Abstract: We studied the teproductive biology of Heotacodium miconioides,a national protected plant species in China.The reults showed that there were no pedicels in the flowers of Heptacodium miconioides and teminal panicle was clmposed of several constrictive capitate cyimes.lt usually flowered with the basal and middkw whorls,and some flowered with only the basal whorl.Self-Pollination was high in reproduction.There were over 60 pollens loading on the stigma 4 hours after flowering, and pollens amounted to 142 at modt 8 hours after flowering.At least 1/3 pollens germinated and a few of them could reach ovary in which only 1 ocule ciuld decelop.The average seed set of developed ovule was 40.6^and the seeding of middle whorl woulb influence that of basal who,its decrease rate was 34 8% and the seeding of whorl would influence that of middle whorl.All the results suggested that the seed set in Heptacodium micomioides was mainly caused by resource limitation.

Key words: Heptavodium miconioides