Ageratum L.
Annual or perennial herbs or shrubs. Lvs opposite, petiolate, simple, usually toothed. Infl. a corymb, usually dense. Involucral bracts in 2-(3) rows, usually subequal, mostly chartaceous. Receptacle conic; scales usually 0. Corolla tubular. Style base not swollen. Achenes ellipsoid-cylindric to obpyramidal, 5-angled, hairy; pappus usually of few free or united scales, sometimes reduced to a corona or 0.
43 spp., tropical America. Naturalised sp. 1.
