XVI International Botanical Congess
Lythrum salicaria is a wetland invader capable ofcreating monocultures with showy floral displays. Therefore, competition for pollination may occur even at a distance. In three experiments we measured L. alatum seed set along transects perpendicular to L. salicaria populations. The fourth experiment measured L. alatum seed set in sympatric populations and a L. alatum population 0.2 km from the intermixed populations. In the first three experiments there was a small increase in seed set with distance from L. salicaria. In the fourth seed set was reduced by 46% at the intermixed site. Standing crop nectar was not significantly different at any site. Lythrum salicaria reduces seed set, even at distance and may have greater impact on the native flora than previously anticipated