Some years ago, one of us reported the isolation of a minor constituent of the seed alkaloid of Heliotropium europaeum and assigned to it the formula C12H17O4N or C12H19O4N (1). The compound was isolated from a countercurrent distribution fraction consisting largely of heliotrine (I) and has not been detected in numerous other separations of the alkaloids of this species. Data accumulated since has shown that the compound is more complex than originally thought and its essential character was recognised during recent studies on the dihydropyrrolizine analogues of the pyrrolizidine alkaloids (2). The structure (II), regarded as the product of alkylation of a molecule of heliotrine by dehydroheliotrine (III), is now assigned to this substance. It appears to occur naturally in H. europaeum and thus provides the first evidence that the dihydropyrrolizine analogues are formed in plant species along with the known alkaloids.