Comment by cubefox

The second article goes into more detail:

> To minimize the risk of self-pollination, which can result in inbreeding depression and recessive mutations, the flowers open in the morning and the stigmas are receptive to pollen that is brought to them by foraging beetles throughout the day. When evening comes, the innermost tepals close around the carpel and trap the pollinating beetle. While the tepals are closed, the beetle deposits pollen all over the receptive stigmas. The stigmas then close and the anthers become active, covering the same beetle in fresh pollen so that when the sepals open in the morning, it will fly out and find another flower to pollinate. This precise delay in flower function helps to ensure cross pollination.