Synonyms: Echinocactus platensis var. parvulus (homotypic); Echinocactus platensis var. terweemeanum (homotypic); Gymnocalycium amoenum; Gymnocalycium berchtii; Gymnocalycium berchtii var. nataliae; Gymnocalycium nataliae; Gymnocalycium parvulum agnesiae; Gymnocalycium parvulum amoenum; Gymnocalycium parvulum huettneri; Gymnocalycium parvulum var. amoenum; Gymnocalycium parvulum var. walteri; Gymnocalycium platense var. parvulum (homotypic); Gymnocalycium poeschlii; Gymnocalycium quehlianum var. terweemeanum; Gymnocalycium terweemeanum; Gymnocalycium walteri