Mammillaria vetula subsp. gracilis (Pfeiff.) D.R. Hunt, Mammillaria Postscripts 6: 6. 1997 sec. Hunt 2016
- ≡Mammillaria gracilis Pfeiff. in Allg. Gartenzeitung 6: 275. 1838 syn. sec. Hunt & al. 2006
- =Mammillaria gracilis var. pulchella Salm-Dyck, Cact. hort. dyck., ed. 3: 103. 1850 syn. sec. Guzmán & al. 2003
- =Cactus gracilis (Pfeiff.) Kuntze, Rev. Gen. Pl. 1: 260. 1891 syn. sec. Guzmán & al. 2003
- =Mammillaria fragilis Salm-Dyck ex K. Brandegee in Zoe 5: 9. 1900 syn. sec. Guzmán & al. 2003
- =Neomammillaria fragilis (Salm-Dyck) Britton & Rose, Cactaceae (Britton & Rose) 4: 132. 1923 syn. sec. Guzmán & al. 2003
- =Mammillaria gracilis var. fragilis (Salm-Dyck ex K. Brandegee) A. Berger, Kakteen (Berger): 304. 1929 syn. sec. Guzmán & al. 2003
- =Escobariopsis gracilis (Pfeiff.) Doweld in Sukkulenty 3: 40. 2000 syn. sec. Guzmán & al. 2003
- =Krainzia gracilis (Pfeiff.) Doweld in Novosti Syst. Vyssh. Rast. 33: 169. 2001 syn. sec. Hunt & al. 2006