Vines – Wrapping Counter Clock-Wise?

Q: Every vine that I’ve noticed winds around the support counter clock-wise. Do they all do that? In the southern hemisphere, do the vines all wind clockwise?

A: Vines twine because as they grow longer they also circumnutate (bend in various directions) during the day. When the vine touches a surface, the cells opposite the touch point elongate, causing the vine to begin wrapping around the vertical item. It’s not true that vines in one hemisphere wrap in one direction and those in the other hemisphere wrap in the other direction. Further, not all vines in our hemisphere wrap in one direction: some species tend to wrap clockwise and some counterclockwise. It’s even true that vines can reverse direction and wrap in the opposite direction if something interferes with their initial motion.