Onion

Allium cepa

The onion , which is also known as the bulb onion, common onion is the most widely cultivated species of the genus ''Allium.'' The genus ''Allium'' also contains a number of other species variously referred to as onions and cultivated for food, such as the Japanese bunching onion , Egyptian onion , and Canada onion . The name "wild onion" is applied to a number of ''Allium'' species. Onion is most frequently a biennial, although it can also be a triennial or a perennial.

The vast majority of cultivars of ''A. cepa'' belong to the "common onion group" and are usually referred to simply as "onions". The Aggregatum Group of cultivars includes both shallots and potato onions.

''Allium cepa'' is known exclusively in cultivation, but related wild species occur in Central Asia. The most closely related species include ''Allium vavilovii'' and ''Allium asarense'' from Iran. However, Zohary and Hopf warn that "there are doubts whether the ''A. vavilovii'' collections tested represent genuine wild material or only feral derivatives of the crop."

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Allium cepa  Allium cepa,Flora,Geotagged,Germany,Macro,Onion,Plants,bloom,edible

Naming

Scallions or salad onions may be grown from the Welsh onion as well as from ''A. cepa''. Young plants of ''A. fistulosum'' and ''A. cepa'' look very similar, but may be distinguished by their leaves, which are circular in cross-section in ''A. fistulosum'' rather than flattened on one side.
Onion Flower (Allium)  Allium cepa,Flowers,Geotagged,Onion,United Kingdom

Uses

Onions are often chopped and used as an ingredient in various hearty warm dishes, and may also used as a main ingredient in their own right, for example in French onion soup or onion chutney. They are also used raw in cold salads. Onions are also used as a thickening agent for curries providing a bulk of the base. Onions pickled in vinegar are eaten as a snack. These are often served as a side serving in fish and chip shops throughout the United Kingdom and Australia, often served with cheese in the United Kingdom, and as "pickled onions" in Eastern Europe. Fresh onion has a pungent, persistent, even irritating taste, but when sautéed, onion becomes sweet and much less pungent.Onions have particularly large cells that are readily observed at low magnification; consequently, onion tissue is frequently used in science education for demonstrating microscope usage.

Onion skins have been used for dye.Bulbs from the onion family are thought to have been used as a food source for millennia. In Bronze Age settlements, traces of onion remains were found alongside date stones and fig remains that date back to 5000 BC.

However, it is not clear if these were cultivated onions. Archaeological and literary evidence such as the Book of Numbers 11:5 suggests cultivation probably took place around two thousand years later in ancient Egypt, at the same time that leeks and garlic were cultivated. Workers who built the Egyptian pyramids may have been fed radishes and onions.

The onion is easily propagated, transported and stored. The ancient Egyptians worshipped it, believing its spherical shape and concentric rings symbolized eternal life. Onions were even used in Egyptian burials, as evidenced by onion traces being found in the eye sockets of Ramesses IV.

In ancient Greece, athletes ate large quantities of onion because it was believed to lighten the balance of blood. Roman gladiators were rubbed down with onion to firm up their muscles. In the Middle Ages, onions were such an important food that people would pay their rent with onions, and even give them as gifts. Doctors were known to prescribe onions to facilitate bowel movements and erections, and also to relieve headaches, coughs, snakebite and hair loss.

The cultivated onion was introduced to North America by Christopher Columbus on his 1492 expedition to Hispaniola; however, they found that strains of wild onions already grew throughout North America. Native American Indians used wild onions in a variety of ways, eating them raw or cooked, as a seasoning or as a vegetable. Such onions were also used in syrups, as poultices, as an ingredient in dyes and even as toys. According to diaries of colonists, bulb onions were planted as soon as the Pilgrim fathers could clear the land in 1648.

Onions were also prescribed by doctors in the early 16th century to help with infertility in women, and even dogs, cats and cattle and many other household pets. However, recent evidence has shown that dogs, cats, guinea pigs, and other animals should not be given onions in any form, due to toxicity during digestion.

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Taxonomy
KingdomPlantae
DivisionAngiosperms
ClassMonocots
OrderAsparagales
FamilyAmaryllidaceae
GenusAllium
SpeciesA. cepa