Why Do Houseplants Have Holey Leaves?

Evolutionary biologist Christopher Muir has seen plenty of unusual vegetation while exploring tropical rainforests, from a foot-long flower to a plant that uses ants to protect itself. But it was in a hallway near his office at the University of the Balearic Islands in Spain that he spied something truly memorable: a holey houseplant, Monstera deliciosa, also known as the Swiss cheese plant for the large holes that punctuate its leaves.