Gymnocalycium reductum subsp. reductum sec. Charles 2009
- =Cactus nobilis Haw., Syn. Pl. Succ.: 174. 1812, nom. illeg., syn. sec. Charles 2009
- ≡Echinocactus gibbosus var. nobilis (Haw.) K.Schum., Nat. Pflanzenfam. 3, Abt. 6a: 188. 1894 syn. sec. Charles 2009
- ≡Echinocactus gibbosus f. nobilis (Haw.) Schelle, Handb. Kakteenkult.: 186. 1907 syn. sec. Charles 2009
- ≡Echinocactus gibbosus var. nobilis Monv. ex Lem., Cact. Gen. Sp. Nov.: 91. 1839 syn. sec. Charles 2009
- =Echinocactus mackieanus Hook. in Bot. Mag. 64: t. 3561. 1837 syn. sec. Charles 2009
- ≡Gymnocalycium mackieanum (Hook.) Metzing, Mereg. & R.Kiesling in Allionia 33: 209. 1995 syn. sec. Charles 2009
- =Echinocactus leucodictyus Salm-Dyck, Cact. Hort. Dyck., ed. 1849: 34, 171. 1850 syn. sec. Metzing 2021
- ≡Echinocactus gibbosus var. leucodictyus Salm-Dyck, Cact. Hort. Dyck., ed. 1849: 34, 171. 1850 syn. sec. Metzing 2021
- ≡Echinocactus gibbosus var. leucodictyus (Salm-Dyck) Rümpler, Handb. Cacteenk., ed. 2: 583. 1886 syn. sec. Metzing 2021
- ≡Echinocactus gibbosus f. leucodictyus (Salm-Dyck) Schelle, Handb. Kakteenkult.: 186. 1907 syn. sec. Metzing 2021
- =Echinocactus gibbosus var. leucacanthus Rümpler, Handb. Cacteenk., ed. 2: 583. 1886 syn. sec. Metzing 2021
- ≡Echinocactus gibbosus f. leucacanthus (Rümpler) Schelle, Handb. Kakteenkult.: 186. 1907 syn. sec. Metzing 2021
- =Echinocactus platensis Speg., Contr. Fl. Sierra Vent.: 28. 1896 syn. sec. Metzing 2021
- ≡Echinocactus gibbosus var. platensis (Speg.) Speg. in Anales Mus. Nac. Buenos Aires, ser. 3, 2: 8. 1903 syn. sec. Metzing 2021
- ≡Gymnocalycium platense (Speg.) Britton & Rose, Cactaceae 3: 163. 1922 syn. sec. Metzing 2021
- ≡Echinocactus gibbosus var. platensis (Speg.) J.G.Lamb. in Repert. Pl. Succ. 42: 5. 1992 syn. sec. Metzing 2021
- ≡Gymnocalycium reductum var. platense (Speg.) R.Kiesling in Darwiniana 45: 237. 2007 syn. sec. Metzing 2021
- =Echinocactus gibbosus var. ventanicola Speg. in Anales Mus. Nac. Buenos Aires, ser. 3, 2: 7. 1903 syn. sec. Metzing 2021
- ≡Gymnocalycium platense var. ventanicola (Speg.) R.Kiesling in Darwiniana 24: 441. 1982 syn. sec. Metzing 2021