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Report of
Science at Williams




The blooming of a bunchberry flower (Cornus canadensis) filmed at 10,000 fps.

The flowers of the bunchberry dogwood (Cornus canadensis) open explosively to propel pollen from stamens that are designed like miniature trebuchet catapults. This nine-image sequence is from a high-speed video (10,000fps) and shows the explosive flowering over one millisecond (the time is indicated in the upper left-hand corner). The first frame shows a closed flower; the filaments of the pollen-bearing anthers are bent in the bud and extend from between the petals. Within 0.2 milliseconds the petals move out of the way of the stamens and by 0.3 milliseconds the pollen has been catapulted upwards at accelerations up to 24,000 ± 6,000 m/s2 and speeds of 3.1± 0.5 m/s. The blur in each picture represents the distance moved in 0.1ms. Pollen is launched to an impressive height of 2.5 cm, which is more than ten times the height of the flower. Explosive flowering in bunchberry may increase successful cross-pollinations by enhancing insect pollination and allowing for pollination by wind. The Guinness Book of World Records has officially listed bunchberry as the fastest opening flower.
This research, published in the 12 May issue of Nature, is an interdisciplinary collaborative project led by Professor Joan Edwards of the Biology Department, Professor Dwight Whitaker of the Physics Department, and Professor Marta Laskowski (Biology Department, Oberlin College) with the help of students Sarah Klionsky ’03, Alejandro Acosta ’05, Ellen Crocker ’06, and Don Mitchell ’06.
Photo Credit: Alejandro Acosta, Joan Edwards, Marta Laskowski, and Dwight Whitaker

The Science Executive Committee wishes to express its gratitude to the extensive efforts of all the science departmental executive assistants in preparing contributions for this publication, and to Kate Fletcher, administrative assistant at the Science Center, for assembling this material in its final form.

Editor: Dr. Bryce Babcock

This document is printed on recycled paper.
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