The spores of one fern are launched from the sporangium using a mechanism based on surface tension and evaporation.

“A mechanism based on the surface tension of water is used by a fern that forcibly discharges its spores from the sporangium–evaporation decreases the volume of water and increases the surface curvature in a series of cuplike dead cells until the sustainable cohesion is exceeded; water then vaporizes and tension is relieved by a movement analogous to that involved in throwing a spear (Steward 1968).” (Vogel 2003:449)

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Last Updated August 18, 2016