The structures of two novel indole alkaloids, vallesamine and its O‐acetate, isolated from Vallesia dichotoma RUIZ et PAV, have been established as IIIa and IIIb on the basis of extensive NMR. and mass spectral measurements as well as by interconversion with apparicine (I). Copyright © 1964 Verlag GmbH & Co. KGaA, Weinheim