Description from Flora of China
Shrubs or herbs, ± aromatic. Leaves alternate, simple. Synflorescences elongate panicles or flat-topped. Capitula many flowered, disciform, usually numerous. Phyllaries imbricate. Marginal florets numerous, in several rows, filiform, female, fertile; achenes 4- or 5-angled, longitudinally grooved. Central florets far fewer than marginal ones, tubular, bisexual, functionally male; anthers obtuse at apex, tailed at base. Style entire, sometimes divided, style branches with obtuse sweeping hairs reaching below furcation; achenes often indistinct or vestigial as a small ring of basal sclerenchymatous cells of carpopodium. Pappus of basally connate, barbellate bristles in 1 row. x = 10.
About 80 species: Africa, SE Asia, Australia, Caribbean, North and South America, Pacific islands; five species (two introduced) in China.