Abstract: The floral development of a critically endangered plant Euryodendron excelsum from Ternstroemioideae (Theaceae) has been observed under scanning electron microscope (SEM) for the first time . The flower of E. excelsum is bisexual and teleianthous . Five sepal primordia are initiated 2􊄯5 spirally and arranged in one whorl when mature , and so are petals. Sepals and petals are initiated in the same order either clockwise or counterclockwise in the same flower . The androecial part is a ring primordium in the beginning . The first five stamen primordia are initiated on this ring primordium at antisepalous positions and then other stamen primordia appear on two sides of each of the first five primordia . Finally a total of 25 stamen primordia are initiated from the ring primordium and arranged in one whorl but could be grouped into 5 fascicles. Three sequentially initiated carpels compose an ovary which has an axile- central placenta with three locules and a truncate
and indehiscent stigma . The floral development of E. excelsum is distinctly different from plants in Theoideae .

Key words: Theaceae