Pear Tree Diseases
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Pear Tree Diseases
Pears are fruits produced and consumed around the world, growing on a tree and harvested in the Northern Hemisphere in late summer into October. The pear tree and shrub are a species of genus ''Pyrus'' , in the family Rosaceae, bearing the pomaceous fruit of the same name. Several species of pears are valued for their edible fruit and juices, while others are cultivated as trees. The tree is medium-sized and native to coastal and mildly temperate regions of Europe, North Africa, and Asia. Pear wood is one of the preferred materials in the manufacture of high-quality woodwind instruments and furniture. About 3,000 known varieties of pears are grown worldwide, which vary in both shape and taste. The fruit is consumed fresh, canned, as juice, or dried. Etymology The word ''pear'' is probably from Germanic ''pera'' as a loanword of Vulgar Latin ''pira'', the plural of ''pirum'', akin to Greek ''apios'' (from Mycenaean ''ápisos''), of Semitic origin (''pirâ''), meaning "fr ...
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Pyrus Communis
''Pyrus communis'', the common pear, is a species of pear native to central and eastern Europe, and western Asia. It is one of the most important fruits of temperate regions, being the species from which most orchard pear cultivars grown in Europe, North America, and Australia have been developed. Two other species of pear, the Nashi pear (''Pyrus pyrifolia'') and the hybrid Chinese white or ya pear ('' Pyrus × bretschneideri'', ) are more widely grown in East Asia. Subtaxa The following subspecies are currently accepted: *''Pyrus communis'' subsp. ''caucasica'' – Turkey, Caucasus *''Pyrus communis'' subsp. ''communis'' – Entire range except Caucasus Origin The cultivated Common pear (''P. communis'' subsp. ''communis'') is thought to be descended from two subspecies of wild pears, categorized as ''P. communis'' subsp.'' pyraster'' (syn. ''P. pyraster'') and ''P. communis'' subsp. ''caucasica'' (syn. ''P. caucasica''), which are interfertile with domesticated pears. A ...
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Perseus Project
The Perseus Project is a digital library project of Tufts University, which assembles digital collections of humanities resources. Version 4.0 is also known as the "Perseus Hopper", and it is hosted by the Department of Classical Studies. The project is mirrored by the Max Planck Society in Berlin, Germany, as well as by the University of Chicago. History The project was founded in 1987 to collect and present materials for the study of ancient Greece. It has published two CD-ROMs and established the Perseus Digital Library on the World Wide Web in 1995. The project has expanded its original scope; current collections cover Greco-Roman classics and the English Renaissance. Other materials, such as the papers of Edwin Bolles and the history of Tufts University, have been moved into the Tufts Digital Library. The editor-in-chief of the project is Gregory R. Crane, the Tufts Winnick Family Chair in Technology and Entrepreneurship. He has held that position since the founding of t ...
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Pome
In botany, a pome is a type of fruit produced by flowering plants in the subtribe Malinae of the family Rosaceae. Well-known pomes include the apple, pear, and quince. Etymology The word ''pome'' entered English in the late 14th century, and referred to an apple or an apple-shaped object. It derived from the Old French word for "apple": (12th century; modern French is ), which in turn derived from the Late Latin or Vulgar Latin word "apple", originally the plural of Latin "fruit", later "apple". Morphology A pome is an accessory fruit composed of one or more carpels surrounded by accessory tissue. The accessory tissue is interpreted by some specialists as an extension of the receptacle and is then referred to as "fruit cortex",Esau, K. 1977. ''Anatomy of seed plants''. John Wiley and Sons, New York. and by others as a fused hypanthium (floral cup). It is the most edible part of this fruit. The carpels of a pome are fused within the "core". Although the epicarp, mesoca ...
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Apple
An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, where its wild ancestor, '' Malus sieversii'', is still found today. Apples have been grown for thousands of years in Asia and Europe and were brought to North America by European colonists. Apples have religious and mythological significance in many cultures, including Norse, Greek, and European Christian tradition. Apples grown from seed tend to be very different from those of their parents, and the resultant fruit frequently lacks desired characteristics. Generally, apple cultivars are propagated by clonal grafting onto rootstocks. Apple trees grown without rootstocks tend to be larger and much slower to fruit after planting. Rootstocks are used to control the speed of growth and the size of the resulting tree, allowing for easier harvesting. There are mo ...
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Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism for the union of sperm with eggs. Flowers may facilitate outcrossing (fusion of sperm and eggs from different individuals in a population) resulting from cross-pollination or allow selfing (fusion of sperm and egg from the same flower) when self-pollination occurs. There are two types of pollination: self-pollination and cross-pollination. Self-pollination occurs when the pollen from the anther is deposited on the stigma of the same flower, or another flower on the same plant. Cross-pollination is when pollen is transferred from the anther of one flower to the stigma of another flower on a different individual of the same species. Self-pollination happens in flowers where the stamen and carpel mature at the same time, and are posi ...
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Evergreen
In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which completely lose their foliage during the winter or dry season. Evergreen species There are many different kinds of evergreen plants, both trees and shrubs. Evergreens include: *Most species of conifers (e.g., pine, hemlock, blue spruce, and red cedar), but not all (e.g., larch) *Live oak, holly, and "ancient" gymnosperms such as cycads *Most angiosperms from frost-free climates, and rainforest trees *All Eucalypts * Clubmosses and relatives * Bamboos The Latin binomial term , meaning "always green", refers to the evergreen nature of the plant, for instance :'' Cupressus sempervirens'' (a cypress) :''Lonicera sempervirens'' (a honeysuckle) :''Sequoia sempervirens'' (a sequoia) Leaf longevity in evergreen plants varies from a ...
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Deciduous
In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, after flowering; and to the shedding of ripe fruit. The antonym of ''deciduous'' in the botanical sense is evergreen. Generally, the term "deciduous" means "the dropping of a part that is no longer needed or useful" and the "falling away after its purpose is finished". In plants, it is the result of natural processes. "Deciduous" has a similar meaning when referring to animal parts, such as deciduous antlers in deer, deciduous teeth (baby teeth) in some mammals (including humans); or decidua, the uterine lining that sheds off after birth. Botany 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. This process is called ...
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Leaf
A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, flower, and fruit collectively form the shoot system. In most leaves, the primary photosynthetic tissue is the palisade mesophyll and is located on the upper side of the blade or lamina of the leaf but in some species, including the mature foliage of ''Eucalyptus'', palisade mesophyll is present on both sides and the leaves are said to be isobilateral. Most leaves are flattened and have distinct upper (adaxial) and lower ( abaxial) surfaces that differ in color, hairiness, the number of stomata (pores that intake and output gases), the amount and structure of epicuticular wax and other features. Leaves are mostly green in color due to the presence of a compound called chlorophyll that is essential for photosynthesis as it absorbs light ...
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Shrub
A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple stems and shorter height, less than tall. Small shrubs, less than 2 m (6.6 ft) tall are sometimes termed as subshrubs. Many botanical groups have species that are shrubs, and others that are trees and herbaceous plants instead. Some definitions state that a shrub is less than and a tree is over 6 m. Others use as the cut-off point for classification. Many species of tree may not reach this mature height because of hostile less than ideal growing conditions, and resemble a shrub-sized plant. However, such species have the potential to grow taller under the ideal growing conditions for that plant. In terms of longevity, most shrubs fit in a class between perennials and trees; some may only last about fiv ...
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Old World
The "Old World" is a term for Afro-Eurasia that originated in Europe , after Europeans became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia, which were previously thought of by their inhabitants as comprising the entire world, with the "New World", a term for the newly encountered lands of the Western Hemisphere, particularly the Americas. Etymology In the context of archaeology and world history, the term "Old World" includes those parts of the world which were in (indirect) cultural contact from the Bronze Age onwards, resulting in the parallel development of the early civilizations, mostly in the temperate zone between roughly the 45th and 25th parallels north, in the area of the Mediterranean, including North Africa. It also included Mesopotamia, the Persian plateau, the Indian subcontinent, China, and parts of Sub-Saharan Africa. These regions were connected via the Silk Road trade route, and they have a pr ...
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Native Plant
In biogeography, a native species is indigenous to a given region or ecosystem if its presence in that region is the result of only local natural evolution (though often popularised as "with no human intervention") during history. The term is equivalent to the concept of indigenous or autochthonous species. Every wild organism (as opposed to a domesticated organism) is known as an introduced species within the regions where it was anthropogenically introduced. If an introduced species causes substantial ecological, environmental, and/or economic damage, it may be regarded more specifically as an invasive species. The notion of nativity is often a blurred concept, as it is a function of both time and political boundaries. Over long periods of time, local conditions and migratory patterns are constantly changing as tectonic plates move, join, and split. Natural climate change (which is much slower than human-caused climate change) changes sea level, ice cover, temperature, and r ...
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