Palmer amaranth (AMAPA) is a troublesome weed in the southeastern United States where it is a common and competitive pest in cotton. The recent discovery of a glyphosate-resistant biotype in Georgia is of particular concern as: (1) the majority of the cotton acreage is devoted to the production of glyphosate-resistant cultivars and (2) confirmed resistance to other herbicides (dinitroanilines, acetolactate synthase inhibitors) limits weed control options in infested fields. Because AMAPA is dioecious and an obligate out-crosser, herbicide-resistance genes can be spread to susceptible populations via pollen movement. The development of a predictive long distance dispersal function (LDDF) requires an estimation of the terminal velocity of pollen grains in response to gravity. This paper will present preliminary data regarding pollen settling speeds and will describe pollen flight times and distances for a range of atmospheric mixing heights and wind speeds. The affects of temperature, humidity and herbicide exposure on pollen viability will also be discussed.