During this field investigation, we found that present distributions of P. japonicus and its varieties were much lower than old records and previous studies during 2004–2006 (Chen and Lin, 2006, Yan et al., 2006, Wu et al., 2007, Tang et al., 2007, Lin et al., 2007), suggesting that these species was at risk of becoming critically endangered. Wild plants of P. japonicus were only known to grow in the wild in 7 natural reserved areas of China: Qizimei Mountain of Hubei, Leigong Mountain of