Detailed chemical examination of the roots ofD. ferruginea has now been carried out. Of the two varieties, the rotenone-free one is further characterised by not giving any crystalline component. The rotenonebearing variety yields besides rotenone (4·3%), only a small amount of dehydro-rotenone. The chemical chaaracteristics of rotenone-bearingD. ferruginea andD. elliptica are compared. It seems to be possible to use chemical composition to distinguish one from the other.