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General Information

What are Carnivorous Plants?

Carnivorous plants are the name given to a wide ranging group of plants which only share a single common factor, that is that they all have a method of trapping and digesting living creatures in order to provide a means of nourishment.

How these plants do this varies widely from species to species. Most people think that all Carnivorous plants have traps which shut suddenly on unwary insects. However, the case is that most Carnivorous plants have 'passive' methods of catching their prey, most never move and simply wait for their prey to make a mistake.

Stories of Carnivorous plants being man-eating fiends have also been greatly exaggerated. The majority of Carnivorous plants never grow above a few feet. Even the giant tropical Nepenthes restrict their intake to insects, albeit slightly larger insects.

The cultivation of these plants has often worried newcomers, fearing that the upkeep of these amazing plants is difficult and that the plant rarely outlives a year. This is not the case, if you follow a few simple rules, you should be rewarded with interesting plants which make an interesting point of conversation for many years to come.

Plants can be grown in and out of doors, depending on the type of course, and there are many native British Carnivorous plants. Although most of the plants for sale in the UK come from the USA, there are also species of Carnivorous plants found in Canada, Russia, South America, Asia and Europe.

Types of trap


Traps can be divided initially into active and passive types. Active traps use movement in the process of trapping and digesting their prey, Dionaea (Venus fly trap) being the best known example. The mechanism is reminiscent of an old-fashioned game trap, with two sections hinged open and sprung, waiting to be triggered by the unsuspecting victim. Pinguicula use no movement but catches food with their fly-paper type leaves, but because they roll their leaf margins immediately after trapping to assist digestion they are also classified as active. Similarly, Drosera bend dew-dropped tentacles covering the leaf surface towards the prey, which is stuck to the adhesive droplets, and sometimes bend the entire leaf to surround their food. While they are not as fast as most other active traps, a very few species can bend their leaves in half in less than 60 seconds.
Passive traps such as Sarracenia utilize no movement either in trapping or during digestion. They simply expect the prey to move towards the plant and become ensnared, by falling into a pit or being stuck with a gluey substance.
Traps can also be distinguished by their form. The largest group, known as pitfalls, include all the pitchers. These consist of a tube into which a creature will eventually tumble and are often enhanced with nectaries or colouring to attract the prey, as well as hairs or waxy cells to assist trapping. Sarracenia is a good example of a pitcher which may employ the full range of available inducements. Fly-paper traps, like those of Drosera, use sticky mucus to glue the prey to the leaf blade. The steel-trap of Dionaea snaps shut on any creature unfortunate enough to trigger the sensitive hairs on the trap surface. Mousetraps, such as those of Utricularia, work in a very similar fashion, but suck in the prey in response to being triggered, operating in very wet conditions or under water.


A Table of Trap Types

GENUS

Common Name

Passive Trap Type

Active Trap Type

Dionaea

Venus Fly Trap

 

steel trap

Drosera

Sundew

 

fly-paper

Pinguicula

Butterwort

 

fly-paper

Utricularia

Bladderwort

 

mousetrap

Darlingtonia

Cobra Lily

pitfall

 

Sarracenia

N. American Pitcher

pitfall

 

Nepenthes

Monkey Cup

pitfall

 


Why do Carnivorous plants trap food?

Carnivorous plants are found throughout the world and in many different habitats - from the acid peat bogs of Britain, where Drosera and Pinguicula grow, to the tropical jungles of southeast Asia, inhabited by the Nepenthes, and the flooded savannahs of Africa, which provide a home for Utricularia.
Many carnivorous plants require permanently wet conditions, as this might suggest, although others live in very dry sandy soils. However, the characteristic common to all their habitats is the lack of nutrients in the soil. By lessening their dependence on the soil for nourishment and by supplementing their diet with food that literally walks or flies in, the carnivores are able to survive where few other plants can. This visiting animal life is an important source of nitrogen - the nutrient which is most easily lost from the soil and which is always rare in soils colonized by carnivorous plants - and nitrogen helps to increase leaf growth and to improve or make possible both flowering and seed production.

What is CITES?

The Convention on International Trade in Endangered Species (CITES) of Wild Fauna and Flora, began on 1 July 1975 where 143 countries banned the trade of an agreed list of endangered species and by regulating and monitoring trade in others that might become endangered.


Written by SteveC