Sunflower facts for kids
Quick facts for kids Sunflower |
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Helianthus
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H. annuus
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| Helianthus annuus |
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The sunflower (Helianthus annuus) is an annual plant in the family Asteraceae, with a large flower head (capitulum). The stem of the flower can grow up to 3 metres tall, with a flower head that can be 30 cm wide. Other types of sunflowers include the California Royal Sunflower, which has a burgundy (red + purple) flower head.
The flower head is actually an inflorescence made of hundreds or thousands of tiny flowers called florets. The central florets look like the centre of a normal flower, and the outer florets look like yellow petals. All together they make up a "false flower" or pseudanthium. The benefit to the plant is that it is very easily seen by the insects and birds which pollinate it, and it produces thousands of seeds.
The sunflower is the state flower of Kansas. That is why Kansas is sometimes called the Sunflower State. To grow well, sunflowers need full sun. They grow best in fertile, wet, well-drained soil with a lot of mulch. In commercial planting, seeds are planted 45 cm (1.5 ft) apart and 2.5 cm (1 in) deep.
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Description
The outer petal-bearing florets are the sterile florets and can be yellow, red, orange, or other colours. The florets inside the circular head are called disc florets, which mature into seeds.
The flower petals within the sunflower's cluster are always in a spiral pattern. Generally, each floret is oriented toward the next by approximately the golden angle, 137.5°, producing a pattern of interconnecting spirals, where the number of left spirals and the number of right spirals are successive Fibonacci numbers. Typically, there are 34 spirals in one direction and 55 in the other; on a very large sunflower there could be 89 in one direction and 144 in the other.
Sunflowers commonly grow to heights between 1.5 and 3.5 m (5–12 ft.). The tallest sunflower confirmed by Guinness World Records is 9.17 m (2014, Germany). In 16th century Europe the record was already 7.3 m (24 ft., Spain). Most cultivars are variants of H. annuus, but four other species (all perennials) are also domesticated. This includes H. tuberosus, the Jerusalem Artichoke, which produces edible tubers.
History
Sunflower was one of several plants cultivated by Native Americans in prehistoric North America. Although it was commonly accepted that the sunflower was first domesticated in what is now the southeastern US, roughly 5,000 years ago, there is evidence that it was first domesticated in Mexico around 2600 BCE. These crops were found in Tabasco, Mexico, at the San Andres dig site. The earliest known examples in the US of a fully domesticated sunflower have been found in Tennessee, and date to around 2300 BCE. Other very early examples come from rockshelter sites in Eastern Kentucky. Many indigenous American peoples used the sunflower as the symbol of their solar deity, including the Aztecs and the Otomi of Mexico and the Incas in South America. In 1510, early Spanish explorers encountered the sunflower in the Americas and carried its seeds back to Europe.
They then were introduced to the Russian Empire, where oilseed cultivators were located, and the flowers were developed and grown on an industrial scale. The Russian Empire reintroduced this oilseed cultivation process to North America in the mid-20th century; North America began their commercial era of sunflower production and breeding. New breeds of the Helianthus spp. began to become more prominent in new geographical areas. During the 18th century, the use of sunflower oil became very popular in Russia, particularly with members of the Russian Orthodox Church, because only plant-based fats were allowed during Lent, according to fasting traditions. In the early 19th century, it was first commercialized in the village of Alexeyevka in Voronezh Governorate by the merchant named Daniil Bokaryov, who developed a technology suitable for its large-scale extraction, and quickly spread around. The town's coat of arms has included an image of a sunflower ever since.
Of the four plants known to have been domesticated in eastern North America and to have become important agricultural commodities, the sunflower is currently the most economically important.
As food
Sunflower "whole seed" (fruit) are sold as a snack food, after roasting in ovens, with or without salt added. Sunflowers can be processed into a peanut butter alternative, Sunbutter. In Germany, it is mixed together with rye flour to make Sonnenblumenkernbrot (literally: sunflower whole seed bread), which is quite popular in German-speaking Europe. It is also sold as food for birds and can be used directly in cooking and salads. Sunflower oil, extracted from the seeds, is used for cooking, as a carrier oil and to produce margarine and biodiesel, as it is cheaper than olive oil. A range of sunflower varieties exist with differing fatty acid compositions; some 'high oleic' types contain a higher level of healthy monounsaturated fats in their oil than Olive oil.
The cake remaining after the seeds have been processed for oil is used as a livestock feed. Some recently developed cultivars have drooping heads. These cultivars are less attractive to gardeners growing the flowers as ornamental plants, but appeal to farmers, because they reduce bird damage and losses from some plant diseases. Sunflowers also produce latex and are the subject of experiments to improve their suitability as an alternative crop for producing hypoallergenic rubber. Traditionally, several Native American groups planted sunflowers on the north edges of their gardens as a "fourth sister" to the better known three sisters combination of corn, beans, and squash. Annual species are often planted for their allelopathic properties. Sunflowers may also be used to extract toxic ingredients from soil, such as lead, arsenic and uranium. They were used to remove uranium, cesium-137, and strontium-90 from soil after the Chernobyl disaster (see phytoremediation).
Images for kids
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Sunflower bud beginning to emerge
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Red sunflower in the sun
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Close-up of a sunflower
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The disk of a sunflower is made up of many little flowers. The ray flowers here are dried up.
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A field of sunflowers in North Carolina.
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Sunflower leaf structure
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Prairie sunflower (H. petiolaris)
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Giant sunflower (H. giganteus)
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Red Sunflower
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Helianthus 'Strawberry Blonde'
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Willowleaf sunflower (H. salicifolius)
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Flower bud of Sunflower, not yet bloomed into a full-size flower
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Jerusalem artichoke (H. tuberosus)
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Leaves of Sunflower plant
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Rear view of Sunflower head
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Helianthus annuus
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Field of Sunflowers
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See also
In Spanish: Girasol para niños
