Description from Flora of China
Annual or perennial herbs or subshrubs. Stems prostrate or erect. Leaves cauline, opposite or subopposite, sessile or shortly petiolate; blade acerose, elliptic, linear-lanceolate, lanceolate, linear, oblong, or ovate, both surfaces hairy, usually gland-dotted, base rounded to cuneate, sheathing stem, margin entire. Synflorescence of terminal solitary capitula. Capitula usually radiate; involucres campanulate, cylindric, to hemispheric; phyllaries persistent, 3- or 4-seriate; receptacle conical, paleate. Ray florets female, fertile; corollas yellow, orange, red, maroon, purple, or white. Disk florets bisexual, fertile; corollas usually yellow to reddish, sometimes purple tinged, tubes much shorter than cylindric throats, lobes 5, lanceolate-ovate. Achenes 3-angled or flattened, disk achenes wingless; pappus absent, or persistent, of 1-3(or 4) awns or toothlike scales.
Zinnia angustifolia Kunth, Z. elegans Jacquin, nom. cons. (Z. violacea Cavanilles), and Z. haageana Regel are cultivated in China.
See Torres, Brittonia 15(1): 1-25. 1963.
About 25 species: Mexico, United States; Central and South America; one species (introduced) in China.