Continuing a study of the alkaloid composition of various organs of the plant Ungernia vvedenskyi S. Khamidh. (family Amaryllidaceae), we investigated the flowers with peduncles collected in August 1976 in the Chimkent oblast of KazSSR. Chloroform extraction yielded 0.36% of combined alkaloids, which were separated on a silica gel column. A benzene-methanol (99:1) eluate gave a new base (0.024% of dry plant weight) named ungvedine (I), with mp 148-150°C, [α]D +12.5° (c 0.528; chloroform), and composition C19H25NO5. The UV, IR, mass, and NMR spectra suggested I might be O-methyldihydrotazettine. To confirm the structure, tazettine (II) was methylated with methyl iodide/sodium hydride in dimethylformamide, yielding a base identical to I (by TLC, mixed melting point, and mass spectrum). Subsequent eluates gave O-methyltazettine (III), which on hydrogenation (Adams method, Pt catalyst in 10% acetic acid) formed a substance identical to I. Thus, the structure of ungvedine (I) was determined as O-methyldihydrotazettine.