The sunflower (Helianthus annuus) is an annual plant native to the Americas in the family Asteraceae, with a large flowering hea (inflorescence). The stem of the flower can grow as high as 3 metres tall, with the flower head reaching up to 30 cm in diameter with the "large" seeds. The term "sunflower" is also used to refer to all plants of the genus Helianthus, many of which are perennial plants.