Commelina benghalensis is a federally noxious weed native to tropical Asia that is invading the southeastern United States. Little is known about the physiological characteristics of C. benghalensis that might define its potential geographical range. Much of the Southeast has highly weathered, acid soils with high levels of aluminum. The ability of C. benghalensis to extensively invade acid soil areas will be related to its Al tolerance. In this study, we examine Al tolerance and the mechanism of Al toxicity in C. benghalensis. Initial hydroponics experiments show that C. benghalensis has a level of Al tolerance that may exceed many agronomic crop and weed species. Tissue Al measurements indicate that tolerance is likely related with Al exclusion from the root, as appears to be the case with many species. Lumogallion staining and confocal microscopy using longitudinal sections of root tips are being used to determine the extent that intercellular Al compartmentation away from root meristematic centers is involved. Additional experiments are targeting Al effects at a higher level of organization. One of the main advantages of C. benghalensis, ecologically, is its ability to produce large numbers of underground seeds. Evidence suggests that rhizosphere acidity stressors can adversely affect above- and below-ground reproductive processes.