[Holo]type is Palmer 107, USNH 572337 (explicitly cited by sheet number in protologue). Other US specimens (in box, USNH 3050014) are labeled as Palmer 108, possibly mis-numbered [Another US sheet labeled as Palmer 108 is Mammillaria heyderi.] are dubiously types but may be uncited original material, possibly collected from cultivation at a later date (labeled with with greenhouse acc. no. 07.108).