230. Tithonia Desfontaines ex Jussieu, Gen. Pl. 189. 1789.
肿柄菊属 zhong bing ju shu
Annuals, perennials, subshrubs, or shrubs. Stems erect, branched. Leaves all or mostly cauline, opposite (proximal) or mostly alternate, petiolate or sessile; blade mostly deltate or pentagonal, sometimes 3- or 5-lobed, often (1 or)3- or 5-veined, both surfaces glabrous, ± hirsute, pilose, soft pubescent, or villous, often gland-dotted, base truncate or auriculate, ultimate margin serrate to crenate. Capitula borne singly; peduncles usually distally dilated, fistulose; involucres campanulate to hemispheric; phyllaries persistent, 2-5-seriate; receptacles hemispheric to convex, paleate. Ray florets 8-30, neuter; corollas yellow or orange. Disk florets bisexual, fertile; corollas yellow, tubes shorter than throats, lobes 5, triangular. Achenes compressed or flattened, often 3- or 4-angled or biconvex, cuneiform in silhouette, sometimes with basal elaiosomes; pappus absent or coroniform, of connate scales, 1 or 2 scales sometimes subulate to aristate. x = 17.
About 11 species: Mexico, SW United States; Central America; one species (introduced) in China.
See La Duke, Rhodora 84: 463-522. 1982.
Tithonia rotundifolia (Miller) S. F. Blake is cultivated in China.