Rooksbya euphorbioides var. olfersii (Salm-Dyck) Backeb., Cactaceae 4: 2170. 1960 Rooksbya euphorbioides var. olfersii (Salm-Dyck) Backeb., Cactaceae 4: 2170. 1960is new combination for Cereus olfersii Salm-Dyck, Hort. Dyck.: 335. 1834Taxon for this nameRooksbya euphorbioides var. olfersii (Salm-Dyck) Backeb.