A biological mechanism not in the textbooks

 Here’s one method for dispersing cattail seeds you don’t find in the textbooks: The head of a cattail was broken off by the 20 mph north wind and was skidding across the lawn near the university.

The enormous dog that lives at my house picked up the reed. A gust of wind hit the cattail spike, and seeds with their parachutes flew everywhere. The dog, astonished, looked at the equally astonished human at the other end of the leash. The dog gave the stalk a shake. Seeds flew everywhere.

The wind chill at the time was a degree above freezing.

This is what passes for winter in South Texas. We are spreading seeds like mad.

Seeds are dispersed by wind and water. They stick, as burrs, in the coats of coyotes and on the feet of ducks. So much we are told. But that account is incomplete. It overlooks the tiny but indisputable presence of another factor in the dispersal of seeds: the psychological proclivity for play among dogs — and boys.

A couple of days ago, I saw a little boy tugging at a cattail spike. I could see the clouds of seeds flying on the wind. From a distance, I thought I was seeing one of those machines that make soap bubbles.

If we understood the world, we would understand how seeds are dispersed. And that theory would include forces such as wind and water. But it also would include a note on what it is in dogs and boys that makes them want to play with a cattail spike.