We use high-speed video imaging (1,000 to 10,000fps) to record the remarkably fast opening of the flowers of Cornus canadensis, which is also known as bunchberry or Canada dogwood. These amazing flowers can bloom in under 0.4 ms--a time shorter than it takes for a bullet to travel the length of a rifle barrel. To our knowledge this is the fastest flower on earth. Pollen is accelerated at 24,000 m/s², which is 2400 times the acceleration of gravity and 800 times that experienced by astronauts during liftoff. Pollen leaves the plant with an initial velocity of more than 4 m/s and is propelled an impressive 2.5 cm into the air, over ten times the height of the flower.

Explosive flowering enhances insect pollination in two ways. First explosive flowering reduces the amount of pollen eaten by the insects because the pollen spray from the explosion disperses the pollen on insects' bodies and the high speed of the pollen imbeds it deep in the insects' hairs where it is less likely to be gathered and eaten. Second, explosive flowering limits pollinators to insects heavy enough to trigger the flower. Large flies, bumblebees and beetles are large enough to trigger flowers and move rapidly between inflorescences, whereas ants and small flies, which often stay on one inflorescence, cannot trigger the flowers.

In the absence of insect pollinators, explosive flowering may also allow for wind pollination.

Click on the links above to learn more about this remarkable plant and to see samples of our high-speed videos. This work first appeared in the 12 May edition of the journal Nature, and can be found here.

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All images and video copyright 2005. All rights reserved