Annual or perennial herbs or shrubs (rarely trees) without latex; leaves alternate or op- posite (rarely whorled); heads radiate or discoid, small to medium-sized; involucre cylindric to hemispheric, bracts 1–8-seriate without hyaline or scabrous margins; recep- tacle usually paleate; ray florets, if present, pistillate, co- rollas highly reduced or well-developed, yellow to white, tubular or strap-shaped, usually 3-lobed; disc corollas yellow, tubular, usually with five lobes of equal size not longer than wide; anther apical appendage ovate to del- tate, thecae usually blackened, without spurs (ecalcarate) and without tails (ecaudate); pollen echinate and spheri- cal; styles slender, apices more or less acute with terminal tuft of hairs, remainder of style glabrous or papillose, at maturity style branches recurving; achenes usually not flattened, walls with phytomelanin layer; pappus absent or of scales, awns, or bristles, sometimes coroniform.

Diagnostic Features

Stems fistulose and rooting at nodes or not; paleae tightly enfolding achenes in aquatic or marsh-dwelling taxa; receptacle usually paleate; an- thers usually blackened; achenes blackened.

Geographic distribution

Mainly Neotropics (few species in Pale- otropics).