According to the botanists, fasciation or cristation is an abnormal development of an apical meristem characterized by indeterminate proliferative growth. That is, a plant becomes crested when its apex develops laterally from a linear meristem rather than a single point.
In simple translation, crested plants are freaks and only mother Nature could be capable of creating such ugly-pretty mutants because no one has ever produced this kind of effect artificially. Some plant collectors consider these crested plants as real living sculptures because they look very outstanding when potted and certainly attract a lot of attention, just like my Cleistocactus winteri forma cristata in the photo above. I often ask what could have caused the cristation of my cleistocactus. Could it be a natural mutation? Is it possible that insects or disease have damaged its growth point?
Despite their weird appearance, crested cacti are easy to cultivate. Occasionally, I trim any normal shoots off the cactus to help the crested form grow better and truer to form. However, sometimes these normal shoots can crest again after some normal growth. To keep the plant and the cuttings from rotting, I always bear in mind to place them in a dry area for at least a week or preferably two weeks.