A big yellow sunflower. Sunflower (Helianthus annuus) is an annual plant native to the Americas that possess a large inflorescence (flowering head). The sunflower got its name from its huge fiery blooms, whose shape and image is often used to depict the sun. The sunflower has a rough, hairy stem, broad, coarsely toothed, rough leaves and circular heads of flowers. The heads consist of 1,000-2,000 individual flowers joined together by a receptacle base.