Dovetree (Davidia involucrata) is an endemic, endangered species to China in the monotypic family Davidiaceae. The name of this plant comes from its inflorescences each with a pair of large but unequal white bracts which are flowering in spring like many doves standing in the tree on mountains. It is one of most beautiful plants with systematics importance, but the reproductive biology of this andromonoecious species has been largely ignored. During 2000 to 2001, we conducted field pollination observations in two populations in Hubei Province, China. We estimated the sex ratios of male to cosexual inflorescences of sampled plants and recorded visiting frequencies of different insect vectors. During about one week anthesis, insect visits were rare in both populations. The major visitors are beetles, occasionally flies and bees. By experimental manipulations, we assessed the function of two white bracts and two types of stamens in an inflorescence, a few stamens of short filaments in hermaphrodite flower and more than one thousand stamens of long filaments in male flowers. One fruit may potential contain 6-9 seeds, but most fruits only germinated one or two seedlings. Pollen limitation and fruit predation by insect parasite are likely to be two main factors to limit the reproductive success of this plant.

Key words: andromonoecy, Davidia involucrata, Davidiaceae, endangered plant, pollination, reproductive success