Abstract: This paper gives some details about the development of embryo in Lygodium japonicum (Thunb.)Sw. using the method of serial sections. In this species, the first division of zygote produces two equal hemispheric cells by the first partition wall at the right angles to the axis of the archegonium. The daughter cell near the neck of the archegonium gives rise to the vegetable organs, the other cell away from the neck develops to the feet. The apical cell of the first leaf and of the first root originate almost at the same time after the embryo reaches to the 32-celled phase. The second leaf takes place at the basal part of the first leaf and originates from the shoot apex cells when the first leaf pierces the calyptra. On the basis of the structure of vegetable organs, the first leaf and root are the earliest organs in the development of embryo.

Key words: Lygodium japonicum(Thunb.)Sw., embryo, development