These traps are all classified as "active" or "passive". "Triphyophyllum" is a liana (a climber in tropical forests). It has three types of leaves. When needed, it puts out long leaves. These are passive 'flypapers' which hide mucus. The leaves of the plant do not grow or move as a response to moving prey. The Sundew "Drosera", on the other hand, is an active flypaper. All species of Sundew are able to move their sticky tentacles in response to a contact. The tentacles are very sensitive and will bend toward the center of the leaf in order to bring the insect into contact with as many stalked glands as possible. According to Darwin, the touch of legs of a small gnat with a single tentacle is enough to cause this response. This helps the catch and digestion of prey.