About Eupatorium rotundifolium L.
Eupatorium rotundifolium L. has stems that grow up to 100 cm (40 inches) tall, and these stems grow from short rhizomes. Its inflorescences are made up of many small white flower heads; each flower head has 5 disc florets and no ray florets. Individual plants of this species can vary widely in form as a result of hybridization. This species is distributed from Massachusetts, New York, Indiana, and Oklahoma southward to southern Florida and Texas. It grows in habitats ranging from moist to dry woodlands, pine savannas, and seepage bogs, and also grows along roadsides. Eupatorium rotundifolium contains guaianolide-type sesquiterpene lactones, including euparotin acetate and eupachlorin acetate. When these two compounds are isolated from the plant, they inhibit tumor growth in vitro. Historically, this plant was used medicinally to treat intermittent fevers.
