Botanical name: 

Senega, the root of a small North American plant (Polygala senega), enjoyed very early a reputation as one of the new remedies produced by America. The Seneca Indians of New York State employed it as a remedy for the bite of the rattlesnake, which led to its notoriety in the hands of Tennent, a Scotch physician in Virginia, who also administered it for coughs. Under the name senega, or rattlesnake root, it came to the attention of Dr. Mead, of London, and through his efforts and those of others (even Linnaeus [385] writing a dissertation on it) senega root came into great demand. In domestic American medicine it has been continually used as an expectorant, the usual form being that of a syrup.

The History of the Vegetable Drugs of the U.S.P., 1911, was written by John Uri Lloyd.