Echinocactus horizonthalonius var. nicholii
Echinocactus horizonthalonius var. nicholii, Cacti Ariz., ed. 3: 23. 1969 sec. Hernández & Gómez-Hinostrosa 20111 wfo-0000660534
- ≡Meyerocactus horizonthalonius subsp. nicholii in Sukkulenty 1(2): 27. 1999 syn. sec. Guzmán Cruz & al. 20032 wfo-0001286156
- ≡Echinocactus horizonthalonius subsp. nicholii in Cactaceae Syst. Init. 16: 17. 2003 syn. sec. ??? wfo-0000660535