Venus flytrap (Dionaea muscipula)
|Size||Leaf blade length: up to 12 cm (2)|
Trap length: up to 4 cm (2)
Classified as Vulnerable (VU) on the IUCN Red List 2006 (3), and listed on Appendix II of CITES (4).
The Venus flytrap is perhaps one of the best-known and most awesome plants. Its leaves are modified in an extraordinary way in order to feed on insects, although it does still obtain energy from the sun. The plant is an innocuous looking rosette (5), but the leaf blades terminate in distinctive bivalve traps with sharply toothed edges (2). The outside of the traps is generally green whilst the insides have red pigment that varies in shade depending on the age of the trap; on the edge of each lobe there are 14-20 teeth that point radially from the trap (2) (6). The flower stalk is devoid of leaves (known as a scape) and can reach up to 30 cm tall (2). In season, small white flowers are born with faint green veins; the seed capsules are flat and contain a single, shiny black seed (2).
Endemic to North America, the Venus flytrap is found in south-eastern North Carolina reaching into north-eastern South Carolina (2). An additional small population has been found in northern Florida although it is thought to be derived, by some method, from the Carolina populations (2).
The Venus flytrap inhabits pine savannahs, associated with peaty, sandy soils and fairly constant moisture (2).
The Venus flytrap, as its name suggests, is able to catch and digest insects. Insects are attracted to the small traps by the bright pigment and the nectar secreted by a row of glands situated just below the teeth of the trap (5). On the inner lobes there are usually three trigger hairs and if an insect lands on a lobe and brushes against two of these hairs within a short space of time, the trap with snap partially shut with a speed that amazes onlookers (5). It is believed that this phenomenon is achieved by the rapid acid growth of cells on the trap's outer surface (2) (6). The teeth are now interlocked, preventing larger prey from escaping but the trap must close further to produce a tight seal if the prey is to be digested (2). It is thought that this slower closing process is triggered by chemical and mechanical signals released by the struggling prey, and is accomplished by localised areas of cell growth, such as at the hinge (2). The teeth are now pointing outwards and the trap is sealed allowing digestion to begin using digestive juices released from glands within the inner trap wall; the process of digestion usually takes 7 to 10 days (2). The trap will then open and is able to begin the process again; a single trap will only undertake 3 - 4 such digestion processes, after which time it merely photosynthesises (2).
The Venus flytrap is a perennial plant, which produces flowers from mid-May to the beginning of June; the method of pollination is not yet understood and whilst cross-pollination seems likely, self-pollination may also be possible (2). It is thought that seeds are dispersed in water, or by birds that accidentally pick up seeds in the muddy habitat (2).
There is an extremely large demand for carnivorous plants throughout the world, due to their fascinating features. The illegal collection of large numbers of Venus flytraps still occurs for export mainly to Europe; in 1993 it was estimated that around 500,000 plants were collected (2). The destruction of its habitat is another major threat to the survival of the Venus flytrap (2).
The Venus flytrap is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), which regulates international trade in wild plants of this species. In addition, it is protected by law in the United States where it is illegal to collect Venus flytraps from the wild (2). The recent success of tissue culture to allow the cultivation of a large number of plants is hoped to lesson the demand for wild-collected flytraps (2). A concerted effort is being made to conserve this fascinating plant, a species that Darwin himself called the 'most wonderful plant in the world' (2).
For more information on the Venus flytrap see:
- Schnell, D.E. (2002) Carnivorous Plants of the United States and Canada. [2nd edn.] Timber Press, Oregon.
BBC Wildlife Finder:
Authenticated (08/06/2006) by Barry Rice, Director of Conservation Programs, The International Carnivorous Plant Society.
- Endemic: a species or taxonomic group that is only found in one particular country or geographic area.
- Perennial: plants that live for at least three seasons; after an initial period they produce flowers once a year.
- Photosynthesis: metabolic process characteristic of plants in which carbon dioxide is broken down, using energy from sunlight absorbed by the green pigment chlorophyll. Organic compounds are made and oxygen is given off as a by-product.
- Scape: in plants, a leafless flower stalk.
NatureServe Explorer: (June, 2006)
- Schnell, D.E. (2002) Carnivorous Plants of the United States and Canada. Timber Press, Oregon.
IUCN Red List (June, 2006)
CITES (February, 2003)
- Attenborough, D. (1995) The Private Life of Plants. BBC Books, London.
- Rice, B. (2006) Pers. comm.