Annual herb, (15-) 20-50 (-70) cm, simple or with ascending branches from near the base; stem and branches glabrous or very sparingly pilose, with pale ridges. Leaf-blade narrowly linear to broadly ovate or rarely subrotund, (12-) 20-60 (-90) x (2-) 6-30 (-50) mm, glabrous or the petiole and principal veins of the lower surface of the leaf spreading-hairy, acute or acuminate at the apex, longly or (in broader-leaved forms) rapidly narrowed to the base; petiole slender, in the lower leaves up to c. 5 cm, shortening in the upper leaves. Flowers glabrous, white tinged with pink to carmine or red, usually becoming greenish-white in fruit, in long and slender or shorter and denser axillary racemes, long-pedunculate, up to c. 30 cm long, laxer below; peduncles slender, the lower up to c. 14 cm in length, both they and the inflorescence axis glabrous or sparingly spreading-hairy; bracts persistent, deltoid-lanceolate, acuminate, 1-2.75 mm, glabrous, membranous with a green or brownish percurrent midrib, each subtending a very shortly pedunculate partial inflorescence of 3 flowers. Central flower fertile, the 2 membranous, navicular outer perianth segments c. 3-4.5 mm long, oval or oblong, 7-12-nerved (in Asia), acute; the 2-3 inner segments slightly shorter, more delicate, blunt or erose, 1-3-nerved, hyaline, with a darker central vitta; stamens sub-equalling or shorter than the style; style c. 1.5-4 mm, the 2 stigmas finally recurved. Lateral flowers appressed, 1-bracteolate, bracteoles similar in form to the bract, these flowers much reduced and increasingly so in the upper part of the spike (sometimes absent there), modified into accrescent, antler-shaped scales, these scales with the lateral lobes narrow (in Asia) to broad and wing-like. Fruit subglobose, slightly compressed, 2-2.5 mm, bluntly keeled along each side, surmounted by a thick rim or a corona of short, firm processes furnished throughout with verrucae or ridges, style persistent.

Type: Linnean specimen 287/6 (LINN, holotype!).

Distribution: Widespread in southern Asia from tropical Arabia and the Yemen to Afghanistan, India, Ceylon, Malaysia and Indonesia. Also in S., C. and E. tropical Africa and Madagascar. Everywhere as a weed of cultivation and waste places, and occurring as such in Pakistan up to an altitude of at least 1500 m.