The expression and probable genetic control of andromonoecy has been reported in coriander. Highly significant varietal differences were observed in respect of all the characters under study. Male flowers occur intermixed throughout the coriander inflorescence. Early opening flowers in an umbellet are generally hermaphrodite. Decondensing the umbellet, as it were, by using the order of anthesis, it appeared that there is a sharp transition from an earlier hermaphrodite phase to a succeeding male phase in the coriander umbellet. Use of plant growth regulators and gametocide altered the ratio of male to perfect flowers, lowering it. The differentiation of the two types of flowers has been considered as an epigenetic phenomenon and the genetic control of this phenomenon has been discussed.