Abstract: The pattern of development of the floral parts of litchi (Litchi chinensis Sonn.) flower was followed using scanning electron microscopy. Before making scanning electron microscopic observations, specimens were tannin-osmium impregnated and critical point dried. In the bisexual flower, floral organogenesis starts with the formation of protrusions near the floral apex. The two to three protrusions present at the apical region of the floral apex later expand and fuse to form the ovary. At the upper middle region of the ovary another protrusion develops which later becomes the style and the stigma. When the flower matures the tip of the style not only splits but also becomes twisted. On the upper side of the stigma there are numerous papillate cells. These cells are covered with mucilage when fully mature. The development of the filament and anther begins a little bit earlier than the gynoecium. The first sign of androecium development begins when protrusions start to develop around the floral apex. Each litchi flower possesses 6 to 10 anthers. In addition to forming bisexual flowers, litchi also produces a large number of male and female unisexal flowers. But under the scanning electron microscope it is very difficult to distinguish accurately between male and female flowers, because both flowers invariably give rise to some poorly developed organs of the opposite sex. Thus it seems that all flowers in litchi are potentially bisexual and only at the final stage of development (i.e. about 50 days after floral initiation) sex organs fail to develop properly in some flowers.

Key words: Development of the floral parts of litchi, Bisexual and unisexual flowers, Male and female flowers