This section is from the "The Herb Hunters Guide" book, by A. F. Sievers. Also available from Amazon: Herb Hunters Guide.

Figure 126.Yellowroot (Xanthorhiza simplicissima)
Zanthorhiza apiifolia L'Her.
Shrub yellowroot, southern yellowroot.
Yellowroot grows in woods from southwestern New York to Kentucky and Florida, chiefly in the mountains
This slightly shrubby plant, 1 to 2 feet high, has compound slender-stemmed leaves 5 to 6 inches long clustered at the summit of the short stem. The leaves consist usually of five thin leaflets 1 to 3 inches long, with sharp, irregular teeth. The small, purplish-brown flowers are produced in spring, borne either singly or in clusters from terminal scaly buds. A characteristic of this plant is the bright-yellow color and bitter taste of its bark and long roots.
The roots.
 
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