The Green Planet

More kinds of plants are crammed together in the tropical rainforests than anywhere else on Earth. The result is astonishing beauty and intense competition - a plant battleground. From fast-growing trees to flowers that mimic dead animals, this is a journey into a magical world that operates on a different timescale to our own.

Water plants create some of the most beautiful, bizarre and important habitats on earth. Some are armed with vicious weapons to fight titanic battles for space. Others form perfect spheres and escape from animal enemies by rolling. Where nutrients are washed away, plants turn into hunters of animals, laying traps and even counting to ensure their success.

Between the tropics and the frozen poles lies a region dominated by relentless change in the form of the four seasons: spring, summer, autumn and winter. Each one presents plants with huge challenges. To survive here plants must use strategy, deception and remarkable feats of engineering. Most importantly, they must get their timing right.

Deserts are hostile; temperatures soar and water is rare. Yet plants find extraordinary ways to survive. They may grow imperceptibly slowly, travel the landscape looking for water, or wait decades in suspended animation. Plants have invaded the most dangerous deserts on earth, overcoming salt, fire and toxic bird droppings to bring life and colour to these harsh landscapes.

We rely on plants for almost everything, including the air we breathe and the food we eat. Two in five wild plants are threatened with extinction, but people are finding new ways to help them, from projects in Africa to reseed the landscape to the rebuilding of a tropical forest in Brazil, tree by tree.