Syst. Nat. ed. 10, 2: 1221. 1759.
Annuals, mostly 30–50(–100) cm. Stems greenish, becoming purplish or yellowish, unbranched or sparingly branched distal to bases, strigose. Leaf blades 3–5-nerved, ovate to elliptic or broadly lanceolate, 25–70 × 8–35 mm, scabrellous. Peduncles 10–50(–70) mm. Involucres narrowly to broadly campanulate, 9–18 × 10–20 mm. Phyllaries obovate to oblong, becoming scarious, glabrous, apices rounded, usually entire or erose, sometimes ciliate. Paleae red to purple or yellow, apices obtuse, erose or subentire. Ray florets 6–15(–21); corollas usually scarlet red or maroon, sometimes yellow, laminae linear to spatulate, 8–25 mm. Disc florets 12–50; corollas yellow, 5–6 mm, lobes ca. 1 mm. Cypselae 7–10 mm, 3-angled (ray) or compressed (disc), ribbed, ciliate; pappi usually of 1 stout awn 4–6 mm (from shoulders of cypselae). 2n = 24.
Phenology: Flowering summer–fall.
Habitat: Rocky roadsides, ravines, calcareous soils
Elevation: 1200–1600 m
Ariz., Fla., Ga., N.C., S.C., Mexico, West Indies (Hispaniola), Central America, South America, introduced in Asia (China), South Africa, Australia.
Zinnia peruviana is presumably native in southern Arizona and reported as naturalized in southeastern United States.