Gutiérrez-Flores C., León-de la Luz J. L., García-De León F. J., Cota-Sánchez J. H., Variation in chromosome number and breeding systems: implications for diversification in Pachycereus pringlei (Cactaceae), Comparative Cytogenetics, 2018, 12(1):61-82, doi: 10.3897/CompCytogen.v12i1.21554
The cytological study documents diploid and tetraploid populations of Pachycereus pringlei. It compares chromosome number, geography, floral traits and breeding systems. Associations between ploidy and reproductive variation support evolutionary hypotheses that require further crossing experiments.