☆ any of a genus (Coptis) of North American plants of the buttercup family, esp. a small perennial (C. groenlandica) with white flowers and yellow rhizomes, used in folk medicine
See goldthread in American Heritage Dictionary 4
(gōldˈthrĕdˌ)
noun
Any of several plants of the genus Coptis, having white flowers, slender yellow roots, ternately divided evergreen leaves, and clusters of follicles.