Abstract: Gynomonoecy is the mode of sex expression in which female and bisexual flowers occur on the same plant. To date, previous research has primarily focused on its occurrence in Asteraceae. There are two types of hermaphrodite flowers in Silene uniflora Roth., namely fertile and male sterile. As both hermaphrodite and functional female flowers occur, the sex system of S. uniflora is functional gynomonoecy. Fertile hermaphrodite flowers exhibit protandry and dichogamy. Their breeding system includes outcrossing and partial self-pollination. The seed setting rate through autogamy was 31.71%. Some flowers showed malformed stamens and pollen, resulting in reduced pollen output. More functional female flowers were found in the early or later flowering period. Functional gynomonoecious S. uniflora might be advan-tageous to reduce autogamy and interfere with male and female function to improve allogamy. This phylogenetic characteristic is beneficial to the mobility and flexibility of resource allocation.