Abstract: Phenotypic plasticity is the environmental modification of genotypic expression  and an important means by which individual plants respond to environmental heterogeneity.  The study of phenotypic plasticity in the genus Adenophora, which is very complicated taxo-  nomically because of great morphological variation, proves to be helpful in both investigating  the phenotypic variation so as to evaluate potential taxonomic value of their characters and  providing important sources of information on the variation, adaptation and evolution of the  genus. Twenty-three populations representing all the six species in Adenophora potaninii  complex were transplanted into the garden. Of them six populations were selected for study-  ing their performance in the field and in the garden, in addition to cultivation experiment  under different treatments. The results show that there exists considerable developmental  plasticity in some leaf, floral and capsule characters. In particular, the leaf shape and length  of calyx lobe display significant developmental variation with the maximum being three times  as great as the minimum, which is noteworthy because they were previously considered as  diagnostic. The characters of root, caudex, stem and inflorescence are found to be very  plastic, especially the root diameter, the number of stems, stem height and inflorescence  length with great environmental plasticity. In addition, the populations from different habi-  tats show distinct amounts of plasticity. On the contrary, the characters of leaf, floral, cap-  sule and seed are less influenced by environments. It seems that the considerable variation in the characters of leaf is attributed mainly to genetic differences. Finally, the phenotypic plasticity of morphological characters of A. potaninii complex and its taxonomic significanceis discussed.