The proposed research will emphasize the use of patterns of flavonoids, alkaloids, betalains, sesquiterpene lactones and volatile oils as genetic markers in systematic botany. The role of specific members of these classes of natural products play in plant-animal and plant-microorganism co-evolution will be investigated. The structural features of plant products including sesquiterpene lactones, quinones and phenolics which cause allergenic contact dermatitis will be determined utilizing well-defined guinea pig bioassays. Several important pheromones in mice urine will be isolated and structurally investigated when the bioassay can be developed to a point of reliability. Proteins, including plastocyanins in chloroplasts and unusual crystalline proteins in sieve-element plastids, will be isolated, characterized, and sequenced in connection with our efforts to establish the phylogeny of major taxonomic groups in the plant kingdom. BIBLIOGRAPHIC REFERENCES: McMillan, C., T.J. Mabry and P.I. Chavez. 1976. Experimental hybridization of Xanthium strumarium (Compositae) from Asia and America. II. Sesquiterpene lactones of F1 hybrids. Am. J. Bot. 63:317-323. Burnet, W.C., Jr., S.B. Jones, Jr., and T.J. Mabry. 1977. Influence of sesquiterpene lactones of Vernonia (Compositae) on oviposition preferences of Lepidoptera. Amer. Midlands Naturalist. In press.