Cereus chalybaeus
 Cereus chalybaeus is a cactus from the genus Cereus a genus consisting of about 25 species of tree-like cacti. Cereus chalybaeus is a columnar cactus with 5-6 ribbs. It is few-branched and often purple tinged. It has spines that at first are red but with age turn black. In summer it bears funnel-shaped flowers which can be up to 8 inches long. The inner petals are white and the outer petals are either purple or red.