Abstract. A development of floral morphogenesis was presented from the vegetative to the late reproductive stages by photoperiod for chrysanthemum (Dendranthema grandiflorum) cultivars ‘Envy’ and ‘Lady Time’. To quantify the flowering process, times to specific stage assigned numerical values. When the developments of floral stages were plotted against time after the commencement of short-day induction, they produced nearly straight lines on a graph and it was possible to compare the flowering progress among various photoperiod treatments. Optimum photoperiod for progress to anthesis was 10 h in both cultivars. Plants grown under 10 h photoperiod reached anthesis up to seven days earlier than those grown at 8 or 12 h photoperiods. In continuous 14 and 16 h photoperiods, both cultivars eventually initiated flower buds (crown buds), which failed to reach anthesis. Final leaf number at anthesis in ‘Envy’ was less affected by photoperiod. While overall plant growth, measured as dry weight, stem length and leaf area, increased as photoperiods were extended from 10 to 16 h.