RT Journal Article SR Electronic T1 The Fern Sporangium: A Unique Catapult JF Science JO Science FD American Association for the Advancement of Science SP 1322 OP 1322 DO 10.1126/science.1215985 VO 335 IS 6074 A1 Noblin, X. A1 Rojas, N. O. A1 Westbrook, J. A1 Llorens, C. A1 Argentina, M. A1 Dumais, J. YR 2012 UL http://science.sciencemag.org/content/335/6074/1322.abstract AB Various plants and fungi have evolved ingenious devices to disperse their spores. One such mechanism is the cavitation-triggered catapult of fern sporangia. The spherical sporangia enclosing the spores are equipped with a row of 12 to 13 specialized cells, the annulus. When dehydrating, these cells induce a dramatic change of curvature in the sporangium, which is released abruptly after the cavitation of the annulus cells. The entire ejection process is reminiscent of human-made catapults with one notable exception: The sporangia lack the crossbar that arrests the catapult arm in its returning motion. We show that much of the sophistication and efficiency of the ejection mechanism lies in the two very different time scales associated with the annulus closure.