Abstract: Fifty-two plant samples from six species of Rehmannia and two species of
Triaenophora of Scrophulariaceae were investigated using ultra-thin slab IEF-PAGE in this
study. The results showed that forty-five alleles of eighteen loci were present in seven
enzymatic systems, and seventeen of eighteen loci were polymorphic. The data further
determined by Biosys-1 indicated that individuals of the same species exhibited relatively
strong genetic homogeneity, while individuals of different species showed statistically
significant genetic heterogeneity. We also found that among the eight species, except R. elata
and R. piasezkii, six showed relatively obvious statistically significant genetic differentiation.
Moreover, the eight species could be placed into two groups according to cluster analysis; one
group consists of T. shennongjiaensis and T. rupestris, and the other consists of R. glutinosa,
R. solanifolia, R. chingii, R. henryi, R. elata, and R. piasezkii. The results also showed that in
Rehmannia, R. elata and R. piasezkii were most genetically related to each other, while R.
glutinosa and R. piasezkii were least genetically related. Allozyme study suggested that R.
elata and R. piasezkii should not be regarded as two distinct species. Rehmannia and
Triaenophora shared highly genetic identity with many similar characteristics in their
morphology and life history, indicating their divergence time might not be very long.

Key words: systematics, allozyme, Rehmannia, Triaenophora.