Baker M., Cloud-Hughes M. A., Reassessment of subspecific taxa within Pediocactus peeblesianus (Cactaceae) by multivariate analysis of morphological characters, Journal of the Botanical Research Institute of Texas, 2022, 16(1):297-315, doi: 10.17348/jbrit.v16.i1.1234
An analysis of seventeen morphological traits in 233 Pediocactus peeblesianus and 90 P. sileri plants. The P. peeblesianus groups studied overlapped widely, and some variation depended on stem size. The authors reject the former subspecies division and consider retention of juvenile traits by small reproductive plants. Pediocactus sileri forms a distinct comparison group.