Two flavons, which are a new flavon (the Authors are going to call it "CLEMATISIN") and a yellow crystalline flavon, are isolated from leaves of Clematis brachura Maxim. Clamatisin : A colorless needle crystal which has a Slightly sweet taste, mp 225 .deg.C (decomp). It is positive (Cherry red) for the Mg-HCl(Hg) reaction and is positive (purple) for the $FeCL_{3}$ reagent. It is soluble easily in methanol, ether, acetone, prydine, ethylacetate, hot water and alkali-solutions. It is soluble slightly in cold water and is insoluble in chloroform, benzene and toluence. According to the results of elementry analysis and molecular weight determination the formula of clematisin agrees with $C_{18}H_{18}O_{7}$ when dried at $80^{circ}C$, crystalline clematisin (from water) contains one molecule of crystalline water. The following derivatives are prepared ; Clematisin-oxim; a colorless needle crystal, mp 215-216 .deg.C, Clematisin methylate; prepared by diazomethan. mp 191-$192^{circ}C$ a colorless needle crystal. Acethylmethylate; a colorless powder, It is not sharp in melting point and melts at approximately $215^{circ}C$, Yellow Crystalline Flavon; mp 285-$286^{circ}C$ (dexo-mp.), yellow needle crystal. It has a slightly sweet teste and shows positive reaction Acetate; a colorless needle crystal, mp $168^{circ}C$.