Ferocactus orcuttii Ferocactus viridescens var. littoralis Ferocactus viridescens subsp. littoralis Ferocactus viridescens var. orcuttii Ferocactus viridescens var. viridescens Echinocactus viridescens Melocactus viridescens Echinocactus cylindraceus Echinocactus limitus Echinocactus orcuttii Echinocactus viridescens Ferocactus viridescens subsp. orcuttii
World Flora Online, http://www.worldfloraonline.org/, accessed June 20, 2024