How do Asteraceae flowers ensure seed production if cross-pollination does not occur?

To ensure seed production when cross-pollination does not occur, members of the Asteraceae family utilize two primary mechanisms:

• Self-Pollination: Many Asteraceae employ a system known as plunger, or secondary, pollination. In this process, the style elongates through a tube of anthers, pushing pollen upward on specialized hairs. While this mechanism is designed to facilitate outcrossing by presenting pollen to insects, the stigma will curl down toward the end of its receptive period to collect any remaining pollen from these hairs, thereby ensuring self-pollination if cross-pollination has not taken place.1
• Apomixis: Some species and genera within the family reproduce through apomixis, which is the development of a seed without fertilization. This process allows plants to produce viable seeds even in the absence of sexual reproduction. Apomixis is notably common in certain groups, such as the genus Antennaria, and is often associated with polyploidy or a history of hybridization within the family.21