Certain plants exude organic sulfides through their roots. In their pure state, many of these sulfides have bacteriostatic, fungicidal, nematicidal, and insecticidal properties. It is not known whether plants emit sufficient amounts of the sulfides to have these effects in natural systems. The P.I.'s will investigate the phylogenetic distribution of these compounds and determine whether their production has effects on the plant community. If plants do incorporate sulfides into their overall response repertoire, the effect could be substantial and an understanding of the phenomenon could significantly alter future investigations of community and ecosystem relationships.