Marsh Rattlesnake Master

Eryngium aquaticum is a species of flowering plant in the family Apiaceae known by the common name rattlesnakemaster, marsh rattlesnake master, corn-snakeroot, bitter snakeroot, and marsh eryngo. This plant is native to eastern North America.

This biennial or perennial herb grows up to 2 meters (6 ft 7 in) tall. The ribbed, erect stem branches toward the top. There are alternately arranged leaves which are lance-shaped and toothed on the edges. The basal leaves may be up to 90 centimeters (35 in) long by 9 cm (3.5 in) wide. The inflorescence contains white to blue flower heads with spiny, blue-tinged bracts.