Abstract: A comparative isoflavonoid analysis of 22 species of Iris, representing almost all the subgenera, and one species of its allied genus Balamcanda, B. chinensis (L.) DC. was carried out by TLC, with iridin, tectoridin, irigenin, tectorigenin, irisfloretin, dichotomin, wogonin, rhamnazin, apocynin, androsin being used as authentic compounds. The results show that the isoflavones are the characteristic constituents of Iris and Belamcanda. According to the distribution pattern of isoflavones, the Iris species here studied can be divided into 2 groups; one contains isoflavonoid aglycons, while the other contains both glycosides and isoflavonoid aglycons. From the point view of chemosystematics, subgen. Limniris contains isoflavonoid aglycons only and might be a natural group; subgen. Crossiris might be also a natural group when Iris speculatrix Hance is excluded; subgen. Pardanthopsis is similar to B. chinensis in the chemical constituent might be a primitive group in Iris and has close relationship with subgen. Crossiris, subgen. Xyridion and subgen. Iris. Based on the evidence from phytochemistry, palynology and cytology, Iris cathayensis Migo and I. mandshurica Pall. are considered intermediate groups between subgen. Limniris and subgen. Iris and I. speculatrix Hance an intermediate group between subgen. Limniris and subgen.Crossiris, while I. confusa Sealy and I. wattii Baker might be conspecific.

Key words: Iris, Belamcanda, Isoflavones, Systematics