Japanese Barberry (Berberis thunbergii) is a widespread red-fruiting shrub armed with thin, sharp spines. Berries hang in small clusters and often persist on branches after leaf drop. In autumn, the small, entire leaves change from green to soft shades of red, orange, and yellow.
The roots of Japanese Barberry contain berberine -- a bitter, yellow alkaloid also found in Goldenseal (Hydrastis canadensis), Three-leaved Goldthread (Coptis trifolia) and Common Barberry (B. vulgaris). Extracts containing berberine have been shown to be active against a variety of fungal, viral, and bacterial infections. For more on the medicinal uses of this shrub's roots, check out Arthur Haines' post on Permies.com where he shares an excerpt from his forthcoming foraging book. (Click here for the slideshow.)