Our materia medica is expanding to include medicinal plants of China. But how do we know if we have the correct species of xuan shen (Scrophularia buergeriana) or dan shen (Salvia miltiorrhiza)? We’re very lucky to have access to the Flora of China online. What other sources of information exist for identifying the correct herb material. What about adulteration and substitution? What East Asian herbs are now extinct in the wild and only cultivated and how can we learn to cultivate them?