Cereus or Columnar is a genus of cacti (family Cactaceae) including roughly 33 species of large columnar cacti from South America. The name is derived from Greek (κηρός) and Latin words meaning "wax" or "torch". The genus Columnar, or Cereus was one of the first cactus genera to be described; the circumscription varies depending on the authority. Any cactus with a very elongated body, including columnar growth cacti and epiphytic cacti.