Ageratina

Perennial herbs or shrubs. Leaves opposite, rarely subopposite or alternate, petiolate; margins entire, crenate, dentate or serrate. Capitula campanulate, discoid, usually in dense corymbs, sometimes solitary; involucral bracts 2(–3) seriate, ± equal, lanceolate to linear, herbaceous; receptacle convex, sometimes with minute scattered hairs. Florets white or purple, 4- or 5-lobed, usually with narrow basal tube and campanulate limb; outer surface of lobes glabrous or glandular and hairy; inner surface papillose; anthers obtuse at base, with an ovate or oblong apical appendage; style bases sometimes enlarged, glabrous; style branches linear, papillose. Cypselas fusiform or cylindric, usually 5-ribbed, with setae and/or glands; pappus of 5–40 barbellate to plumose bristles, often deciduous.