Edwards et al. (2005) have a paper in Nature documenting an extremely speedy plant: the flowers of the bunchberry dogwood (Cornus canadensis) open in less than half a millisecond; as the flower explodes open, its stamens act like a trebuchet, flinging pollen into the air.
Nature's website has a few snazzy slow-motion videos (10,000 fps) of the flower opening in its supplementary information section (free), along with two of the paper's figures (also free).
Edwards J, D Whitaker, S Klionsky, and MJ Laskowski. 2005. Botany: A record-breaking pollen catapult. Nature 435 164 | doi: 10.1038/435164a