Acanthospermum Schrank

Herbs, annual, dichotomously branched, pubescent. Leaves opposite, simple or pinnatifid. Inflorescence of solitary heads in the axils or at forks of branches. Heads radiate, small, subsessile to sessile. Involucral bracts biseriate; outer elliptic-ovate, foliaceous; inner completely enveloping ray achenes. Receptacle convex; pales membranous. Ray florets 5 - 6; corolla yellow, emarginate or tridentate at apex; tube equalling the corolla or slightly shorter. Disc florets many; corolla campanulate, 5-lobed. Anthers cordate-saaittate. Style clavate, obtuse, hispidulous, undivided. Achenes of ray florets trigonous, slightly compressed, enveloped by inner involucral bracts, tough, echinate with straight or uncinate prickles. Pappus absent.

Distributed in W. Indies, S. America and Madagascar; ca 10 species, 1 in India.

Literature. BLAKE. S.F. (1921). Revision of the genus Acanthospermuim Contr. U.S. Nat. Herb. 20: 383-392.

List of Lower Taxa