DistributionPantropical, with twenty species.

Habit

Annual or perennial herbs, scandent or erect shrubs.

Leaves

Leaves opposite, blades narrowly obovate to linear-lanceolate, ovate, triplinerved, unlobed, trilobed or pinnately lobed. 

Flowers

Capitula in terminal,open paniculiform cymes, rarely solitary, discoid or radiate. Involucres campanulate to hemispherical, phyllaries in 1-2series, subequal. Receptacles convex. Ray florets pistillate but sterile or neuter, corollas yellow. Disc florets bisexual, corollas yellow or white, without fibres embedding the vascular strands, sometimes with a few sclerified cells along vascular strands; anthers black, appendages with glandular trichomes; style arms tapered to acute, apices shallowly papillose. 

Fruit

Ray cypselae obcompressed, triquetrous to quadrate, obovate to obpyramidal, black, apices truncate, sometimes winged on angles of cypsela, glabrescent. Disc cypselae compressed, obconical, somewhat quadrangular, otherwise as ray cypselae. Pappus of several caducous awns.

Chromosomes

x = 15, 16