Generic characters
The Tehuacán-Cuicatlán flora recognizes Lemaireocereus by the combination of rounded ribs, flowers developing at branch ends, and hairs and bristles on flowers and fruits. Fruits contain red or purple pulp and open irregularly. This combination is more diagnostic than columnar habit alone. [Arias et al. 2012]
Phylogenetic distinctness
The 2025 phylogenomic study corroborates the distinct position of Lemaireocereus relative to Pachycereus and other North American columnar cacti. The authors relate this result to earlier morphological and molecular analyses. The accepted genus unites two geographically separated species, whereas many other historical combinations under Lemaireocereus now belong to different genera. [de Vos et al. 2025] [2-WWW]
The historical dumortieri name
POWO treats Lemaireocereus dumortieri as a synonym of Isolatocereus dumortieri. Papers using that historical name concern the biology of Isolatocereus and link to its account. The name does not add another accepted species to Lemaireocereus. [2-WWW] [2-WWW]