From the leaves of Liriodendron tulipifera have been isolated d-caaverine and a new aporphine alkaloid—lirinidine—with the composition C18H19O2N, [α](Formula presented.) +78° (c 0.19; chloroform). On the basis of features of its UV, IR, NMR, and mass spectra and chemical transformations, the structure of 5-hydroxy-6-methoxyaporphine has been established for lirinidine. © 1975, Plenum Publishing Corporation. All rights reserved.