SAFRANAL (I) and its glycosidic precursor picrocrocin (the bitterprinciple of saffron)1 have been shown by Kuhn, Moewus and Wendt2 to play a remarkable part in controlling the sexual characteristics of the hermaphroditic green alga Chlamydomonas eugametos f. synoica. It was demonstrated that the glycoside acted as a gynotermone for the organism (that is, caused the cells to become female), the minimum