Plant Ballistics: Mountain Laurel’s Explosive Pollen Bullets

Mountain Laurel, Terrys Fork, Virginia

The intricate design of the Mountain Laurel (Kalmia latifolia) was a marvel for me in 1970 when I was a student on a field trip to the Smokies from Auburn University. Systematic Botany was a wake-up call to a budding zoologist who should not think there was little to learn from fixed, do-nothing greenery. I declared a botany minor after that field trip.

Laurel’s ten spring-tethered anthers (the pollen package) are arranged radially around the receptive stigma–the female part–in the very center of the flower.

A visiting insect would typically land on the disk and walk around the center in search of high-calorie nectar. And zap! the tension in the tethering “filaments” would shoot pollen onto the bee who would fly off with pollen from Plant A to deposit it on the female parts of flowers on Plant B.

But wait. Is this REALLY the strategy and method Kalmia uses to maintain genetic vigor? High-speed filming has revealed some answers.

Another similar method is used by a dogwood called Bunchberry–but the anthers additionally are able to swivel at the end of the filaments–creating more of a trebuchet force than a simple catapult like Kalmia.

Watch this short video of explosive Bunchberry pollen at 10k frames per second.

Author: fred

Fred First holds masters degrees in Vertebrate Zoology and physical therapy, and has been a biology teacher and physical therapist by profession. He moved to southwest Virginia in 1975 and to Floyd County in 1997. He maintains a daily photo-blog, broadcasts essays on the Roanoke NPR station, and contributes regular columns for the Floyd Press and Roanoke's Star Sentinel. His two non-fiction books, Slow Road Home and his recent What We Hold in Our Hands, celebrate the riches that we possess in our families and communities, our natural bounty, social capital and Appalachian cultures old and new. He has served on the Jacksonville Center Board of Directors and is newly active in the Sustain Floyd organization. He lives in northeastern Floyd County on the headwaters of the Roanoke River.

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