Venus Flytrap, also known as Venus's Flytrap
The Venus Flytrap is among a group of plants known as Carnivorous plants. There are various types of carnivorous plants, including flowering plants and fungi which prey and feed upon small animals and insects. Such species are sometimes referred to as insectivorous plants.
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Governor Arthur Dobbs of North Carolina was the first person to describe the plant. He named it "Fly Trap Sensitive". In 1760 he communicated about the discovery of the plant's peculiar ability to close and trap objects, to Mr. P. Collinson of England. Later, Mr. J. Bartram of Philadelphia sent specimens known to him as "Tipitiwitchet," to Mr. P. Collinson. The species was first described among the scientific community in 1768 by the American botanist J. Ellis in letters to Linnaeus providing a substantial description of the structure and functions of the leaves, suggesting even the insectivorous nature of the species. Linnaeus declared it the most wonderful of plants, Miraculum Naturae. Linnaeus presumed the plant exhibited extreme sensitivity, in which insects were accidentally captured and subsequently allowed to escape.
"But the plant, of which I now enclose you an exact figure, with a specimen of its leaves and blossoms, shews, that nature may have some view towards nourishment, in forming the upper joint of the leaf like a machine to catch food: upon the middle of this lies the bait for the unhappy insect that becomes its prey. Many minute red glands, cover its inner surface, and which perhaps discharge sweet liquor, tempt the poor animal to taste them; and the instant these tender parts are irritated by its feet, the two lobes rise up, grasp it fast, lock the row of spines together and squeeze it to death. And, further, lest the strong efforts for life, in the creature thus taken, should serve to disengage it, three small erect spines are fixed near the middle of each lobe, among the glands, that effectually put an end to all its struggles. Nor do the lobes ever open again, while the dead animal continues there."
The letter which contained inaccuracies did not convince Linnaeus of the plant's carnivorous nature, he believed rather, that the insects were released, and trapped merely due to oversensitivity, being such the case with Mimosa pudica.
Ellis arrived at incorrect conclusions about the functions in the plant, including the three erect spines which were later discovered to be trigger hairs on the inner surface of the trap, and a view shared by Erasmus Darwin, botanist and grandfather of Charles Darwin, who wrote,
"In the Dionaea muscipula there is a still more wonderful contrivance to prevent the depredations of insects: the leaves are armed with long teeth, like the antennae of insects, and lie spread upon the ground around the stem, and are so irritable, that when an insect creeps upon them they fold up and crush or pierce it to death."
However the insectivorous nature of the plant was more elaborately investigated by Charles Darwin and described in his book, Insectivorous Plants (1875).
Charles Darwin observed the plant during its digestive state, noting the abundance of the secreted fluid. Making a small opening at the base of one lobe which contained a large crushed fly, the secretion continued to run down the rootstalk a total of nine days, during which the plant was under steady observation.
The required time for digestion is approximately ten days to complete, after which the leaf reopens. Each leaf, or trap, can capture an average of three or four insects during its life span after which it ceases to function. Otherwise, when the trap has been triggered without successful capture of prey it can open and close many more times.
Ellis named the plant Dionaea. The origin of the name Dionaea has its origin in Greek and Roman mythology. In Greek, Dione is the mother of Aphrodite and at times used as an alternative name for the goddess of love. To the Romans, Venus was the goddess of love.
The Venus Flytrap is a native perennial found near the borders of coastal North and South Carolina around swampy bogs. Seldom ever does the flytrap survive well after relocation from its wet native habitat. Often flytraps are found in the presence of other carnivorous plants such as Sundews, Butterworts, Bladderworts and Pitcher Plants. The flytraps inhabit relatively level areas, and tend not to be found where depressions lie due to excess water. They thrive in damp soil, although it has been observed that during relatively dry periods there is no apparent harm to the plants.
Several methods are employed among carnivorous plants to trap their prey. Venus Flytrap's method is different from many other carnivorous plants and referred to as a "Mechanical Trap," specifically a "snap trap". Each leaf has two lobes, standing at rather less than a right angle to each other. The typical angle formed by the lobes is 40 to 50 degrees.
The upper surfaces are covered with minute circular sessile glands. The prey is trapped by rapid closure of the lobes around the insect when it touches one of the three sensory hairs, or fine-pointed bristles. In rare instances there may be as many as four trigger hairs on each surface. The trap has been compared to a hinge but this is inaccurate because a hinge has an articulated joint. The trap has none. It is equipped with bristles that are sometimes referred to as cilia. There are two types of glands,
- Alluring glands, which produce a sugary substance which has a pleasant odor to attract insects and arranged along the outside margins of the trap. It has been argued that this arrangement is by design to prevent the smallest insects from tripping closure of the trap, conserving the plant's effort and energies for more desirable prey. Therefore, any insect which is less than ¼ inch in length is too short, but can freely dine on the nectar. In the event a small insect has triggered closure and escapes, the trap will reopen after about a 24 hour period.
- Digestive-absorptive glands, are conspicuously red in coloration due to a pigment present in the cell fluid: Anthocyanin. If the prey that becomes imprisoned is the correct size for the trap, digestion will occur without any decay. However, the formic acid present in the digestive secretions and process is believed to be a bactericide. Inappropriate objects, such as fat which is placed in the trap, will cause the trap to turn black and decay instead of opening. However, the death of a trap does not spell demise for the entire plant as new traps are in the process of forming during the growing season (70°-100°F), at the base of the rosette.
This reaction, snapping shut and the leaf closing around the insect, occurs in about half a second in normal daytime temperatures. The spikes interlock, and the insect is trapped. After suitable prey is captured, within thirty minutes a narrowing phase begins in which the lobes become tightly pressed together and the outline of captured prey is visible while soft-bodied insects are crushed. This is followed by the release of digestive enzymes within the trap's interior whilst a protective seal is produced just below the marginal spines. If the insect has not been crushed by the lobes, it is likely the insect drowns in the digestive fluids.
The leaf then forms what may be referred to as a "temporary stomach" of sorts. With the insect imprisoned, the Flytrap's glands pour out a red acidic secretion or "sap" containing an enzyme that will dissolve the soft body parts. This digestive enzyme is similar to that which is produced by the leaves of the Sundew plant.
The Venus Flytrap grows from a bulb-like rootstalk and bears slender flower stalks which reach about a foot in height, producing a corymbs of white flowers which sprout in May and bloom in June. The stalk may bear between 1-15 white flowers. Each flower consists of 5 green sepals, 5 white petals, typically 15 stamens and 1 compound pistil. The leaves grow two to eight inches long and located at the base of the plant in a spreading rosette.
During the changing seasons the plant takes on varying characteristics. During the spring, leaves tend to be green with broad petioles which lateral extensions are referred to as "wings". Red coloration is limited or absent, if it is present, it is restricted to the glands on the inner surface of the traps. When late spring becomes summer, the spring leaves are terminated by flowering. When flowering has completed, the summer leaves are produced which are as long or longer, much more narrow and almost wingless. The summer leaves produce the largest traps which tend to grow vertically. With the onset of fall, winter-like leaves are produced which are the smallest. Frost may kill the leaves during the winter. Those which survive winter, tend to be prostrate and about the size of spring to summer leaves.
The bright red coloration in some flytraps seems to be influenced by its exposure to light. Though genetic factors play a role, flytraps thrive well in intense light with most of the plants developing the deep red maroon coloration in the traps, however, when there is insufficient lighting, the plants tend to develop with less healthy characteristics and remain a green pigmentation throughout. Although light contributes to their overall preferred health, direct sunlight is discouraged when cultivated in enclosed containers.
Venus Flytrap is the only known species in the genus Dionaea, therefore making it monotypical.
| Kingdom | Plantae – plants |
| Subkingdom | Viridaeplantae – green plants |
| Infrakingdom | Streptophyta – land plants |
| Division | Tracheophyta – vascular plants |
| Subdivision | Spermatophytina – seed plants |
| Infradivision | Angiospermae – flowering plants |
| Class | Magnoliopsida |
| Superorder | Caryophyllanae |
| Order | Caryophyllales |
| Family | Droseraceae – sundews |
| Genus | Dionaea (J. Ellis) – Venus flytrap, Venus fly trap |
| Species | Dionaea muscipula (J. Ellis) – Venus fly trap, Venus flytrap |
