Cid R., Palomino G., Cytotypes and Meiotic Behavior in Mexican Populations of Myrtillocactus geometrizans var. geometrizans (Cactaceae), Cytologia, 1996, 61(3):343-348, doi: 10.1508/cytologia.61.343
The cytogenetic analysis compares plants from three populations in Hidalgo, Puebla and Querétaro. All examined plants were diploid with 22 chromosomes, and 11 bivalents were observed during meiosis. The Querétaro population differed in having smaller chromosomes and satellites on two pairs, whereas the other populations had satellites on one pair. The study documents karyotype variation within the species.