Pachycereus (A.Berger) Britton & Rose in Contr. U.S. Natl. Herb. 12: 420. 1909 sec. Franco-Estrada & al. 2021



Phylogenetic studies based on morphological and molecular data show consistently that Pachycereus s.str. is a monophyletic group with five species (Arias & al. 2003; Arias & Terrazas 2006, 2009; Arias & al. 2012; Franco-Estrada 2021). Other species previously considered in Pachycereus (Buxbaum 1961; Gibson & Horak 1978; Anderson 2001; Hunt 2006; Nyffeler & Eggli 2010) have been transferred to Lemaireocereus, Lophocereus, and Cephalocereus. Pachycereus s.str. includes tree-like species, interareolar grooves on the stems, abundant trichomes on flower, and flexible spines on the fruit.
The phylogenetic position of the two monotypic genera Backebergia and Pterocereus was recently clarified by Franco-Estrada & al. (2021). Pterocereus (P. gaumeri) was resolved as sister to Lophocereus (1 PP) while Backebergia (B. militaris) was resolved as sister to the clade of Marshallocereus + (Pterocereus + Lophocereus), both placements were maximally supported by Bayesian Inference (1 PP), justifying their generic status separate from Pachycereus.A
A. Sanchez, D. & Arias, S. 2022: Updates to the Cactaceae species-level checklist for the genera Peniocereus, Pachycereus, Backebergia and Pterocereus. – Published online at