Excerpts from Jim Conrad's
Naturalist Newsletter

from the June 20, 2010 Newsletter issued from Hacienda Chichen Resort beside Chichén Itzá ruins, central Yucatán, MÉXICO
CLOCKWISE & COUNTERCLOCKWISE TENDRILS

On my first full-fledged botanical expedition, in 1974 or thereabouts, on an overnight Varig flight from New York to Brazil, I knew exactly the first thing I wanted to do upon passing customs in Río de Janeiro: I wanted to make a beeline into a bathroom and flush a commode to see if, because of the Coriolis Effect, the water drained out clockwise, as it's supposed to north of the Equator, or counterclockwise, as I'd always read it does south of the Equator. Result: it drained straight down without spiraling. Eventually I found that some flushes south of the Equator went "right," others "left," so I was a little disappointed. There's an in-depth look at this whole issue at http://www.snopes.com/science/coriolis.asp.

Despite those disappointing results, wherever in the world I've been since then, I've halfheartedly tried to figure out whether vines and their tendrils take the Coriolis Effect into account. Maybe because during most of my travels I've been too hot or too cold, too hungry or too sick, too lost or too sleepy to think straight, somehow my whole life has passed without my figuring it out. Therefore, this week in the organic garden I was transfixed when I saw what's shown below:

cucumber tendril

That's a cucumber tendril. It originated on a vine beyond the picture to the left, coiling clockwise, then it changed direction and began coiling counterclockwise, then after three cycles it changed directions once again to clockwise, and by golly it looks like that as it's wrapping itself around the vertical pole, it's doing so counterclockwise.

On the Internet, there are answers to questions such as what's going on with cucumber vine tendrils.

The fast answer is that science doesn't really know what causes plants and their tendrils to wrap one way or another around a pole. Most vines twine counterclockwise, though about 10% go clockwise. Some do it both ways. The twining direction of vines is not dependent on whether the plant lives north or south of the Equator. Twining direction is genetic, and some species go one way while others go the other.

And cucumber vines, they say, and as we've seen ourselves, can have tendrils coiling in either direction.