
Dehiscence (botany)
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Dehiscence is the splitting at maturity along a built-in line of weakness in a plant structure in order to release its contents, and is common among fruits, anthers and sporangia. Sometimes this involves the complete detachment of a part, structures that open in this way are said to be dehiscent. Structures that do not open in this way are called indehiscent, dehiscence may or may not involve the loss of a structure through the process of abscission. The lost structures are said to be caducous, manipulation of dehiscence can improve crop yield since a trait that causes seed dispersal is a disadvantage for farmers whose goal is to collect the seed. Many of the agronomically important plants have been bred for reduced shattering, explosive dehiscence is a ballistic form of dispersal that flings seeds or spores far from the parent plant. This rapid plant movement can achieve limited dispersal without the assistance of animals, a notable example is the sandbox tree, which can fling seeds 100 meters and has been called the Dynamite tree due to the loud sound of its explosive dehiscence. Another example is Impatiens, whose explosive dehiscence is triggered by being touched, explosive dehiscence of sporangia is a characteristic of Sphagnum. Septicidal and loculicidal dehiscence may not be distinct, in some cases both the septa and the walls of the locules split. Dehiscence occurs through breakage of parts of the enclosing structure, the mechanisms can be classified in various ways. Dehiscence through a hole is referred to as poricidal dehiscence. The pore may have a cover that is referred to as an operculum or it may not, poricidal dehiscence occurs in many unrelated organisms, in fruit, causing the release of seeds, and also in the sporangia of many organisms. Poricidal anthers of flowers are associated with buzz pollination by insects. Circumscissile dehiscence involves a horizontal opening that causes a lid to separate completely and this type of dehiscence occurs in some fruit and anthers and also in some flower buds. Anther dehiscence is the function of the anther that causes the release of pollen grains. This process is coordinated precisely with pollen differentiation, floral development, the anther wall breaks at a specific site. Usually this site is observed as an indentation between the locules of each theca and runs the length of the anther, but in species with poricidal anther dehiscence it is instead a small pore. If the pollen is released from the anther through a split on the side, this is extrorse dehiscence, and if the pollen is released from the inner side. If the pollen is released through a split that is positioned to the side, towards other anthers, rather than towards the inside or outside of the flower, the stomium is the region of the anther where dehiscence occurs
33.
Capsule (fruit)
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In botany a capsule is a type of simple, dry rarely fleshy, dehiscent fruit produced by many species of Angiosperms. The capsule is derived from a compound ovary, a capsule is a structure composed of two or more carpels. In, the term locule is used to refer to a chamber within the fruit, depending on the number of locules in the ovary, fruit can be classified as uni-locular, bi-locular, tri-locular or multi-locular. The number of locules present in a gynoecium may be equal to or less than the number of carpels, the locules contain the ovules or seeds and are separated by septa. In most cases the capsule is dehiscent, i. e. at maturity, a few capsules are indehiscent, for example those of Adansonia digitata, Alphitonia, and Merciera. Capsules are often classified into four types, depending on the type, loculicidal capsules possess longitudinal lines of dehiscence radially aligned with the locules, i. e. not at the septa, along the midrib or dorsal suture of the locules. If septa are absent, the dehiscence lines lie between the placentae and this type is common among many members of the Liliaceae such as Lilium. Septicidal capsules have dehiscence lines aligned with the sutures of the ovary septa or placentae, both loculocidal and septicidal capsules split into distinguishable segments called valves. The valves are a part of the pericarp that has split away, the borders of the valves may or may not coincide with the borders of carpels. These valves may remain attached to the fruit or fall off, in septicidal capsules the valves remain in place. In some capsules, the split occurs between carpels, and in each carpel splits open. Circumscissile capsules have a transverse, rather than longitudinal, dehiscence line, so that the part of the capsule dehisces. A variant is the Septifragal capsule in which the outer walls break away from the septa, poricidal capsules dehisce through pores in the capsule, as in Papaver, the seeds escaping through these pores. Examples of other plants that produce capsules include nigella, orchid, willow, cotton, some dry dehiscent fruits form specialised capsule-like strucures. A follicle is derived from a carpel that splits along a suture, as in Magnolia. Some variants of legumes that have retained vestigial sutures include loments that split transversly into segments, each with a single seed, and indehiscent legumes, such as Arachis hypogaea. Capsules derived from two carpels include silicles and siliques that dehisce along two lines but retain a partition called the replum, which is a septum with attached seeds. While both are characteristic of Brassicaceae, silicles is at least as broad as it is long, and vice a versa
34.
Seed
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A seed is an embryonic plant enclosed in a protective outer covering. The formation of the seed is part of the process of reproduction in seed plants, Seeds are the product of the ripened ovule, after fertilization by pollen and some growth within the mother plant. The embryo is developed from the zygote and the coat from the integuments of the ovule. Seed plants now dominate biological niches on land, from forests to both in hot and cold climates. The term seed also has a meaning that antedates the above—anything that can be sown, e. g. seed potatoes. In the case of sunflower and corn seeds, what is sown is the seed enclosed in a shell or husk, many structures commonly referred to as seeds are actually dry fruits. Plants producing berries are called baccate, sunflower seeds are sometimes sold commercially while still enclosed within the hard wall of the fruit, which must be split open to reach the seed. Different groups of plants have other modifications, the stone fruits have a hardened fruit layer fused to. Nuts are the one-seeded, hard-shelled fruit of plants with an indehiscent seed. Seeds are produced in several related groups of plants, and their manner of production distinguishes the angiosperms from the gymnosperms, angiosperm seeds are produced in a hard or fleshy structure called a fruit that encloses the seeds, hence the name. Some fruits have layers of hard and fleshy material. In gymnosperms, no special structure develops to enclose the seeds, however, the seeds do become covered by the cone scales as they develop in some species of conifer. Seed production in natural plant populations varies widely from year-to-year in response to weather variables, insects and diseases, over a 20-year period, for example, forests composed of loblolly pine and shortleaf pine produced from 0 to nearly 5 million sound pine seeds per hectare. Over this period, there were six bumper, five poor, and nine good seed crops, right after fertilization, the zygote is mostly inactive, but the primary endosperm divides rapidly to form the endosperm tissue. This tissue becomes the food the young plant will consume until the roots have developed after germination, after fertilization the ovules develop into the seeds. The ovule consists of a number of components, The funicle or seed stalk which attaches the ovule to the placenta and hence ovary or fruit wall, the nucellus, the remnant of the megasporangium and main region of the ovule where the megagametophyte develops. The micropyle, a pore or opening in the apex of the integument of the ovule where the pollen tube usually enters during the process of fertilization. The chalaza, the base of the ovule opposite the micropyle, the shape of the ovules as they develop often affects the final shape of the seeds
35.
Riparian zone
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A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the fifteen terrestrial biomes of the earth, Plant habitats and communities along the river margins and banks are called riparian vegetation, characterized by hydrophilic plants. In some regions the terms riparian woodland, riparian forest, riparian buffer zone, the word riparian is derived from Latin ripa, meaning river bank. Riparian zones may be natural or engineered for soil stabilization or restoration and these zones are important natural biofilters, protecting aquatic environments from excessive sedimentation, polluted surface runoff and erosion. They supply shelter and food for aquatic animals and shade that limits stream temperature change. When riparian zones are damaged by construction, agriculture or silviculture, biological restoration can take place, usually by human intervention in erosion control and revegetation. If the area adjacent to a watercourse has standing water or saturated soil for as long as a season, because of their prominent role in supporting a diversity of species, riparian zones are often the subject of national protection in a Biodiversity Action Plan. These are also known as a Plant or Vegetation Waste Buffer, research shows that riparian zones are instrumental in water quality improvement for both surface runoff and water flowing into streams through subsurface or groundwater flow. Particularly, the attenuation of nitrate or denitrification of the nitrates from fertilizer in this zone is important. The use of wetland riparian zones shows a high rate of removal of nitrate entering a stream. The meandering curves of a river, combined with vegetation and root systems, slow the flow of water, sediment is trapped, reducing suspended solids to create less turbid water, replenish soils, and build stream banks. Pollutants are filtered from surface runoff, enhancing water quality via biofiltration, the riparian zones also provide wildlife habitat, increased biodiversity, and wildlife corridors, enabling aquatic and riparian organisms to move along river systems avoiding isolated communities. Riparian vegetation can also forage for wildlife and livestock. They provide native landscape irrigation by extending seasonal or perennial flows of water, nutrients from terrestrial vegetation are transferred to aquatic food webs. The vegetation surrounding the stream helps to shade the water, mitigating water temperature changes, the vegetation also contributes wood debris to streams, which is important to maintaining geomorphology. From a social aspect, riparian zones contribute to nearby property values through amenity and views, space is created for riparian sports such as fishing, swimming and launching for vessels and paddlecraft. The protection of zones is often a consideration in logging operations. The undisturbed soil, soil cover, and vegetation provide shade, plant litter, and woody material, factors such as soil types and root structures, climatic conditions and vegetative cover determine the effectiveness of riparian buffering
36.
Larva
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A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a phase of their life cycle. The larvas appearance is very different from the adult form. A larva often has unique structures and organs that do not occur in the adult form and their diet may also be considerably different. Larvae are frequently adapted to separate from adults. For example, some such as tadpoles live almost exclusively in aquatic environments. By living in an environment, larvae may be given shelter from predators. Animals in the stage will consume food to fuel their transition into the adult form. In some species like barnacles, adults are immobile but their larvae are mobile, some larvae are dependent on adults to feed them. In many eusocial Hymenoptera species, the larvae are fed by female workers, in Ropalidia marginata the males are also capable of feeding larvae but they are much less efficient, spending more time and getting less food to the larvae. The larvae of species can become pubescent and do not develop further into the adult form. This is a type of neoteny and it is a misunderstanding that the larval form always reflects the groups evolutionary history. This could be the case, but often the stage has evolved secondarily. In these cases the form may differ more than the adult form from the groups common origin. Within Insects, only Endopterygotes show different types of larvae, several classifications have been suggested by many entomologists, and following classification is based on Antonio Berlese classification in 1913. There are four types of endopterygote larvae types, Apodous larvae - no legs at all and are poorly sclerotized. Based on sclerotization, three forms are recognized. Eucephalous - with well sclerotized head capsule, found in Nematocera, Buprestidae and Cerambycidae families
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Lepidoptera
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The Lepidoptera is an order of insects that includes moths and butterflies. 180,000 species of Lepidoptera are described, in 126 families and 46 superfamilies and it is one of the most widespread and widely recognizable insect orders in the world. The term was coined by Linnaeus in 1735 and is derived from Ancient Greek λεπίδος, the Lepidoptera show many variations of the basic body structure that have evolved to gain advantages in lifestyle and distribution. Recent estimates suggest the order may have more species than earlier thought, and is among the four most speciose orders, along with the Hymenoptera, Diptera, and Coleoptera. Lepidopteran species are characterized by more than three derived features, some of the most apparent being the scales covering their bodies and wings, the scales are modified, flattened hairs, and give butterflies and moths their extraordinary variety of colors and patterns. Almost all species have some form of wings, except for a few that have reduced wings or are wingless. Like most other insects, butterflies and moths are holometabolous, meaning they undergo complete metamorphosis, mating and the laying of eggs are carried out by adults, normally near or on host plants for the larvae. As they grow, these change in appearance, going through a series of stages called instars. Once fully matured, the larva develops into a pupa A few butterflies and many species spin a silk case or cocoon prior to pupating, while others do not. A butterfly pupa, called a chrysalis, has a hard skin, once the pupa has completed its metamorphosis, a sexually mature adult emerges. Accordingly, this is the most recognized and popular of insect orders with many involved in the observation, study, collection, rearing of. A person who collects or studies this order is referred to as a lepidopterist, in many species, the female may produce from 200 to 600 eggs, while in others, the number may approach 30,000 eggs in one day. The caterpillars hatching from eggs can cause damage to large quantities of crops. Many moth and butterfly species are of economic interest by virtue of their role as pollinators, the word Lepidoptera comes from the Latin word for scaly wing, from the Ancient Greek λεπίς meaning scale and πτερόν meaning wing. The origins of the common names butterfly and moth are varied, the English word butterfly is from Old English buttorfleoge, with many variations in spelling. Other than that, the origin is unknown, although it could be derived from the yellow color of many species wings suggesting the color of butter. The species of Heterocera are commonly called moths, the origins of the English word moth are more clear, deriving from the Old English moððe from Common Germanic. The Lepidoptera are among the most successful groups of insects, among the most northern dwelling species of butterflies and moths is the Arctic Apollo, which is found in the Arctic Circle in northeastern Yakutia, at an altitude of 1500 m above sea level
38.
Pleurotus populinus
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Pleurotus populinus, the aspen oyster mushroom, is a gilled fungus native to North America. It is found on wood of aspen and cottonwood trees. Although morphologically similar to Pleurotus ostreatus and Pleurotus pulmonarius, it has shown to be a distinct species incapable of cross-breeding. P. populinus is reported to be edible, unlike P. ostreatus, which fruits in the autumn and winter, P. populinus fruits in late spring and summer. The species was first described scientifically by mycologists Oswald and Orson K. Miller in 1993 with a provisional name and this original naming was invalid according to several sections of the International Code of Botanical Nomenclature, so it was republished in 1997. The fruit bodies have oyster shell-shaped to fan-shaped caps that are 4–19 cm broad by 4–13 cm wide, the cap margin is initially rolled inward, becomes finely scalloped in age. The color ranges from white to pinkish buff to orange-grey. The gills are decurrent, running a short ways down the stipe. They are 3–10 mm broad, white to cream in color, spores are thin-walled with a narrowly elliptical to oblong shape, and dimensions of 9–15 by 3–5 µm. The basidia are club-shaped, four-spored, and measure 20–27 by 5–6 µm, Pleurotus populinus fruit bodies grow singly to numerous—often arranged in overlapping clusters—on the rotting stumps, logs, and limbs of hardwoods. Preferred substrates include aspen and black cottonwood and it is found in the northern United States and Canada, and in mountainous regions of western North America. It is a species in its range, where it fruits in June. List of Pleurotus species Pleurotus populinus in Index Fungorum Pleurotus populinus, The Aspen Oyster at MushroomExpert. com Biological Species in Pleurotus, Pleurotus populinus at University of Tennessee-Knoxville Mycology Lab
39.
Forest dieback
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Forest dieback is a condition in trees or woody plants in which peripheral parts are killed, either by pathogens, parasites or due to conditions like acid rain and drought. Two of the nine tipping points for major changes, forecast for the next century, are directly related to forest diebacks. Phomopsis azadirachtae is a fungus of the Phomopsis genus that has identified as the fungus responsible for dieback of Azadirachta indica in India. Forest dieback refers to the phenomena of a stand of trees losing health and this condition is also known as forest decline, forest damage, canopy level dieback, and stand level dieback. This usually affects individual species of trees, but can affect multiple species. Trees and woody plants are killed by a group of factors that include parasites, such as fungus and beetles, pollution, such as acid rain and organic compounds. Diseases and pests can kill large groups of very easily. Dieback takes on many locations and shapes and it can be along the perimeter, at specific elevations, or dispersed throughout the forest ecosystem. Forest dieback has many dynamic forms, a stand of trees can exhibit mild symptoms, extreme systems, or death at the same time. Forest decline can be viewed as the result of continued, widespread, current forest decline is described by rapid development on individual trees, occurrence in different forest types, a long duration, and occurrence throughout the natural range of affected species. Much research was done in the 1980s when a severe dieback happened in Germany, previous diebacks were regionally limited, but starting at the end of the 1970s a decline took over the forests of Central Europe and parts of North America. The forest damage in Germany was different because the decline was severe, up to 50% of the trees, prolonged, over 5 years, affected trees went from 8% in 1982 to 50% in 1984 and stayed at 50% through 1987. Many hypotheses have proposed for this dieback, see below. Drought and temperature have been factors in many diebacks. This condition is common in regions and the trees are already stressed by dehydration. There have been reported diebacks in the 50% mortality range across multiple species in Africa, Asia, Europe, North America, South and Central America, notable drought related diebacks have occurred globally from the 1970s through the 2000s. A few drought related diebacks have occurred before this, for instance, a 23% mortality rate was reported between 1945 and 1993 in Senegal Africa. Trees stressed by drought and temperature are more susceptible to parasites, in North America there were five notable hardwood diebacks in the XX century
40.
Hornet moth
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The hornet moth or hornet clearwing is a large bulky moth. Adults resemble a large hornet - the wingspan is 33–48 mm. the abdomen has yellow banding, after emergence, most of the wing scales are lost revealing the transparent wing membrane. The hornet moth is a Batesian mimic of, and may be confused with, the moth is as large as a hornet and even has the hornets rather jerky flight when disturbed, but it has more yellow and lacks the waist between the abdomen and the thorax. British Isles Sesia bembeciformis smaller with black head and shoulders, the eggs are laid in old and isolated trees. Trees in open habitats with little vegetation round the base are a particular favourite, there is one generation each year. S. apiformis flies from mid-June to July and sometimes into early August, the larvae feed on Populus tremula, Populus nigra and Salix caprea. It overwinters as a one and sometimes two times, after which it stays in its cocoon for another winter. Adults are often found on poplar trees straight after emergence, the females lay their eggs at the base of poplar trees, the larval food plant. The larvae hatch and feed mainly just beneath the surface of the bark, exit holes can often be seen near the base of poplar trees and there may be pupal cases nearby. The pupal exuvia may also be seen protruding from the holes on the trunk of the host tree. Adults are most active in sunshine but are seldom seen, emergence from the pupa is in early morning and synchronous. Groups of newly emerged moths can be spotted resting on the trunk for a few hours before flight. The hornet moth is a Palearctic species Swedish moths Lepiforum
41.
Hybrid (biology)
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In biology, a hybrid, also known as a cross breed, is the result of combining, through sexual reproduction, the qualities of two animals or plants of different breeds, varieties, species or genera. Hybrids are not always intermediate between their parents, but can show heterosis or hybrid vigour, often growing larger or taller than either parent, some act before fertilization, others after it. A few animal species and many plant species, however, are the result of hybrid speciation, doubling the number of chromosomes to create polyploids is important in hybrid speciation, because homoploid hybrids are rarely fertile, the polyploid hybrids are allopolyploids. Human impact on the environment has greatly increased the mixing of species, with introduced species worldwide, the genetic mixing may threaten many species with extinction, while genetic erosion in crop plants may be damaging the gene pools of many species for future breeding. Many commercially useful fruits, flowers, garden herbs and trees have been produced by hybridization, one flower, Oenothera lamarckiana, was central to early genetics research into polyploidy. The term hybrid is derived from Latin hybrida, used for such as of a tame sow and a wild boar, or the child of a freeman. The term came into use in English in the 19th century. Conspicuous hybrids are named with portmanteau words, starting in the 1920s with the breeding of tiger-lion hybrids. The cross between two different homozygous lines produces an F1 hybrid that is heterozygous, having two alleles, one contributed by each parent and typically one is dominant and the other recessive. Typically, the F1 generation is also phenotypically homogeneous, producing offspring that are all similar to each other, double cross hybrids result from the cross between two different F1 hybrids. Three-way cross hybrids result from the cross between an F1 hybrid and an inbred line, triple cross hybrids result from the crossing of two different three-way cross hybrids. Top cross hybrids result from the crossing of a top quality or pure-bred male, population hybrids result from the crossing of plants or animals in a population with those of another population. These include interspecific hybrids or crosses between different breeds. e, from the point of view of genetics, different kinds of hybrid can be distinguished as follows, A genetic hybrid carries two different alleles of the same gene. A structural hybrid results from the fusion of gametes that have differing structure in at least one chromosome, a numerical hybrid results from the fusion of gametes having different haploid numbers of chromosomes. A permanent hybrid results when only the heterozygous genotype occurs, as in Oenothera lamarckiana, from the point of view of taxonomy, hybrids differ according to their parentage, Hybrids between different subspecies are called intra-specific hybrids. Offspring resulting from interspecies mating, are called interspecific hybrids, these result in hybrid speciation. Intergeneric hybrids result from matings between different genera, such as sheep and goats. Interfamilial hybrids such as chickens and guineafowl or pheasants are reliably described but extremely rare
42.
Populus nigra
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Populus nigra, the black poplar, is a species of cottonwood poplar, the type species of section Aigeiros of the genus Populus, native to Europe, southwest and central Asia, and northwest Africa. The black poplar is a medium to large-sized deciduous tree, reaching 20–30 m, normally their trunks achieve up to 1.5 m in diameter – however, some unusual individual trees in France have grown old enough to have much larger trunks – more than 3 meters DBH. Their leaves are diamond-shaped to triangular, 5–8 cm long and 6–8 cm broad, the species is dioecious – male and female flowers are on different plants – with flowers in catkins and pollination achieved by the wind. The black poplar grows in low-lying areas of moist ground, like most other pioneer species, the tree is characterized by rapid growth and are able to quickly colonize open areas. There are three established subspecies and some botanists distinguishing a fourth, Populus nigra subsp, leaves and shoots glabrous, bark grey-brown, thick and furrowed. Leaf veins and shoots finely downy, bark grey-brown, thick and furrowed, often with heavy burrs, Mediterranean region, also southwest Asia if var. afghanica not distinguished. Southwest Asia, treated as a cultivar of P. nigra by many botanists, the subspecies betulifolia is one of the rarest trees in Great Britain and Ireland, with only about 7,000 trees known, of which only about 600 have been confirmed as female. Several cultivars have also selected, these being propagated readily by cuttings. The true Lombardy poplar, selected in Lombardy, northern Italy, the growth is fastigiate, with a very narrow crown. Coming from the Mediterranean region, it is adapted to hot, dry summers and grows poorly in humid conditions, as a widely selected species chosen by golf architects in the 1960s, it soon became apparent that the Poplars very invasive roots destroyed land drainage systems. Decades later the courses were removing Poplars stands wholesale. A group of clones derived by crossing Italica with P, both male and female clones are grown. This is the tree most commonly grown in Great Britain and Ireland as Lombardy poplar, betulifolia widely planted in northwest England. It is a clone, and currently seriously threatened by Poplar Scab disease. Another fastigiate clone, of origin, with a rather broader. Most, if not all, specimens of the variety Afghanica are of a single clone and it is fastigiate, similar to Italica, but with a striking whitish bark, it also differs from Italica in being a female clone. This is the common fastigiate poplar in southwest Asia and southeast Europe, black poplar has a large distribution area throughout Europe and is also found in northern Africa and central and west Asia. The distribution area extends from the Mediterranean in the south to approximately 64º latitude in the north and from the British Isles in the west to Kazakhstan, the distribution area also includes the Caucasus and large parts of the Middle East
43.
Populus sect. Populus
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Populus section Populus, of the Populus genus, includes the aspen trees and the white poplar Populus alba. The five typical aspens are all native to regions with cool summers, in the north of the Northern Hemisphere. The White Poplar, by contrast, is native to regions, with hot. These trees are all medium-sized deciduous trees ranging 15–30 metres tall and they are able to survive forest fires because the roots are below the heat of the fire, and new sprouts can grow from the roots. One such colony of American aspen in Utah, given the nickname of Pando, is estimated to be 80,000 years old, fire indirectly benefits aspen trees, since it allows the saplings to flourish in open sunlight in the burned landscape. Young aspen bark is an important seasonal forage for the european hare, Aspen is also a tree of choice of the european beaver. Aspen wood is white and soft, but fairly strong, and has low flammability and it has a number of uses, notably for making matches and paper where its low flammability makes it safer to use than most other woods. Shredded aspen wood is used for packing and stuffing, sometimes called excelsior and it is also a popular animal bedding, since it lacks the phenols associated with pine and juniper, which are thought to cause respiratory system ailments in some animals. Heat-treated aspen is a material for the interiors of a sauna. The Ojibwe used the bark of the trunk as a poultice. Aspen Information Resource, U. K. Quaking Aspen Forests of the Colorado Plateau Bioimages, Populus grandidentata bigtooth aspen Aspen Research Bibliography
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