The common sunflower (Helianthus annuus) is a species of large annual forb of the daisy family Asteraceae.

[3] Sunflower leaves are broad, coarsely toothed, rough and mostly alternate; those near the bottom are largest and commonly heart-shaped.

[5][6] This old misconception was disputed in 1597 by the English botanist John Gerard, who grew sunflowers in his famous herbal garden: "[some] have reported it to turn with the Sun, the which I could never observe, although I have endeavored to find out the truth of it.

"[7] The uniform alignment of sunflower heads in a field might give some people the false impression that the flowers are tracking the Sun.

[17] This is expressed in polar coordinates where θ is the angle, r is the radius or distance from the center, and n is the index number of the floret and c is a constant scaling factor.

[4] Outside of cultivation, the common sunflower is found on moist clay-based soils in areas with climates similar to Texas.

According to Plants of the World Online (POWO), it is native to Arizona, California, and Nevada in the present-day United States and to all parts of Mexico except the Gulf Coast and southeast.

[23] Though not giving much detail, the Missouri Botanical Garden Plant Finder also lists it as native to the Western United States and Canada.

[24] The information published by the Biota of North America Program (BONAP) largely agrees with this, showing the common sunflower as native to states west of the Mississippi, though also listed as a noxious weed in Iowa, Minnesota, and Texas.

[23] One of the major threats that sunflowers face today is Fusarium, a filamentous fungus that is found largely in soil and plants.

When such shallow planting is done in moist and soaked earth or soil, it increases the chances of diseases such as downy mildew.

[citation needed] Common sunflower was one of several plants cultivated by Native Americans in prehistoric North America as part of the Eastern Agricultural Complex, which also included corn, beans, squash, and a variety of other crops.

[32] 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.

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.

[37] 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.

[citation needed] In 2020, world production of sunflower seeds was 50 million tonnes, led by Russia and Ukraine, with 53% combined of the total.

These hybrid species generally have a higher fitness and carry properties or characteristics that farmers look for, such as resistance to pathogens.

Plants treated with an external application of the hormone display a temporary restoration of elongation growth patterns.

Being easy to grow and producing spectacular results in any good, moist soil in full sun, they are a favourite subject for children.

Native Americans had multiple uses for sunflowers in the past, such as in bread, medical ointments, dyes and body paints.

[58] Among the Zuni people, the fresh or dried root is chewed by the medicine man before sucking venom from a snakebite and applying a poultice to the wound.

The decrease in yield can be attributed to the production of phenolic compounds which are used to reduce competition for nutrients in nutrient-poor growing areas of the common sunflower.

[66] Helianthus annuus can be used in phytoremediation to extract pollutants from soil such as lead and other heavy metals, such as cadmium, zinc, cesium, strontium, and uranium.

The phytoremediation process begins by absorbing the heavy metal(s) through the roots, which gradually accumulate in other areas, such as the shoots and leaves.

[69][70][71] According to Iroquois mythology, the first sunflowers grew out of Earth Woman's legs after she died giving birth to her twin sons, Sapling and Flint.

In July 2015, viable seeds were acquired from the field where Malaysia Airlines Flight 17 crashed on a year earlier and were grown in tribute to the 15 Dutch residents of Hilversum who were killed.

[77] Earlier that year, Fairfax chief correspondent Paul McGeough and photographer Kate Geraghty had collected 1.5 kg of sunflower seeds from the wreck site for family and friends of the 38 Australian victims, who aimed to give them a poignant symbol of hope.

[80] Ukrainians used sunflower as a main source of cooking oil instead of butter or lard forbidden by the Orthodox Church when observing Lent.

In June 1996, U.S., Russian, and Ukrainian officials planted sunflowers at the Pervomaysk missile base where Soviet nuclear weapons were formerly placed.

The Hidden Disabilities Sunflower was first used as a visible symbol (typically worn on a lanyard) in May 2016 at London Gatwick Airport.