Eupatorium pilosum, rough boneset, is a rare North American species of plant in sunflower family. It is native to the eastern and south-central United States, found in every coastal state from Massachusetts to Texas, and as far inland as Kentucky. Eupatorium pilosum is a perennial herb sometimes over 100 cm (40 inches) tall, spreading by means of underground rhizomes. The plant produces large displays of large numbers of tiny flower heads, each with 5 white disc florets but no ray florets