[Textual studies on shangzhou zhiqiao fructus Aurantii]

The original plant of Shangzhou Zhiqiao, the best among the species of Zhiqino, is confirmed as Citrus aurantium rather than Poncirus trifolia in this paper based on the description and drawings of Zhiqiao in (Bencao Gangmu) by Li Shizhen in the 16th rentury, samples from Shangzhou(Shanxi Province), and the cold-warm period of historical climate in the local area, which is believed to be related to the distribution of C. aurantium in Shangzhou. However, P.trifolia has often been confused with C. aurantium by some herbalists.