Abstract: Bases on fixed plants observation,this paper studied the flowering phenology of wild and artificial Magnolia sieboldii populations.The results showed that the blooming time lasted about 20 days,from the middle and last ten day of May to the middle and last of June.Full blooming time was from June 1 to 5,and the flower parts changed distinctly in blooming time.Pollens were not mature at beginning flowering,when the pistil had already matured,with pistil stem elongated.After about 20 hours,the stigmas which had already turned black at basal part were wet.After about another 40 hours,pollens turned to mature and anther became splitting.The stigmas at basal and middle parts of the receptacle received more pollens than those at the apical.Pollen lost vigor after 6 days,with 65% of pollination rate.The mean number of per accepted pollen stigma was 3.5,and the rate of fruit set was 13.5% under natural conditions,20.1% in planting,11.3% as taking out the perianth,10.7% if there was no stamen,and 25.0% in condition of pollination by manpower.The pollination efficiency passed by the insects of M.sieboldii was low because of fewer visiting insects and fewer visiting frequency.Bee and a species of Aphididae were the most effective pollinators.Cornus controversa,whose flowering phase was the same as M.sieboldii,had a competition with the passing pollen insects.The insect-visiting rate was affected by several environment factors such as light,temperature,rain and altitude,and the visitation peak was different in different habitats and under different weather conditions.The brighter the sky was,the higher the visitation rate and visiting peak came earlier.

Key words: Organic rice field, Pests, Enemies, Population dynamics