Sunflower

The sunflower, Helianthus annuus, is an annual flowering plant in the daisy family, Asteraceae. It is native to North America, where Indigenous peoples domesticated it thousands of years ago before it spread to other parts of the world. A sunflower can develop a tall, sturdy stem and broad leaves, although its size varies with the variety and growing conditions.

What looks like a single large flower is actually a flower head, or capitulum, made up of many tiny flowers. The outer florets form the yellow ray flowers, while the central area contains numerous smaller disc flowers. After pollination, these disc flowers can produce the familiar sunflower seeds. Bees and other insects commonly visit the flower heads to collect pollen and nectar, helping with pollination.

Sunflowers are well adapted to open, sunny environments and grow best when they receive plenty of light. Young plants show a behavior called heliotropism: during part of the day, their developing flower heads can track the movement of the sun. As the flower matures, the head generally stops moving and tends to face east. Sunflowers are cultivated on a large scale for their seeds, which are eaten directly or pressed to produce sunflower oil.

The seeds also provide food for birds and other animals. Depending on the variety, plants may differ greatly in height, seed color, and the amount of oil their seeds contain. Although the sunflower is often associated with warm climates, it can be grown in many temperate regions during the appropriate season. Its rapid growth, conspicuous flower head, and useful seeds have made it both an important crop and a familiar garden plant.