Mexican Sunflowers

Tithonia is a genus of flowering plants in the tribe Heliantheae within the family Asteraceae.

Tithonia has a center of distribution in Mexico but with one species extending into the Southwestern United States and several native to Central America. Two species, T. diversifolia and T. rotundifolia, are widely cultivated and have escaped to become weeds in tropical and subtropical areas around the world. T. rotundifolia makes a nice fresh cut flower, flowering in mid- to late-summer in the Northern hemisphere. The distinguishing feature of the genus is the peduncle, which is fistulose (meaning hollow and flaring toward the apex). The plants are coarse annual or perennial herbs or shrubs, and one species, T. koelzii, is a small tree.