Cohen, M., Northern R and D, P.O. Box 831, Kiryat Shmona 11016, Israel
Zemach, H., Department of Ornamental Horticulture ARO, Volcani Center, Bet-Dagan 50250, Israel
Ben-Jaacov, J., Department of Ornamental Horticulture ARO, Volcani Center, Bet-Dagan 50250, Israel
Kamenetsky, R., Department of Ornamental Horticulture ARO, Volcani Center, Bet-Dagan 50250, Israel

The production of ornamental branches of Leucadendron 'Safari Sunset' in the northern regions of Israel resulted in the export of 23 million stems to the European and American market in 2006. The economic value of this crop is provided by the deep red color of the involucral leaves and its typical "head" form. In this research, reproductive development of 'Safari Sunset' was studied during the annual crop life cycle. The transition from the vegetative to the reproductive stage occurs in the autumn, and individual flowers develop in the axils of the inflorescence bracts. In the early stages of differentiation, flowers of 'Safari Sunset' contain both female and male organs. Exposure to a short photoperiod resulted in earlier flower initiation and differentiation, but shorter stems and smaller "heads". Total Soluble Solids (TSS) of the vegetative organs (lower, upper and involucral leaves) remained stable during vegetative growth, floral initiation and growth of the inflorescence. However, TSS of the inflorescence increased dramatically during its differentiation and growth, and decreased to the initial level when "head" maturation was completed. Pruning height (i.e. stump or bearer length) significantly affected the rate of the "head" maturation but did not change the course of the florogenesis.