Developmental features from flewer initiation to seed fermation of Cunningha mia lanceolata (Lamb.) Hook. were studied under the optical microscope. Materials used in this study were collected from trees of twenty-year-old in Nanjing during 1976-77. The observations are summarized as follows:1. Cunningharnia lanceolata (Lamb.) Hook. takes about fourteen months, including winter, to complete the development from flower initiation to seed formation. In Nanjing, the flower bud initiation usually begins in early August, pollination in late March or early April of the next year, fertilization in the middle of June, embryo development in July, August and September, and the seed maturity in October.2. The microspores are great in quantity, high in quality, and ripe simultaneously. Therefore, with the artificial supplementary pollination in the flowering period, the quality of the seeds can be greatly improved.3. Cleavage polyembryony and simple polyembryony may occur in the early development of embryogeny.