Xanthorhiza

Xan′tho‐rhi″za (?), n. [NL., fr. Gr. ξανθόσ yellow + ρἵζα root.] (Bot.) A genus of shrubby ranunculaceous plants of North America, including only the species Xanthorhiza apiifolia, which has roots of a deep yellow color; yellowroot. The bark is intensely bitter, and is sometimes used as a tonic.