Kinetin (1⋅10−4 M and 1⋅10−3 M) was applied to the plumules of 6-day-old Chenopodium rubrum plants. Effects on growth, anatomical structure and organogenesis in the apical meristem were followed. Floral differentiation as affected by kinetin was also investigated in plants induced to flower by short-day treatment. Kinetin increased mitotic activity in the apical meristems in both induced and non-induced plants. The effect was most pronounced in the peripheral and subcentral zone. An increase in nucleolus size and a higher degree of pyroninophilia in the peripheral zone was also observed, indicating a localized promotion of RNA synthesis. A higher rate of leaf initiation and a stimulation of leaf and stem growth was subse quentiy recorded. The growth of axillary meristems and of bud primordia was promoted only at the lower concentration of kinetin (1⋅10−4 M), in both photoperiodically-induced and non-induced plants. However, the pattern of lateral bud growth differed from that found in normal floral differentiation. In kinetintreated plants, the bud primordia are isolated from the summit of the shoot apex by a succession of rapidly growing leaves. The enhancement of leaf growth leads to correlative inhibition of axillary bud priniordia and results, finally, in a suppression of floral differentiation. The inhibitory effect of kinetin on flowering was compared with that of auxin. Inhibition of flowering occurred in both cases but is achieved in two different ways.