Peniocereus (A.Berger) Britton & Rose in Contr. U.S. Natl. Herb. 12: 428. 1909 sec. Arias & al. 2005



The generic circumscription of Peniocereus was revised based on the molecular phylogenetic study of Arias & al. (2005). Their study based on plastid trnL-F and rpl16 found Peniocereus polyphyletic, its species resolved in three lineages. Peniocereus subg. Pseudoacanthocereus was found to be nested in Acanthocereus, yet both were also paraphyletic. For a classification reflecting these relationships, Peniocereus subg. Pseudoacanthocereus was transferred to Acanthocereus (Lodé 2013; Korotkova & al. 2017). The other major Peniocereus clade found by Arias & al. (2005) corresponds to Peniocereus subg. Peniocereus.
Peniocereus serpentinus, the type species of the earlier-proposed genus Nyctocereus was resolved as a separate lineage reinstating it as a monotypic genus Arias & al. (2005).
Phylogenetic relationships of Peniocereus and its relatives in the Pachycereinae were revisited by Franco-Estrada & a. (2021) using sequences from 5 plastid markers. This study confirmed the circumscription of Peniocereus with 7 species, Pachycereus with 5 species and provided well-supported evidence for the placement of Backebergia and Pterocereus as monotypic genera within the Pachycereinae.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