Abstract: Before May the first, the ovular primordium of Torreya grandis has differentiated. From this early moment the primordium look like the parabolic form and it is surrounded by many pairs of scales, of which a pair of the inner scales are lying at the same level as the primordium of ovule. About May the first of the second year, the differentiation of the various tissues in the ovule has essentially completed. And the fertilization takes place from the end of August to the beginning of September. After overwintering, the proembryo developes into a young embryo in April of the third year, and at the last stage both the seed and the embryo become mature from September to November. In the Taxaceae, the embryogenesis is similar in Amentotaxus,Austrotaxus, Taxus, and Pseudotaxus; their proembryos form cell wall all at the stage of 16-free nuclei and simple polyembryony is common among them. In Torreya, however, the cell wall of proembryo appear at the stage of 4 or 8-free nuclei, and cleavage polyembryony is its feature. On the basis of our observation, the sexual reproductive cycle of Torreya grandis seems to have two important features, one of which is rather long (31 moths from ovular primordium to seed maturity; about 4 months from pollination to fertilization and 7-8 months for development of proembryo). The state of the long sexual cycle in Amentotaxus and Austrotaxus is different from each other; in the former development of young embryo lasts 10-11 months, and in the latter the interval between pollination and fertilization is 13.5 months. The second feature of the sexual cycle in Torreya grandis is over two winters: development of the sporogenous cells in the first, and the proembryo development in the second. From the point of view of phylogenesis, some primitive characters are present in the sexual cycle of Torreya grandis although a specialized feature of the embryogenesis occurs in some degree.

Key words: Torreya grandis, Sexual reproductive cycle, Fertilization, Proembryo