Pachycereus

Pachycereus is a genus of large cacti native to Central America and Mexico. They form large shrubs or small trees up to 15 m tall, with stout stems up to 1 m in diameter. Pachycereus comes from the ancient Greek παχύς (pachys) meaning "thick" and the Latin cereus meaning "torch".

Species
, Plants of the World Online accepted six species: P. pringlei is the tallest cactus species in the world, with a maximum recorded height of 19.2 m.

Synonymy
These genera have been brought into synonymy with Pachycereus by some sources, although, not by Plants of the World Online:
 * Lemaireocereus Britton & Rose
 * Marginatocereus (Backeb.) Backeb.

Species that may be placed in Pachycereus include:
 * Pachycereus hollianus (F.A.C.Weber ex J.M.Coult.) Buxb. = Lemaireocereus hollianus
 * Pachycereus lepidanthus (Eichlam) Britton & Rose = Lemaireocereus lepidanthus
 * Pachycereus militaris (Audot) D.R.Hunt = Mitrocereus militaris