Treatment with chlorflurecol, a morphactin, resulted in shortening of the main shoot, delayed release of inhibition of the lateral buds, retardation of internodal length, malformation of leaves, and late flowering. The size of the capitular receptacle was reduced and the orderly initiation of bracts and florets was disrupted. Chlorflurecol treatment substantially curtailed the mitotic activity of the tunica, corpus, pith rib meristem and intercalary regions. The barren capitula, however, when excised and cultured on a medium containing IAA + GA3 + kinetin resumed mitotic activity in the tunica and outer corpus layers and produced flower or vegetative buds. Chlorflurenol treatment delayed early winter shoot growth but stimulated shoot growth later in the season, giving compact healthy plants with many flowers. Chlorflurenol can thus be used to obtain flowers in the off season.