Toxicodendron radicans, also known as poison ivy is a poisonous plant that is well known for its production of urushiol, a clear liquid compound found within the sap of the plant that causes an itching, or sometimes painful rash in most people who touch it.

Aids to identification

Various mnemonic rhymes describe the characteristic appearance of poison ivy:

1. ”Longer middle stem; stay away from them.” This refers to the middle leaflet having a visibly longer stem than the two side leaflets and is a key to differentiating it from the similar-looking Rhus aromatica (fragrant sumac).

2. ”Leaves of three; let it be.”

3. ”Hairy vine, no friend of mine.” Poison ivy vines are very poisonous.

4. ”Raggy rope, don’t be a dope!” Poison ivy vines on trees have a furry “raggy” appearance. This rhyme warns tree climbers to be wary. Old, mature vines on tree trunks can be quite large and long, with the recognizable leaves obscured among the higher foliage of the tree.

5. ”One, two, three? Don’t touch me.”

6. ”Berries white, run in fright” and “Berries white, danger in sight.”

7. “Red leaflets in the spring, it’s a dangerous thing.” This refers to the red appearance that new leaflets sometimes have in the spring.

8. “Side leaflets like mittens, will itch like the dickens.” This refers to the appearance of some, but not all, poison ivy leaves, where each of the two side leaflets has a small notch that makes the leaflet look like a mitten with a “thumb.”

9. ”If butterflies land there, don’t put your hand there.” This refers to the fact that some butterflies land on poison ivy, since they are not affected, which provides them protection as their predators avoid eating the plant.

10. “If it’s got hair, it won’t be fair.” This refers to the hair that can be on the stem and leaves of poison ivy.

Effects on the body

Urushiol-induced contact dermatitis is the allergic reaction caused by poison ivy. In extreme cases, a reaction can progress to anaphylaxis. Around 15% to 30% of people have no allergic reaction. Most people will become sensitised with repeated or more concentrated exposure to urushiol, as the immune system has been trained to act with greater degree.

The pentadecylcatechols of the oleoresin within the sap of poison-ivy and related plants causes the allergic reaction; the plants produce a mixture of pentadecylcatechols, which collectively is called urushiol. After injury, the sap leaks to the surface of the plant where the urushiol becomes a blackish lacquer after contact with oxygen.

Urushiol binds to the skin on contact, where it causes severe itching that develops into reddish coloured inflammation or non-coloured bumps, and then blistering.

The oozing fluids released by scratching blisters do not spread the poison. The fluid in the blisters is produced by the body and it is not urushiol itself. The appearance of a spreading rash indicates that some areas received more of the poison and reacted sooner than other areas or that contamination is still occurring from contact with objects to which the original poison was spread. The blisters and oozing result from blood vessels that develop gaps and leak fluid through the skin; if the skin is cooled, the vessels constrict and leak less^.

If poison ivy is burned and the smoke then inhaled, this rash will appear on the lining of the lungs, causing extreme pain and possibly fatal respiratory difficulty. If poison ivy is eaten, the mucus lining of the mouth and digestive tract can be damaged. A poison ivy rash usually develops within a week of exposure and can last anywhere from one to four weeks, depending on severity and treatment. In rare cases, poison ivy reactions may require hospitalisation.

Poisons have been used for many purposes across the span of human existence, most commonly as weapons, anti-venoms, and medicines. Poison has allowed much progress in branches, toxicology, and technology, among other sciences.

As early as 331 BC, poisonings executed at the dinner table or in drinks were reported, and the practice became a common occurrence. The use of fatal substances was seen among every social class; even the nobility would often use it to dispose of unwanted political or economic opponents.

In Medieval Europe, poison became a more popular form of killing, though cures surfaced for many of the more widely known poisons. This was stimulated by the increased availability of poisons; shops known as apothecaries, selling various medicinal wares, were open to the public, and from there, substances that were traditionally used for curative purposes were employed for more sinister ends.

Origins of poison

Once the use and danger of poison was realized, it became apparent that something had to be done. Mithridates VI, King of Tim (an ancient Hellenistic state of northern Anatolia), from around 114–63 BC, lived in constant fear of being assassinated through poison. He became a hard-working pioneer in the search for a cure for poisons. In his position of power, he was able to test poisons on criminals facing execution, and then if there was a possible antidote. He was paranoid to the point that he administered daily amounts of poisons in an attempt to make himself immune to as many poisons as he could. Eventually, he discovered a formula that combined small portions of dozens of the best-known herbal remedies of the time, which he named Mithridatium. This was kept secret until his kingdom was invaded by Pompey the Great, who took it back to Rome. After being defeated by Pompey, Mithridates’ antidote prescriptions and notes of medicinal plants were taken by the Romans and translated into Latin.

Pliny the Elder describes over 7000 different poisons. One he describes as “The blood of a duck found in a certain district of Pontus, which was supposed to live on poisonous food, and the blood of this duck was afterwards used in the preparation of the Mithridatum, because it fed on poisonous plants and suffered no harm.”

Present day 

In the late 20th century, an increasing number of products used for everyday life proved to be poisonous. The risk of being poisoned nowadays lies more in the accidental factor, where poison be induced or taken by accident. These problems occur more frequently in children, and poisoning is the 4th most common cause of death within young people. Accidental ingestion’s are most common in children less than 5 years old.

However, hospital and emergency facilities are much enhanced compared to the first half of the 20th century and before, and antidotes are more available.

However, poison still exists as a murderous entity today, but it is not as popular form of conducting murder as it used to be in past times, probably because of the wider range of ways to kill people and other factors that must be taken into consideration. One of the more recent deaths by poisoning was that of Russian dissident Alexander Litvinenko in 2006 from lethal polonium-210 radiation poisoning.

(Source: Wikipedia)

Death Camas, or Zigadenus venenosus is a flowering plant in the genus Toxicoscordion belonging to the Melanthiaceae. It grows up to 70 cm tall with long, basal, grass-like leaves. The bulbs are oval and look like onions but do not smell like onions. The flowers are cream coloured or white and grow in pointed clusters, flowering between April and July. Death camas occurs in some parts of western North America and can be easily confused with edible onions of genus Allium. They tend to grow in dry meadows and on dry hillsides as well as sagebrush slopes and montane forests. 

All parts of the plant are poisonous. It is dangerous for humans as well as livestock, though some poisoned by it have been treated. Alkaloids are responsible for the plants being poisonous; it has been said that eating rich fish or beef broth, grease, or butter may counteract the poison.

Ageratina altissima, also known as White Snakeroot, White Sanicle or Tall Boneset, is a poisonous perennial herb in the family Asteraceae, native to eastern North America. 

They are found in woods and brush thickets where they bloom mid to late summer or fall. There are two different varieties Ageratina altissima var. angustata and Ageratina altissima var. roanensis (Appalachian white snakeroot) they differ in the length of the flower phyllaries and shape of the apices.

Toxicity

White Snakeroot contains the toxin tremetol when the plants are consumed by cattle, the meat and milk become contaminated with the toxin. When milk or meat containing the toxin is consumed, the poison is passed onto humans. If consumed in large enough quantities, it can cause tremetol poisoning in humans. The poisoning is also called milk sickness, as humans often ingested the toxin by drinking the milk of cows that had eaten snakeroot.

During the early 19th century, when large numbers of European Americans from the East, who were unfamiliar with snakeroot, began settling in the plant’s habitat of the Midwest and Upper South, many thousands were killed by milk sickness. Notably, milk sickness was the cause of death in 1818 of Nancy Hanks Lincoln, mother of Abraham Lincoln.

It was some decades before European Americans traced the cause to snakeroot; although today Dr. Anna Pierce Hobbs Bixby is credited with identifying the plant in the 1830s, legend has it that she was taught about the plant’s properties by a Shawnee woman.

Symptoms of White Snakeroot (milk sickness) poisoning

The illness is typically characterised by:

Loss of appetite, Abdominal pain, Violent vomiting, Constipation, Severe thirst, Tremors, Acetone breath, Prostration, Delirium, Coma and Death

The plants are also poisonous to horses, goats, and sheep. Signs of poisoning in these animals include depression and lethargy, hind feet placed close together (horses, goats, cattle) or held far apart (sheep), nasal discharge, excessive salivation, arched body posture, and rapid or difficult breathing.

Actaea pachypoda also known as Doll’s-eyes and White Baneberry is a flowering plant in the family Ranunculaceae.

It is a herbaceous perennial plant its most striking feature is its fruit, a white berry, which give the species its name, “doll’s eyes”. The berries ripen over the summer, turning into a fruit that persists on the plant until frost. Fall foliage color may be yellowish, and is fairly unremarkable.

The berries are highly poisonous, and the entire plant is considered poisonous to humans. The berries contain cardiogenic toxins which can have an immediate sedative effect on human cardiac muscle tissue, and are the most poisonous part of the plant.

Ingestion of the berries can lead to cardiac arrest and death. The berries are harmless to birds, the plant’s primary seed dispersers. Both Native American and settlers made tea out of the roots for relieving pain of childbirth. Settlers also used the plant to improve circulation and to cure headache or eyestrain.

Colchicum autumnale, commonly known as autumn crocus, meadow saffron or naked lady, is a flower which resembles the true crocuses, but flowers in autumn. The name “naked lady” comes from the fact that the flowers emerge from the ground long after the leaves have died.

Colchicum autumnale is the only species of its genus native to the United Kingdom, with notable populations under the stewardship of the County Wildlife Trusts.

Pharmaceutical uses

The bulb-like corms of Colchicum autumnale contain colchicine, a useful drug with a narrow therapeutic index. Colchicine is approved by the US FDA for the treatment of gout and familial Mediterranean fever. Colchicine is also used in plant breeding to produce polyploid strains.

Toxicity

Colchicum plants have been mistaken by foragers for ramsons, which they vaguely resemble, but are deadly poisonous due to their colchicine content. The symptoms of colchicine poisoning resemble those of arsenic, and no antidote is known.

Caladium is a genus of flowering plants in the family Araceae. They are often known by the common name; elephant ear, Heart of Jesus, and Angel Wings.

Cultivation and uses

Several species are grown as ornamental plants for their large, arrowhead-shaped leaves marked in varying patterns in white, pink, and red (somewhat resembling the unrelated coleus) and have been in cultivation in Europe since the late 18th century. The two forms most widely cultivated are called “fancy-leaved” and “lance-leaved”.

All parts of the plant are poisonous. They should not be ingested and may irritate sensitive skin.