Carnivorous leaves show their true colours

Leaves are not simply green and flat. They may be scarlet, spotted or scented, move, sweat or even trap prey.

These modifications have evolved to allow plants to survive in special habitats or circumstances.

The leaflets of mimosa fold shut instantly when touched - probably to discourage animals from eating the plant. They open out again about 15 minutes later.

Carnivorous plants grow in poor soils so get their nutrients from another source - insects. The leaf of Venus' flytrap is hinged down the middle. When the triggers in the centre are touched by an insect, the two halves of the leaf snap shut, snaring it.

Because the roots and stems of the mangrove kandelia take up salt from sea water, their leaves contain special salt glands to pump out any excess. This salt crystallises on the leaves, making the tree look as if it's sweating.

Have your ever noticed that the leaves which fall from trees are never green but nearly always brown, red or yellow? This is because the green pigment chlorophyll is absorbed back into the plant stems before the leaves fall, leaving behind the yellow brown substance tannin.