2. Tagetes patula L. (French marigold)

Pl. 290 c, d; Map 1234

Stems 10–80(–120) cm long. Heads mostly 3.5–5.0 cm in diameter (including the spreading ray corollas), the stalk not or only slightly inflated or swollen toward the tip, hollow or less commonly solid. Involucre 12–16 mm long. Ray florets with the corolla 8–15 mm long, yellow or orange but often with a red or reddish brown region toward the base, sometimes nearly uniformly reddish brown. Disc florets with the corolla 8–13 mm long. Pappus scales variously 5–10 mm long. Fruits 7–9 mm long. 2n=48. July–October.

Introduced, uncommon, known thus far only from the city of St. Louis (probably native of Mexico and Central America, widely introduced in tropical and temperate regions nearly worldwide). Railroads.

This species was first reported for the state by Mühlenbach (1979), based on his botanical surveys of the St. Louis railyards. Its uses are similar to those of T. erecta, discussed above. Because it is a tetraploid (2n=48), presumably derived following past hybridization between diploid progenitors, it is unclear whether this species ever had a native distribution in Latin America (Neher, 1966).