Charles Darwin loved carnivorous plants and obtained specimens from Kew Director Joseph Hooker.
Although the plants originated from Australia, Asia and America, they all looked very similar. Botanists at the time thought this was because they were related, but DNA studies have since revealed this is not true. They have simply evolved to catch their food in the same way. Of the 600 or so species of carnivorous plants, 7 or 8 are native to Britain.
Carnivorous plants generally live on poor soils such as acidic peat bogs. Because they cannot obtain sufficient nutrients from the substrate, they trap animals such as midges and flies. Different species have adapted in different ways to enable them to do this.
The venus fly trap (Dionaea), for example, has toothed leaves that snap shut and trap its unsuspecting prey. Other carnivorous plants (such as Sarracenia, Cephalotus, Darlingtonia and Nepenthes) have pitchers with smooth, waxy interior walls.
Insects are attracted to the colours and sweet secretions inside the pitcher but once inside they fall to the bottom, drown and are then digested. Plants such as the sundews (Drosera) and butterworts (Pinguicula) secrete sticky mucus to which insects readily stick.
There is evidence that large tropical species of carnivorous plants are able to trap and digest frogs, birds and small mammals.
Kew’s specimens range from the flamboyant Saracenia leucophylla, which has tall, white-topped pitchers streaked with red or green veins, to the low-growing Australian sundew Drosera adelae, which has glistening reddish green leaves.
As well as the dedicated zone for carnivorous plants there are also some tropical species located in the main Wet Tropics section of the glasshouse.