The reproductive success of Hesperoyucca whipplei , a species native to Southern Californian chaparral, depends on its sole pollinator, Tegeticula maculata , or the yucca moth. The moth pollinates the flowers of H. whipplei and lays its eggs in the developing fruit. In the Los Angeles area, populations of H. whipplei are scattered. Transfer of genetic material between plants is limited by the distance that the moth can or will travel. I mapped populations of H. whipplei in the Los Angeles area using handheld GPS units. In five populations, the locations of 375 reproductive individuals were recorded, and leaf samples for use in genetic analysis were also taken from each individual. These samples will be used in the fall to determine parentage of seeds produced in order to reveal spatial patterns of pollen transfer and their effects of on genetic diversity.