Heteromeles arbutifolia, the California holly, is an evergreen shrub native to chaparral habitats of Southern California that fruits from November to January. Fruit species morphology has been shown to be a good indicator of habitat quality among other plants. The variation in fruit morphology was examined for the native plant at two diverse Southern California sites, a wetland and a canyon. California Holly fruits had a significantly greater volume in Ballona Wetlands than at Temescal Canyon (Z=4.367, P<.001), as well as a significantly greater variance in Ballona Wetlands than at Temescal Canyon (F=2.357, P=0.02). The production of fruits with larger and more variable volumes in Ballona Wetlands may be a response to the presence of urban influences and environmental contaminants. As the reproductive structure, fruit morphology may be a good indicator of how habitat stress influences reproductive success.