Сunflower (Helianthus) is a genus of plants comprising about 52 species in the Asteraceae family, all of which are native to North America. The common name "sunflower" also applies to the popular annual species Helianthus annuus. The genus is one of many in the Asteraceae that are known as sunflowers. Technical feature that is distinguished in this genus, but requires a microscope to see, is the presence of a prominent, multicellular appendage at the apex of the style. The domesticated sunflower, Helianthus annuus, is the most familiar species.