Human Flower Project

Friday, September 18, 2009

Plants with Wheels

Noxious intruder,  romantic emblem, or prom decoration? This Russian immigrant has become synonymous with America’s Old West.

Uranium collectors, “lonely but free…”
Photo: Rob Lee

By James H. Wandersee and Renee M. Clary
EarthScholars™ Research Group

“Bloom where you’re planted” is the motto of many species, but plants actually spread—and bloom—far beyond where they first grow using a wide variety of strategies, including wind power. 

Some aeolian plants send their seeds off in gusts to seek their fortunes via cottony tufts (cattails) and parachutes (dandelions), while others employ gliders (climbing gourds) and helicopters (maple trees). Most wind-powered plants launch such “botanical aircraft” to disperse their seeds, but some plants actually make the scattering trip themselves.  We’re talking about tumbleweeds.

Tumbleweeds are globe-like, senescent (aged, dried) plants whose stems, at maturity, separate from their root systems during windy weather. Before these bushes mature, most of them are green and bushy with tiny light pink flowers, turning gray and stiff when they are ready to tumble. Then they are pushed across the terrain by the prevailing winds, scattering thousands of seeds (up to 250,000 per plant!) across the landscape as they roll.

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