Annuals, biennials, perennials, subshrubs, or shrubs. Stems erect, usually branched. Leaves usually cauline, sometimes in rosettes, alternate, petiolate or sessile; blade elliptic, lanceolate, linear, lyrate, oblanceolate, obovate, ovate, orbicular-deltate, or spatulate, sometimes pinnately (1 or)2-lobed, both surfaces usually hairy and gland-dotted (at least abaxial), ultimate margin entire or toothed. Capitula usually radiate, sometimes ± disciform; involucres hemispheric; phyllaries deciduous, 2-seriate, outer 5(-8) herbaceous to scarious, inner 5-8 scarious to membranous; receptacle flat to conical; paleae cuneate to flabelliform, scarious or membranous, distally papillate and/or fimbrillate, all or peripheral each ± enfolding a disk floret. Ray female florets 5(-8), fertile; corollas ochroleucous, tubes stout, glandular. Disk florets functionally male; corollas ochroleucous, funnelform, lobes 5. Achenes oblanceolate, obovate, or pyriform, often obcompressed; pappus absent. x = 9.

Parthenium argentatum A. Gray is cultivated in China.

See Rollins, Contr. Gray Herb. 172: 1-73. 1950.

About 16 species: North America to South America, including the Caribbean; one species (introduced) in China.