Poison ivy

Poison ivy is infamous as a plant that causes skin rashes upon contact, but what people don't realize is that poison ivy is so much more than that. It's a plant that provides nourishment for animals, particularly birds. It is also very beautiful to look at when it's in full bloom, at least from a distance. Despite these two pros, there are many more cons of poison ivy. They cause an infection of the skin with an oil called urushiol that is stored in their sap. The more the oil gets concentrated in one spot, the more that it will grow, like a bubble. The genus name, Toxicodendron, comes from the Latin word "toxicum," which literally means "poison." 

Poison ivy has leaves with three leaflets per leaf, giving it the characteristic appearance that it is known for. The poison ivy plant's origin from creation is unknown, as well as its original purpose. It is possible that the oil in the plant became poisonous when Adam and Eve committed the first sin. That may have been part of the punishment in Genesis when God told Adam that he would have to work the ground in order to make food for his family.

Anatomy
The leaves of the poison ivy plant are almond shaped, and can have many different colors. The younger leaves are usually light green. The mature leaves are usually dark green. In the fall, they will also change their color, just like all other deciduous plants. They can become red, orange, or yellow. Some of the leaves on certain poison ivy plants start out red, then become green, and change back to red again in the fall. There are a few sayings that help people remember what poison ivy looks like. One of the sayings is "Leaves of three, let them be." In some cases, there are berry plants that also have three leaves, which is why there is sometimes a second part to it; "If it's hairy, it's a berry." That way, people don't get the plants confused. There are also a few sayings, including one that has to do with the poison ivy vines that goes, "Hairy vine, no friend of mine." Poison ivy also has berries on it that are a grayish white. The berries are edible for birds, but not humans. "Berries white, run in fright," along with "Berries white, danger in sight" help people remember to be careful of the white berries. The berries are not always white though. There are some species of poison ivy, such as the Western Poison Ivy (Toxicodendron rydbergii) that have red berries.

The poison ivy plant is considered a native, rhizomatous, low shrub, mainly because of its average height of three feet. However, if the sight conditions are favorable, it can take the form of a vine, rather than a shrub. Then it can be up to about ten feet long. The stems are woody and hard, and if it does become a vine and is introduced into a climbing habitat, it will still sprout three leaflets each time that it has reaches the top. Then, it will keep growing leaving leaves sprouted out on the sides, rather than the top. 

Reproduction
As one can recall from the anatomy section, poison ivy does have white, and sometimes red, berries. The berries are poisonous for humans, but they are not toxic for birds. Since the birds eat the berries, they pass through the digestive system in the bird and is expelled in its waste. If the berries do not get fully digested by the bird, they get planted in the ground, and the waste of the bird acts like a fertilizer.

The natural reproduction processes of poison ivy is to reproduce by seed, as well as vegetatively by rhizomes. One of its reproduction processes is through sexual reproduction. Before they are berries, the grayish white berries of poison ivy are flowers. The flowers bloom from May to July, and the mature fruits/berries are produced from August to November. When they do becomes little berries, or technically fruits, two things can happen to them. One is that they get eaten by the birds and distributed in their waste. The fruits that are not consumed remain on the plant through winter. At the end of the winter, they are deposited beneath the parent plant. If the soil is composed of mainly bare minerals, it is conductive to the germination and establishment of new poison ivy plants. 

Another way that poison ivy reproduces is through vegetative reproduction. Leafy shoots are produced by rhizomes at the basal stem of the plant. They can extend up to about seven feet from the parent plant. This can form an extensive network of poison ivy, producing a thicket of it in just one place. This usually happens in the places that get disturbed by construction. Just one thicket of poison ivy can simply be a clone that was under favorable conditions. It can also be a plant that simply germinated in the regular sexual reproduction process. 

Ecology
Eastern poison ivy (T. radicans) is located mainly on the eastern side of North America, whereas Western poison ivy (T. rydbergii) is the species found on western region. Closely related species of poison oak can also be found in the U.S.

Poison ivy can be found in places such as woods, forests, and mountains up to about five thousand feet. It is a somewhat shade tolerant plant, and grows mainly on the forest floor, around the height of four to ten inches. It also grows as a shrub as high as four feet, and as a vine that grows up various supports. The older vines often send out limbs at a rather lateral angle that can possibly be mistaken for tree limbs. It can also grow along the edge areas of a forest or a development of houses, as well as in exposed rocky areas and open fields. Also, if there is some sort of disturbance in its natural habitat, such as a construction project that is being done at the expense of the forest, the poison ivy will grow there also. That is one of the reasons that it is so common in suburban and exurban areas where there were probably forests before, such as the New England, the Mid-Atlantic and Southeastern areas of the United States. Another strange thing about poison ivy is that it has intolerance to certain abnormalities. There was a test done to show the effect of fire on fuel loads and pest species. There were more poison ivy plants extinguished with herbicide applications on the burned lots, rather than the unburned. The urushiol had transformed into a gaseous state, and something about the lack of urushiol caused the herbicide applications to kill them off better than when they still had the urushiol

Toxicity
One of the things that poison ivy is most known for is the effect that it has on human skin. This effect comes from an oil called urushiol. When the oil comes in contact with the skin it causes a rash to form. There are three different ways for the oil to reach the skin. One of them is through direct physical contact. If you touch a plant that contains urushiol, it will react with the skin, causing a nasty rash. Another way is through indirect contact. Since it is an oil, urushiol can stick to almost anything. If it gets stuck to something like an inanimate object or the fur of a pet, it can be easily dispatched onto a human's skin, even if they had no direct contact with the plant. The third and final way for the oil to reach the skin is through airborne contact. If you find a poison ivy plant and decide that the best way to dispose of it is to burn it, then think again. The burning of a plant that has urushiol in it will result in the oil going airborne, thus contaminating the area around which it was burned, as well as those who might have burned it. The results of these contacts with urushiol can be very nasty. There are recorded instances of people who get poison ivy from the roots of poison ivy, as well as trimming hedges with poison ivy in them. The results are not beautiful. 

People get infections from poison ivy when there is direct contact with the plant. Some people, about 15% to 30% have no reaction to poison ivy. This is do to the fact that an urushiol-induced contact dermatitis is an allergic reaction. some people don't have a reaction because they aren't allergic to the infection caused by urushiol. If the plant has been damaged in any way, there could be infection from the plant just by a brush up against it. This is mainly due to the fact that there is a poisonous oil in the sap called urushiol. One can also get an infection from it when certain objects become contaminated. When someone is infected with poison ivy, the first symptom of infection is the itching of the skin. Later, there is inflammation and the skin becomes red. If there was more contact in the situation, there will be oozing pores that will develop due to the urushiol. When the oil comes in contact with the skin, the blood vessels begin to develop gaps where the fluid will leak through the skin, and the infection will cause blisters and the pores will develop. If the area where the infection took place is cooled down, there will be less infection, due to the fact that your pores will shrink, and less will get through the skin. It does not take much for the plant to cause a rash. It only takes as much as one nanogram of urushiol to cause an infection. A person that comes in contact with poison ivy usually receive about 100 nanograms of urushiol on average. What's more, it only takes a fourth of an ounce of urushiol to cause a rash on every single human being in the earth. The amount of urushiol that could cover the head of a pin is enough to make 500 people itch. Certain specimens of urushiol that are centuries old have been known to cause dermatitis in sensitive people. Urushiol usually stays active from about one to five years on either a living or a dead plant. 

The rash caused by urushiol can also occur inside the body. If someone burns a poison ivy plant, and the smoke from the fire gets inhales, the infection can appear on the lings, causing severe issues with the respiratory tract and lungs due to the rash. If someone eats the poison ivy, the infection and the rash will occur in the digestive tract. Some people are more sensitive to the infection from urushiol than others, and since urushiol is a highly active oil, people can still get infections from the stems and leaves of dead plants. If someone is very sensitive to the reaction that can be caused by poison ivy, they could possibly get a similar rash from mangos, which are in the same family as poison ivy, and also contain urushiol in their sap and the skin of the mangos.