Tridax L.

Herbs, annual or perennial; stems procumbent, decumbent or erect, sparsely or densely hairy, subscapose to leafy. Leaves opposite, rarely alternate above, simple or lobed or divided, entire, serrate to dentate, sessile or petiolate. Inflorescence mostly of solitary heads; peduncles stout, erect, elongate, pubescent, often with gland tipped hairs. Heads discoid or radiate, campanulate. Involucral bracts greenish, often purplish at the apex, 2 - 3 seriate, unequal, purple margined, inner scarious. Ray florets white or yellow, hilabiate, often pubescent. Disc florets yellow, greenish-yellow, or whitish to purplish; limb tubular, glabrous or pubescent, 5-lobed; lobes equal, sublanceolate, acute or obtuse, erect or reflexed. Anthers nearly exserted, sagittate. Style branches recurved or revolute. Achenes turbinate, narrowly obconic to subcylindric, terete to ridged, glabrous to densely pubescent. Pappus usually of about 20, plumose bristles or fimbriate, linear-lanceolate scales, rarely absent.

ca 27 species, 1 in India.

Literature. POWELL. A.M. (1965). Taxonomy of Tridax (Compolitae). Brittonia 17: 47-96

List of Lower Taxa