Pterocactus australis var. arnoldianus Backeb. in Cact. Succ. J. (Los Angeles) 23: 14. 1951 Pterocactus australis var. arnoldianus Backeb. in Cact. Succ. J. (Los Angeles) 23: 14. 1951Taxon for this namePterocactus australis var. arnoldianus Backeb.
