XVI International Botanical Congess

Within the endemic Hawaiian lineage of Schiedea (Caryophyllaceae), evolution of breeding systems has resulted in hermaphroditism, gynodioecy with a wide range of females in populations, subdioecy, and dioecy. Sex allocation patterns as well as the extent of sexual dimorphism in floral characteristics also have changed within the lineage. Sexual dimorphism of flowers is not necessarily greater with a greater proportion of females in populations. Allocation patterns to flowers and fruits differ in females and hermaphrodites, depending on pollination intensity. Knowledge of the past evolutionary history coupled with knowledge of selective pressures resulting from shifts in pollination vect ors contribute to our understanding of patterns of sexual dimorphism within this lineage.