Vegetative stems and the flowering zone
On mature stem portions, the areoles produce longer, more flexible spines. Their concentration gives the flowering zone a bristly appearance. In Lophocereus schottii this portion is termed a pseudocephalium because it remains continuous with the rest of the stem. Flowers develop among the spines while some shorter stems of the same plant remain vegetative. [Martorell et al. 2006] [Jones 1934]
Two species and different bodies of evidence
Lophocereus gatesii is distinguished by numerous sharply defined ribs documented in its protologue. Lophocereus schottii has become a study system for clonality, the division of stem functions and insect interactions. The pollination and sterol experiments used identified Lophocereus schottii material. Their conclusions retain this species-level scope. [Jones 1934] [Parker and Hamrick 1992] [Martorell et al. 2006] [Fleming and Holland 1998] [Heed and Kircher 1965]
Generic boundaries in the current classification
Marginatocereus marginatus is currently accepted in the separate genus Marginatocereus. Lophocereus marginatus and Pachycereus marginatus refer to that same species. The 2025 phylogenomic study places Lophocereus and Marginatocereus within the North American columnar cactus lineage while retaining them as distinct genera. [2-WWW] [2-WWW] [de Vos et al. 2025]