Zinnia elegans (syn. Zinnia violacea) known as youth-and-age, common zinnia or elegant zinnia, is an annual flowering plant in the family Asteraceae. It is native to Mexico but grown as an ornamental in many places and naturalised in several places, including scattered locations in South and Central America, the West Indies, the United States, Australia, and Italy.
The uncultivated plant grows to about 15 cm (5.27 in) in height. It has solitary flower heads about 5 cm (2 in) across. The purple ray florets surround black and yellow discs. The lanceolate leaves are opposite the flower heads. Flowering occurs during the summer months.
The species was first collected in 1789 at Tixtla, Guerrero, by Sessé and Mociño. It was formally described as Zinnia violacea by Cavanilles in 1791. Jacquin described it again in 1792 as Zinnia elegans, which was the name that Sessé and Moçiño had used in their manuscript of Plantae Novae Hispaniae, which was not published until 1890. The genus was named by Carl von Linné after the German botanist Johann Gottfried Zinn, who described the species now known as Zinnia peruviana in 1757 as Rudbeckia foliis oppositis hirsutis ovato-acutis, calyce imbricatus, radii petalis pistillatis. Linné realised that it was not a Rudbeckia.