Those rows of wiggly lines are microscopic ridges on the surface of a flower petal. Plant experts have known about them for at least 75 years, but their exact function still remains a mystery.

With petals, the arrows appear more fanned out, which explains how flower petals tend to have more rounded ends than leaves, the researchers said. Sign up for the Live Science daily newsletter now.

Scientists recently discovered a solitary bee that cuts flower petals and forms them into tiny cocoons like papier-mache. These productive little artists make a nest less than an inch long for ...