Cereus c.v. monstrose – Each is a clone of a virus-ridden parent. Many variable parents give us many variable monstroses.
In case that wasn’t entirely clear, what’s going on is a perfectly normal smooth vertical cactus like the Cereus peruvianus from Peru catches a virus and the resultant form is known as a “monstrose.” Sometimes, you get a crested plant, but in this instance, you get this monstrous form of all these bumpies up and down the trunk. Good stuff.
Now, if you let it go to seed, generally the virus will not be transmitted to the babies, and the plant will revert to its original form (which it can do anyway). So you propagate these exclusively by cuttings. This means that any individual variations in the monstrosenesses will be carried identically by the cloned babies. And any variations between plants means they came from different virused parents.
Is that more clear?
Now if you would like to know more you can find it here.
Many cacti and succulents grow… with an apical meristem, the dominant bud at the very top that contributes to its pyramidal form… This gives them their symmetrical shapes. Occasionally something happens to that meristem and it mutates. One growth point turns into many, forcing the top of the plant to fans out into a series of mini-points. The result is that the top of a pointed cactus produces a crest that can look very much like a rooster comb.
In other cases, the mutation may occur throughout the plant, not just at the top. Growth points originate all over the stem or branches causing very irregular growth. The result is a monstrosity, and while the plant remains the same species, it may bear very little resemblance to its kin.
Oddly enough an occasional crest, or monstrose, branch will appear on a normal plant. Sometimes a monstrose plant will revert to normal growth. It’s a genetic crap-shoot and Mother Nature holds the dice.