Abstract: The paraffin cut method was used to observe the developing process of the flower bud differentiation of Osmanthus f ragrans‘Houban Jingui’. The results showed that the flower bud differentiation process lasted for about 4 months from bract primordia differentiation in mid April to carpel primordia formation in late August . The process could be divided into 7 phases : bract differentiation phase , inflorescence primordium differentiation phase, single flower primordia differentiation phase, sepal differentiation phase of top flower , petal differentiation phase, stamen differentiation phase and pistil differentiation phase. The phase of bract differentiation and stamen differentiation were relatively long, The top flower of the nflorescence differentiated earlier and slower than the lateral flowers , and all the top and lateral flowers finished differentiation almost at the same time.

Key words: Osmanthus f ragrans, Flower bud, Morphological differentiation