Fasciation is a genetic mutation of a plant's growing tip, and it can affect the stem, flowers, or fruits.
Sometimes, the results aren't very dramatic. For example, the growing shoots may end up flattened, splayed apart, or may seem to be made up of several stems fused into one.
But other times, the effects are extremely eye-catching, such as grossly oversized flowers with a weirdly grotesque look — the closer to the ground that fasciation happens, the more exaggerated its effects tend to be.
