“Knowing that cyanobacteria have the capacity to see opens the possibility that perhaps the plant kingdom, which evolved from cyanobacteria, never actually discarded it. In the world of light and shadow, where all potential friends and enemies use visual cues to hunt and feed and hide, there's evolutionary reason to believe that once an organism has an eyespot, it would hang onto it. After all, human and all other modern eyes likely evolved from ancient eyespots much like the cyanobacteria's.

Of course, evolution does not always tell such a linear story. Plenty of features across all kingdoms of life have emerged and been dropped over many millions of years, only to pop up again, evolving back into being. But although scientists have not yet located ocelli in plant leaves, that doesn't mean they aren't there. As Baluška and Mancuso argue, no one has yet properly looked.”