Parthenium L.

Herbs or shrubs, aromatic, annual or perennial with ridgea, terete stem. Leaves alternate, entire or highly divided. Inflorescence with solitary head or terminal corymb or panicle. Heads radiate. Involucral bracts biseriate, generally 5 in each series. Ray florets 5; corolla white, corolla and styles persistent at the apex of the achene. Disc florets with tubular corolla, 5 lobed. Anthers with white or yellew pollen. Achene a complex structure obcompressed, rounded to somewhat keeled on the inner face, puberulent, margins thickened into rib-like structures which are attached to a pair of sterile disc florets; bracts fall together at matutiry. Pappus of 2 - 3 awns or scales or even absent.

Throughout the western hemisphere; ca 16 species, 1 in India.

List of Lower Taxa