THE FLORAL BIOLOGY AND ITS EVOLUTIONARY SIGNIFICANCE OF SINOPODOPHYLLUM HEXANDRUM(ROYLE) YING(BERBERIDACEAE)

The floral biology of nine populations of Sinopodophyllum hexandrum (Royle)Ying(Berberaceae) (Ximalaya mayapple ) in Zhongdian area,Yunnan Province,has beenstudied.The results are presented as follows: (l ) It has been observed that Ximalayamayapple has a very special pollination mechanism which adapts to autogamy.When theflower is under blossom or just in blossom,the gynoecium is upright.When the flower isin full blossom,however,the gynoecium takes place a turning and makes the whole gynoecium close to a certain anther.The stigma thus contacts with the anther and pollination occurs.After pollination,the gynoecium recovers to upright.The whole pollinationprocess lasts about 4-6 hours.(2)The reproductive rhythm of the plant is quite fast,from the meiosis of spore--mother cell to the termination of double fertilization,it takesonly about 4-6 days.Fruit--bearing rate is almost 100%,seedset ratio is 97.32 %.(3)Ximalaya mayapple has a strong differentiation within species and shows its diversity inboth morphology and ecological adaptation.The plant is,therefore,believed to be with alarge present fitness.