Gymnocalycium parvulum subsp. amoenum Gymnocalycium parvulum subsp. huettneri Gymnocalycium quehlianum var. calochlorum Gymnocalycium amoenum Gymnocalycium calochlorum var. proliferum Gymnocalycium parvulum var. amoenum Gymnocalycium proliferum Gymnocalycium proliferum var. calochlorum Gymnocalycium parvulum subsp. agnesiae Echinocactus calochlorus Echinocactus prolifer
World Flora Online, http://www.worldfloraonline.org/, accessed June 20, 2024