Sport in Botany defined by Wikipedia :

In botany, a sport or bud sport, traditionally called lusus,^[2] is a part of a plant that shows morphological differences from the rest of the plant. Sports may differ by foliage shape or color, flowers, fruit, or branch structure. The cause is generally thought to be a chance genetic mutation.^[3]

I saw a sport once. Eight or nine twigs on a forsythia bush, each fused to the next, like a pan pipe. It still had leaves and flowers. I was reading sci-fi books at the time, I was only young and found the strange formation almost creepy. I cut the sport off the bush and it never grew back. But I always remembered this sporting image!