pyrethrum (derived from Old World members of the genus Chrysanthemum) is a natural insecticide with minimal environmental impact. Wormwood, derived from a genus that includes the sagebrush, is used as a source of flavoring for absinthe, a bitter classical liquor of European origin. References Further reading W. S. Judd, C. S. Campbell, E. A. Kellogg, P. F. Stevens, M. J. Donoghue (2002). Plant Systematics: A Phylogenetic Approach, 2nd edition. pp. 476–486 (Asterales). Sinauer Associates, Sunderland, Massachusetts. . External links Angiosperm orders