Cephalanthus is a genus of flowering plants in the madder family, Rubiaceae. Different authorities accept between six and 15 species, which are commonly known as Buttonbushes. Cephalanthus occidentalis is native to the eastern United States and Canada. It normally grows in wetter habitats, where they occur as shrubs or small trees growing to 2.5–5m (7–15 ft) tall. The leaves are simple, arranged in opposite pairs or whorls of three. The flowers form a dense globularinflorescence.
Cephalanthus was named by Linnaeus in Species Plantarum in 1753. The generic name is derived from the Ancient Greek words κέφαλος (kephalos), meaning "head", and ἄνθος (anthos), meaning "flower."