We have previously [1] reported the isolation from the roots of Ungernia spiralis of two alkaloids with mp 148-149°C and 141°C and the respective compositions C17H17NO5 and C17H19NO5. These bases proved to be new and were called ungspiroline (I) and ungspirolidine (II). We now give information concerning their structures. The UV spectrum of (I) has three absorption maxima at 229, 270, 310 nm (log ε 4.44, 3.82, 3.78) characteristic for macronine-type alkaloids. Its IR spectrum shows bands at 3300-3340 (>NH), 1715 (>C=O), 1485, 1510, 1615 (aromatic ring) cm⁻¹. The NMR spectrum (CDCl₃) has singlets at 2.40, 3.10 (aromatic protons at C9 and C12), 3.95 (2H, -O-CH₂O), 6.52 (3H, -OCH₃) ppm and one-proton doublets at 3.55 and 4.57 ppm (J=11Hz, olefinic protons at C2 and C1). The mass spectrum has a molecular ion peak at m/z 315 and other peaks at 301, 286, 272, 261, 243, 231, 171, 56. Hess methylation of (I) gave a substance identical with epimacronine, indicating ungspiroline is possibly de-N-methylepimacronine. The UV spectrum of (II) (λ ethanol 230, 270, 309 nm, log ε 4.30, 3.70, 3.63) is similar to (I). Its IR spectrum is similar to (I) but differs in the fingerprint region. The NMR spectrum has singlets at 2.53, 3.07 (aromatic protons at C9 and C12), 4.02 (2H, -O-CH₂O), 6.68 (3H, -OCH₃) ppm. The mass spectrum has a molecular ion peak at m/z 317 and other peaks at 303, 288, 272, 261, 231, 171, 56. Comparison with (I) and formation of (II) by Adams reduction of (I) show (II) is possibly dihydroungspiroline.