Helianthus annuus is the Latin or scientific name for the common sunflower. This particular sunflower is native to Central America, but is cultivated throughout the Americas, as well as in Russia. A flowering annual plant, it is easily distinguishable from other flowers due to its large, bright blooms and relatively great height. Most cultivars grow from 8 feet (about 2.4 m) to 15 feet (about 6 m) tall.
The bloom of the Helianthus annuus is actually a composite flower, or head, that is made up of many small flowers, or florets. This head consists of a number of intensely colored, triangular florets which radiate out from a circular center of very small brownish-purple florets. Most of the heads are relatively large – between 8 inches (about 20 cm) and 12 inches (about 30.5 cm) in diameter.
Smaller florets are called disk florets, while the larger florets are called ray florets. The disk florets, which are crowded together in a spiral pattern, eventually produce sunflower seeds, while the ray florets are sterile. Ray florets vary in color from dark maroon to pale yellow. Most Helianthus annuus ray florets, however, are bright yellow. Because of this, and because the head of the flower is always oriented in the direction of the sun, it is easy to understand why the flower is commonly known as the sunflower.
There are many varieties of the plant, including the American giant hybrid, Aztec sun, giant primrose, lemon queen, ring of fire, strawberry blonde, and yellow empress. Smaller, dwarf varieties of the flower include the teddy bear, sunspot, and autumn beauty. Russian giant Helianthus annuus plants may attain heights of up to 12 feet (about 3.7 m). Italian white Helianthus annuus heads have black and white florets, while such strains as the evening sun may have ray florets that are almost pink.
In addition to being grown for decorative uses, the plants are also cultivated for commercial purposes. Hardy and easy to grow, the plants are valued for their seeds, which may be eaten or used to produce sunflower oil. Helianthus annuus seeds and oil were historically important in many Native American cuisines, and these products are still consumed worldwide. Russia and the state of Kansas are the largest producers of sunflower oil; the plant is the official flower in Kansas.
Helianthus annuus is a member of the aster/daisy family. It is also related to the perennial sunflower Helianthus maximillianii. A distant relative of the plant is the Jerusalem artichoke, Helianthus tuberosus. Also known as the sunchoke, this edible tuber is relished for its delicate, artichoke-like flavor.