Eupatorium altissimum
Eupatorium altissimum, the tall thoroughwort, is a perennial plant whose native range includes much of the eastern and central United States and Canada tall. Leaves and stems are covered with whitish hairs. The plant produces a large number of small white flower heads in a large flat-topped array at the top of the plant. Each head generally has 5 disc florets but no ray florets.
Eupatorium altissimum is part of Eupatorium even when that genus is defined narrowly to include about 40 species of mostly white-flowered plants of North America, Asia, and Europe.
