The minor alkaloids (-)-eburnamine (3) and (+)-pycnanthinine (4), an until now unknown dimeric alkaloid C40H46N4O2, have been isolated from the root bark of Pleiocarpa pycnantha (K. Schum.) Stapf. Acid hydrolysis of 4 gave formaldehyde, (+)-pleiocarpamine (1) and (-)-6,7-dehydro-aspidospermidine (7), the N(a)-methyl derivative (6) of 7 also being formed under reductive conditions. These results, together with physical data, particularly an analysis of the 100 Mc NMR-spectrum, have lead to the structure 4 for pycnanthinine, closely related to that of (+)-pycnanthine (2). © 1967 Springer-Verlag.