Andromonoecism, protandry, and sexual selection in Umbelliferae

Abstract

Summary Most Umbelliferae are protandrous and andromonoecious with hermaphrodite flowers concentrated in earlier opening umbellets and umbel orders. When weakly developed: protogyny is more effective than protandry in promoting outcrossing, yet is uncommon. It ts suggested that sexual selection, rather than selection for outcrossing, explains the Widespread occurrence of protandry. When protandry is strongly developed, male and female phases may be completely separated in time within a plant so that outcrossing is assured.