A closed white water lily indicates that it is late afternoon, and the moon flower,

A closing white water lily signals that it's late afternoon, and moon flowers, as the name suggests, only bloom under the night sky.
But what gives plants this innate sense of time? It's not just plants, in fact. Many organisms on Earth have a seemingly inherent awareness of where they are in the day's cycle. That's because of circadian rhythms, the internal timekeepers that tick away inside many living things. These biological clocks allow organisms
to keep track of time and pick up on environmental cues that help them adapt.