Being able to sense time helps us do everything from waking and sleeping to knowing precisely when to catch a ball that's hurtling towards us. And we owe all these abilities to an interconnected system of timekeepers in our brains. But...

Morning glories unfurl their petals like clockwork in the early morning. A closing white waterlily signals that it's late afternoon. And moon flowers, as their name suggests, only bloom under the night sky. What gives plants this innate...