Plant Genus: Dionaea muscipula
Common Name: The Venus Fly Trap
Number of Species: 1
Place(s) found naturally: North & South Carolina in U.S.A.
Dionaea muscipula (Droseraceae)
Introduction: The genus has only one species, Dionaea muscipula, but that does not mean that the genus is in any way dull - for this species is better known as the Venus Fly Trap! Known by possibly billions the world over as ‘the plant the eats bugs’,this infamous plant more than lives up to any expectation a person may have of it. Indeed, D. muscipula is as fascinating to the CP enthusiast of thirty years as it is to a three year old child seeing it for the first time. D. muscipula typically grows in a rossetted fashion, with the traps - the true leaves - held on the end of extended leaf bases known as petioles.
Trap: Commonly abbreviated in CP circles to VFT, the Venus Fly Trap has perhaps the most visually obvious trapping mechanism of all the CPs, yet the physics behind it as astounding as they are subtle. An insect that finds itself in the trap will happily consume the nectar available to it. While moving around, it is likely to touch one of the six trigger hairs - three on each lobe - extending toward the centre of the trap. Should the insect touch two hairs one after the other, or touch the same one twice in quick succession, the trap is very literally sprung. An electrical current passes through the outside of both lobes causing the cells in these lobes to double in length within a second. The result of this is that the concave lobes suddenly become convex, while the spines at the edge of the lobes intersect, producing an effective jail cell. Contrary to popular belief, the trap does not close completely at this early stage, and there is adequate space for any smaller meals to slip away. This is thought to be deliberate on the plant's behalf - there is no point in it consuming a large amount of energy to close the trap and digest the trapped prey if the prey will not provide a comparable amount of energy.
Assuming the prey is sufficiently large it will not be able to escape the clutches of the trap, and there is some evidence to suggest that the struggles of such prey to attempt to do so are 'felt' by the plant, whose response is to close the trap quicker! After several hours, the trap is fully sealed and the plant begins to secrete digestive acids and enzymes into the trap. While these are not too effective on the hard exoskeleton of most insects, the digestive juices are more than capable of 
reducing the insides of trapped prey into nutrient-rich soup, which is readily absorbed by the plant. Once this process has run its course, usually in around seven days, the trap reopens leaving the exoskeleton to be washed away by the next rainfall, ready for its next victim.
Forms: Although I have mentioned that there is only one species in the Dionaea genus, there are many forms. Certain forms are happy to form clumps of plants relatively quickly, while others are slow to reproduce in this way. On the whole growth from seed is a very slow process and it will be around three to five years before a mature plant can be obtained in this way.
The typical form of VFT starts spring by producing traps on the end of short petioles, hugging the ground in a rosetted fashion. As the summer takes hold the petioles become longer and erect, giving the appearance that the trap is reaching up to grab insects out of the air. More probably is that they have evolved to do so to reach up over scrub growth in their native habitat during the summer months. One form, D. muscipula 'Red Rosetted', is noted for its decumbent rossette appearance year round.
The rest of the forms can be broadly categorised in colour and trap mutants. Coloured forms either have especially red trap interiors, or red colour throughout the entire plant. Such colour is difficult to obtain in cultivation due to the high light requirements. Examples of fully red plants are D. muscipula 'Royal Red' and D. muscipula 'Akai Ryu'. There is also an all-green form of D. muscipula, which lacks red pigment totally.
Trap mutants, such as D. muscipula 'Sawtooth' or D. muscipula 'Dentate' amongst others, have traps that differ to the typical form. Usually, the difference is in the spines at the end of the lobes appearing webbed. Some growers have reported dual traps - where two traps are formed on the end of a single petiole - but these are thought to be down to environmental conditions as opposed to plant characteristics as this dual trap phenomenon is generally not repeatable season to season. There has also been some talk of an albino VFT, ghostly white in colour, but it is likely the plant in question was very sick or the photograph itself had been edited.
In the Wild: VFTs are very limited in numbers in the wild, with their native populations in North and South Carolina rapidly being drained for development. However, the plant is very common in cultivation thanks to tissue culture, which is starting to introduce some of the rarer forms to a wider population also. VFTs are listed in Appendix II of CITES, meaning they are under the possibility of future extinction. As such, it is illegal to take plants from the wild and export them to other countries. All VFTs for sale internationally must have the appropriate paperwork to accompany them, proving they were commercially raised. This is in additional to the phytosanitary certificates required in the export and import of most live plant material. However, if you buy a VFT from someone in the UK and you live in the UK no paperwork is normally needed. This is the same with VFTs on sale in garden centres. Incidentally, if you see VFTs for sale in garden centres with the sign asking you not to trigger the traps artificially, please observe this. On the whole, mainstream garden centres give the plants enough to worry about without fingers or sticks being poked at them!
In Cultivation: Caring for VFTs in cultivation is not too difficult, and they require no major difference to general CP care. In the UK, most windowsills receiving a fair degree of light will suitable for their growth. A common VFT soil mixture is 1 part sphagnum moss peat to 1 part sand, and they can be grown on the tray system - taking care to ensure the water is suitable. VFTs require at least three months of cool dormancy, and will tolerate light frosts. Once tip for healthy VFTs is to cut away any flower scape once it is around 2cm (approximately 1 inch) high - the flowers are not very impressive, and the plant can be weakened by flowering. Obviously if you require VFT seeds from your plants, you'll need to leave the plant to flower.
For more plant information check out Rick Walker's CP Database