Abstract: Hernandia nymphaeifolia is an endangered semi-mangrove species. Floral characteristic is of great significance for the conservation of endangered species. There are two flowering types of H. nymphaeifolia: one type with exclusively female flowers open in the morning and male flowers open in the afternoon named as protogyny, and the other type with the reverse behavior named as protandry. The stigma receptivity and pollen viability had high activities in both female and male functional stages. As for seed-setting rate, outcross pollination was the highest type (43.40%), followed by natural pollination (20.20%), geitonogamy (1.04%), and no apomixis, indicating that the breeding system of H. nymphaeifolia was self-incompatibility. In conclusion, the female and male functions of H. nymphaeifolia are normal, but the small population size leads to self-incompatibility, which is the main reason for the low seed-setting rate of H. nymphaeifolia.

Key words: endangered semi-mangrove plant, Hernandia nymphaeifolia, flowering biology, heterodichogamy, self-incompatibility