Reproductive success in Daphne gnidium (Thymelaeaceae)

Daphne gnidium L. is a circum-Mediterranean evergreen shrub. The production of flowers and fruits of single individuals within a population were recorded. Despite very high efforts along the flowering season, all plants seemed to show a different allocation of resources during the reproductive process. All plants bore flowers with a complete male function while the female often failed to produce well formed fruits. According to anatomical analyses of reproductive material fallen down to the ground, pre- and a post-zygotic degenerations were observed. These events had no significant correlation with environmental parameters and plant dimension. The complex of data suggests an evolutionary pathway of D. gnidium toward dioecy. Multiple patterns of gender variation are common to other members of the Thymelaeaceae (i.e. Thymelaea hirsuta, Daphne sericea and D. laureola), and always caused very low fruit production like the studied species.