\Xan`tho*rhi"za\, n. [NL., fr. Gr. xanqo`s yellow +
"ri`za 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.