The Green Planet Part 4: Desert Worlds

The Green Planet Part 4: Desert Worlds
Plants that have developed to thrive in the desert, including cacti that grow in the shade of other trees and collect water in pleated trunks that expand and contract – but can also find themselves a host to other plants, like desert mistletoe. The programme also reveals how tobacco plants being eaten by caterpillars are able to summon the creatures’ natural predators, and how tumbleweeds roll across the landscape, only unfurling and growing when they encounter rain.