As a performance piece, the pageant of botanic superlatives is more like a tableau vivant than any Olympic games; most competitions of time are measured in days and centuries, and the actors are rewarded for endurance and form. On this stage, however, there is the frenetic performance of a certain contestant: Launching pollen into the air in a third of the time it takes a bullet to leave a rifle barrel, it is a superlative example of botanic ballistics, engineering, and reproductive design. It is the Bunchberry dogwood (Cornus canadensis), and its first-place sash will read "Fastest Flower."
The blossoms of the Bunchberry dogwood are regarded as the world's fastest-opening flowers, opening in less than half a millisecond. As they develop, each flower's four petals are joined at the tip, creating a capsule that encases the four stamens with their four pollen-laden anthers. One petal is affixed with a tiny "finger," poised to catalyze an explosive release when the flower is mature. And so, harnessing the power of physics (elastic energy that builds within the bud) and design (pollen poised to disseminate), the Bunchberry dogwood waits for a bumblebee to alight on its trigger mechanism: an appealing landing pad for visiting pollinators, and a necessary interaction for the self-sterile flower to reproduce.
Cornus canadensis (left to right): fused petal capsule, petal trigger, and pollen release. Photo credit: Joan Edwards and Dwight Whitaker, Williams College
And so the cluster of tiny fireworks is set into motion: The bee descends, the trigger is released, the petals spring backwards, and a cloud of pollen is flung at the pollinator. And the judges record the numbers: 24,000 m/s², the rate at which pollen is accelerated; 4 m/s, the initial velocity at which it is launched; and 2.5 cm, the height at which it is propelled into the air.
Beyond our pageant stage, the California-native Bunchberry dogwood can also be found along the fringes of damp woods, on tree stumps, and many mossy landscapes in Northern China, far-eastern Russia, and Japan.
Anna Laurent is a writer and producer of educational botanical media. Photographs from her forthcoming field guide to Los Angeles are available for exhibition and purchase at the author's shop.