Description from Flora of China
Zinnia multiflora Linnaeus; Z. pauciflora Linnaeus.
Annuals, mostly 30-50(-100) cm. Stems greenish, becoming purplish or yellowish, unbranched or sparingly branched distal to bases, strigose. Leaf blade ovate to elliptic or broadly lanceolate, 25-70 × 8-35 mm, 3-5-veined, scaberulose. Peduncles 10-50(-70) mm; involucres narrowly to broadly campanulate, 9-18 × 10-20 mm; phyllaries obovate to oblong, becoming scarious, glabrous, margin usually entire or erose, sometimes ciliate, apex rounded; paleae red to purple or yellow, margin erose or subentire, apex obtuse. Ray florets 6-15(-21); corollas usually scarlet red or maroon, sometimes yellow, lamina linear to spatulate, 8-25 mm. Disk florets 12-50; corollas yellow, 5-6 mm, lobes ca. 1 mm. Achenes 7-10 mm, ray achenes 3-angled, disk achenes compressed, ribbed, setuliferous; pappus usually of 1 stout awn 4-6 mm. Fl. Jun-Nov, fr. Jul-Nov. 2n = 24.
Roadsides, grasslands, mountain slopes; below 1300 m. Introduced and naturalized in Gansu, Hebei, Henan, Sichuan, Yunnan [probably native to Mexico, but widespread in South America].