Abstract: 1. The development of the embryo of roxburgh rose (Rosa roxburghii Tratt. f. normalis Rehd. et Wils.) conforms to the Asterad type with significant variation of forming an oblique wall after the division of the apical cell. A wedge-shaped epiphysis initial is cut off and remained in early stages of proembryo. The mature embryo is typical in dicotyledons and accumunates large amount of protein bodies in its two cotyledons. 2. The endosperm formation is nuclear type. Since the free nuclei become completely separated by the cell wall, the cells in the surface layer of the cellular endosperm may divide periclinally to form a stratified cell zone, as we called secondary endosperm, lining along the boundary of the embryo sac. During the formation of secondary endosperm, the rest endosperm cells degenerate gradually. In mature seed only the secondary endosperm persists and contacts directly with the mature embryo, except at the chalazal end, where it degenerates earlier. 3. The results of this study reveal that degneration of embryo and endoeperm at early stages of embryogeny in some ovules, perhaps caused by the insufficiency of nutrients, may be one of the reasons of seed abortion.

Key words: Rosa roxburghii Tratt. f. normalis Rehd. et Wils, Development of embryo, Endosperm