Populnin is a monoglucoside of populnetin which is shown to be identical with kæmpferol. By the methylation and the subsequent hydrolysis of the glucoside a trimethyl ether of kæmpferol is obtained. Its colour reactions and properties indicate definitely that the free hydroxyl group is not in the 3− or 5-position. It has been compared with the isomeric 4′-hydroxy compound and found to be different. Thus the degradation product should have the hydroxyl in the 7-position. This is confirmed by ethylation and comparison of the ethyl ether and of its alkali degradation product (ketone) with synthetic samples.