Abstract:The floral morphology and flowering characteristics in Camptotheca acuminata Decne were investigated. Breeding system was characterized by outcrossing index (OCI), pollen-ovule ratio (P/O), and the outcome of bag test and artificial pollination experiment. The results showed that the inflorescences of C. acuminata were cymes, each of which was composed of 4~6 capitula. Within a cyme, the 3~4 distal capitula were composed of hermaphroditic florets, while the 1~2 proximal capitula were composed of male florets. There were one pistil and ten stamens in each hermaphroditic floret. Each pistil possessed an inferior ovary containing an anatropous ovule. The male florets had normal stamens, but had no pistil. The pollen vigor in a capitulum reached its peak in the 2nd day after the pollen dispersal. The stigmatic receptivity reached its peak in 3rd and 4th days in the hermaphroditic florets. Stigma lost its receptivity completely on 6th day after it reflexed outward. C. acuminata was hemisynchronously dichogamous, and all florets of a capitulum bloomed synchronously. The male phase came first, in which the stamen matured. Then came the female phase, in which the pistil matured. The female phase of capitula in one order overlapped with the male phase of those in the next order in the same cyme. C. acuminata were outcrossing, partly self-compatible, and insect-assisted during the pollination.