Asclepias tuberosa 

The Butterfly Weed or Pleurisy Root is a native plant to North America. Omaha Indians ingested the raw root for its expectorant properties to treat bronchitis. The root also contains the cardiac glycosides found in the leaves of the digitalis species of plants used to treat chronic congestive heart failure and certain abnormalities of the heart rhythum, and an estrogen-like substance resembling the human female hormone estrogen.