- A native to Central America, this plant grows in disturbed areas in full sunlight on heavy soils retaining above average moisture. It usually occurs as a common weed of roadsides, creek banks, cultivated headlands and rundown pastures.
- An erect aromatic robust herb with several quadrangular branching stems 60-250 cm high.
- Leaves are bright green, opposite and widely spaced on stems, up to 12 cm long, 5 cm wide, tapering at both ends, margins irregularly toothed.
- Small white flowers in compact globular heads about 1.5 cm diameter on stalks to 5 cm long in leaf axils.
- Fruit is a 4-lobed capsule divided into 4 seed-like nutlets, which when ripe, rattle when the plant is shaken.