Abstract: We studied the development of embryo of Bolbitis angustipinna(Hayata) H. Ito by artificial cultivation and paraffin. The first division plane of the zygote is perpendicular to the prothallus, and parallel to the longitudinal axis of the archegonium neck. The plane is parallel to the prothallus and perpendicular to the longitudinal axis of the archegonium neck at the second zygote division. At the third division, the plane is parallel to the longitudinal axis of the prothallus and perpendicular to the archegonium neck. As the embryo reaches to the spherical phase, the upper and lower parts of the outside of embryo produce the apical cell of the first leaf and the apical cell of the first root respectively at the same time. These two apical cells develop into the first leaf primordium and the first root primordium. Subsequently, the first leaf primordium rapidly divides, breaks the cap-like structure and becomes the first young leaf. The first root primordium divides relatively slower than the first leaf primordium, and then breaks the cap-like structure, and forms the first root. We also discussed the phylogeny of embryo.

Key words: Bolbitis angustipinna, embryo, development