A sunflower is a type of large flowering plant that belongs to the genus Helianthus. It is commonly grown for its edible seeds, which are rich in oil and protein. Sunflowers are also popular as ornamental plants, because they have bright yellow petals that resemble the sun. Sunflowers can grow up to 3 metres (10 feet) tall, and their flower heads can reach 30 centimetres (12 inches) in diameter.