Cephalanthus occidentalis, or Buttonbush is native to the eastern United States and Canada. It is in the madder family, Rubiaceae. 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 globular inflorescence.
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."