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Identification and Precautions for Dealing with Wild Poisonous Plants

Poisonous Plants are Prevalent in Our Country as Well. Let's Learn How to Recognize Them and Understand the Potential Dangers They Pose.

by BioGrow

The poisonous plants are found in nature and are also abundant in our country. For this reason, it becomes important to recognize them and take the right precautions.
We have already talked about many wild plants that have beneficial properties. Many of these are edible or useful for specific preparations. Among the most well-known and loved by enthusiasts are: St. John’s wort, dandelion, wild mallow, purslane, borage. Now let’s see the most widespread and dangerous poisonous plants distributed in Italy and try to recognize them through a photo gallery. The risk of encountering them, perhaps during a mushroom hunting trip, is high. Therefore, it’s good to be able to identify them.

Furthermore, let’s discover the toxic effects that they can cause in case of occasional ingestion, something that unfortunately cannot be ruled out.

Poisonous plants present in Italy

Aconitum napellus

Poisonous plants - Aconitum napellus

Aconitum napellus

The aconitum napellus (Aconitum napellus) is a perennial herbaceous poisonous plant belonging to the Ranunculaceae family.
It ranges in height from 50 cm to 2 meters and is a rhizomatous geophyte, meaning it carries its buds underground.
Aboveground, it has an upright shape, with a robust stem, green in color, and lightly branched.
It has two types of leaves. The basal leaves have petioles, dark green on the upper side, and whitish on the lower side. These leaves have a glabrous leaf blade, lanceolate in shape, and dimensions of about 8 cm wide and 12 cm long.
Then there are the cauline leaves, smaller in size, with incised blades and narrower lobes.
The inflorescence consists of a terminal raceme in the shape of a spike, with purple flowers.

Risks of aconitum napellus

This plant is highly poisonous and was historically used for homicidal purposes. In case of ingestion, it causes paresthesia within 30 minutes, associated with tingling in the oral cavity. Then the symptoms progress, causing an anesthetic effect, muscle weakness, respiratory failure, and cardiac fibrillation. It contains various toxic alkaloids, including aconitine, one of the most potent plant toxins. This alkaloid acts on sodium channels, keeping them open, thus causing cardiac arrest, as the heart needs rhythmic opening and closing of these channels. Just a few grams of the plant are enough to risk death.
Its active compounds are easily absorbed through the skin, so even simple contact can cause serious problems. There are no specific antidotes, so if you recognize it, stay away.
In China, it is considered one of the leading causes of vegetable poisoning, as it is used (we don’t know how) in traditional medicine, despite being classified as a poisonous plant.
In our country, it is quite common along the Alpine arc, in forests, meadows, and pastures, at altitudes between 600 and 2600 meters.

Holly

Poisonous plants - Ilex aquifolium

Ilex aquifolium

Another toxic species for humans is the well-known holly (Ilex aquifolium), also known as common holly, English holly, or European holly. It’s a poisonous shrub belonging to the Aquifoliaceae family. It can grow up to 10 meters in height and has a pyramid-shaped crown. It has smooth gray bark with greenish branches. The leaves are dark green and shiny, with the characteristic spiny margins. The flowers are white or pink, gathered in small axillary clusters. The fruits, which ripen in winter months, are bright red berries. Holly is native and widespread throughout our country. It’s also cultivated for decorative purposes in nurseries and is associated with Christmas traditions. This is why it’s commonly found in gardens shaped as hedges.

Risks of Holly

Holly poses a significant risk to children, who are naturally attracted to its colorful red berries.
Its toxicity is due to the presence of saponins in the berries, but it also contains traces of theobromine, ilicin, and ilixanthin.
In case of berry ingestion, gastrointestinal symptoms occur, such as nausea, vomiting, and diarrhea. These symptoms usually appear after consuming at least 2-3 berries.
It is not a lethal species.

Deadly Nightshade

Poisonous plants - Atropa belladonna

Atropa belladonna

The deadly nightshade (Atropa belladonna) is a flowering plant belonging to the Solanaceae family. It is part of the same family as other well-known plants like tomatoes, eggplants, peppers, potatoes.
Deadly nightshade is a perennial poisonous plant.
It has a large fleshy root, from which a robust and branched stem emerges, which can reach up to 1.5 meters in height. The leaves are simple, with a petiole, and are oval-lanceolate in shape.
It has an unpleasant odor caused by glandular hairs present on both the stem and leaves.
This poisonous plant blooms during the summer. The flowers are bell-shaped and dark purple in color. The flowering period is between the months of April and August. It is a very common poisonous plant in our countryside. It prefers cooler places, such as the edges of hedges or forests, and areas near rivers.
The popularity of deadly nightshade, compared to other poisonous plants, is due to its presence in ancient Greece. It was used to administer the death penalty through poisoning. The most famous victim of deadly nightshade poisoning was the philosopher Socrates.

Risks of Deadly Nightshade

Ingestion of the fruits causes severe symptoms, beginning with a decrease in sensitivity. This is accompanied by forms of psychotic delirium and intense thirst followed by vomiting. In cases of more serious poisoning, there can be convulsions, circulatory disturbances, respiratory paralysis, and therefore death.
These effects are due to the presence of alkaloids such as atropine, scopolamine, and hyoscyamine, which the plant synthesizes in the roots and then transports to the rest of the plant, especially in the fruits.
The most at-risk subjects are children, who can confuse belladonna berries with those of blueberries.
Due to the symptoms it causes, belladonna is also known as the witch’s herb, and its use is associated with satanic rituals.
Belladonna poisoning should be treated with immediate gastric lavage and activated charcoal, which help eliminate the poison quickly. To slow down its absorption, sedatives or cold baths should be administered, which can alleviate the hyperthermia that occurs.
Fortunately, in our country, it is considered a rare species, found in woods and clearings from lowlands to altitudes of 1400 meters. Sicily is one of the regions where the plant is more prevalent and is known as sulatra.
Although counted among poisonous plants, when properly treated, belladonna is used in herbal medicine. The leaves, in fact, have various therapeutic properties, such as anti-hemorrhoidal, soothing, and antimuscarinic effects.

Greater Hemlock

Conium maculatum

Conium maculatum

Among poisonous plants, the worst of all is greater hemlock (Conium maculatum), an herbaceous plant belonging to the Apiaceae family.
This plant, also known as hemlock, has a large fleshy root of white color. It is easily recognizable, also because of its unpleasant odor, which resembles cat or rat urine, especially when the stem is broken.
The stem can reach up to two meters in height. It is hollow inside, smooth on the surface, and marked along its entire length by reddish-purple spots.
The leaves are large, averaging 50 cm in length and 40 in width. Their shape is triangular, and they are divided inside into many small leaflets.
The flowers make their appearance on the plant starting from the second year.
They are white, and their inflorescence is umbrella-shaped.
The flowering period is between the months of April and August.
It is a very common poisonous plant in our countryside. It prefers cooler areas, such as the edges of hedges or woods, and near rivers.
The popularity of hemlock compared to other poisonous plants is due to its introduction in ancient Greece. It was used there to administer the death penalty through poisoning. The most famous victim of hemlock poisoning was the philosopher Socrates.

Risks of Greater Hemlock

The high toxicity of the plant is due to the presence of five alkaloids: coniine, conhydine, pseudoconhydine, methylconicine, and coniceine.
These toxic alkaloids cause symptoms of poisoning typical of this class of neurotoxins. These include excessive salivation, intense muscle tremors, widespread spasms, and death from respiratory collapse.
While direct poisoning is a rather rare hypothesis, mainly due to the nauseating odor of the plant, cases of indirect poisoning are more frequent. For example, a bird like the quail can eat hemlock and accumulate its toxic principles in its own flesh.
Another risk associated with hemlock is that it, like other similar species, can be dangerously confused with common non-toxic plants. An example is wild parsley (hence the common name of false parsley) or chervil.

Common Daphne

Daphne mezereum

Daphne mezereum

The common daphne (Daphne mezereum) is a poisonous plant belonging to the botanical family Thymelaeaceae. This shrub, with a bushy habit, is no more than 70 cm tall. It is also called the stick flower because of its ability to produce flowers and fruits on seemingly bare and dry branches. It has a woody stem with a bark that is gray to pink in color. The lateral branches are substantial and have small protuberances left from the leaves that fell in the previous season. The inflorescence of this poisonous plant consists of several violet-colored flowers grouped in sets of three at the axils of the leaves. The fruits are poisonous berries that are red in color, with a diameter of 9-10 mm.

Risks of Common Daphne

Common daphne poisoning symptoms evolve starting from abdominal pain, vomiting, and hypothermia. In the case of ingestion of large quantities, difficulty in breathing is added. The symptoms are somewhat subtle, as they can appear after several hours, causing possible confusion about the original cause. However, cases of lethal poisoning are very rare.

Bittersweet Nightshade

Solanum dulcamara

Solanum dulcamara

The bittersweet nightshade (Solanum dulcamara) is a plant belonging to the Solanaceae family. Although not one of the most poisonous plants in our spontaneous flora, it is worth paying attention to. This is because it is one of the plants with which children most easily poison themselves. This plant produces red fruits, very similar to those of currants, with a sweet-bitter taste, hence the Latin name. It is a climbing plant with a bushy habit, i.e., shrubby with drooping leaves that lean on other plants for support.It is a very common species in our country, and it is present from lowlands up to 1500 meters, preferring Mediterranean scrub areas and woods. The berries of bittersweet nightshade contain alkaloids, whose concentration decreases when the fruits ripen. In addition to alkaloids, the fruits contain high doses of saponins and calcium oxalate, elements that can lead to intestinal disturbances.

Risks of Bittersweet Nightshade

The risk of poisoning from this species is due to the consumption of immature berries, which contain a high amount of steroidal alkaloids, such as solasodine. However, these types of alkaloids are currently used in experimental pharmacology to treat certain skin tumors. A potentially dangerous quantity for humans is ten berries.

Black Nightshade

 Solanum nigrum

Solanum nigrum

The black nightshade (Solanum nigrum) is one of the most common wild poisonous plants. Like belladonna, it belongs to the Solanaceae family. It is also known as the weed of gardens. As the name suggests, it has a very high reproductive capacity, especially if the black fruits are crushed and the seeds dispersed. Morphologically, it is a plant very similar to eggplant. Its stem is highly branched, woody at the base, with a smooth surface and a musky odor. The leaves are arranged along the stem alternately, with variable shapes from oval to lanceolate. The flowers are white, and from these flowers, the fruits develop, typical berries that are initially green and then glossy black in color. The berries of the black nightshade are small and grouped in small but numerous clusters.

Risks of Black Nightshade

The toxic principle of the plant is the tassin, a mixture of highly toxic terpenic alkaloids for the heart. A few leaves of the plant are lethal to humans, as there are no specific antidotes. However, it should be noted that this plant has a very high value in modern pharmacology. Its bark contains taxol, a diterpene that has been used for a long time in the production of effective drugs for the treatment of breast cancer. In the past, the wood of the black nightshade was used to make bows, even in ancient times. For example, the wood of the Similaun Mummy was made of black nightshade. This tradition continued until more recent times when synthetic fibers replaced black nightshade wood for bow production.

Poisonous Lettuce

Poisonous plants - Lactuca virosa

Lactuca virosa

The poisonous lettuce (Lactuca virosa) is a herbaceous plant belonging to the botanical family Asteraceae. We can consider it as a wild and non-edible relative of Lactuca sativa, the classic lettuce. Its appearance is similar to that of edible lettuce, although it is much more prickly and can reach up to 1.5 meters in height. It is a widespread poisonous plant in uncultivated soils. It is also found along old walls and roadsides, from lowlands up to 800 meters in altitude. The toxicity is due to the very bitter white latex contained in the aerial parts of the plant. This latex is composed of sesquiterpene lactones, namely lactucin and lactucopicrin, which are toxic to humans. In ancient times, this latex was dried and used in medicine as a sedative, a substitute for opium.

Oleander

Nerium oleander

Nerium oleander

The oleander tree (Nerium oleander) is a shrub species belonging to the family Apocynaceae. It is an evergreen shrub with vigorous growth, typical of the Mediterranean region. In fact, it can be found as an ornamental plant in all Italian regions. To recognize it, just look at its typical lanceolate leaves with a leathery texture and dark green color. Its distinct and splendid flowering is also unmistakable, with flowers of varying colors, white, pink, or red. Its toxicity, classifying it as a poisonous plant, comes from the high content of cardiac glycosides, highly toxic substances. The toxic active principle is called oleandrin, which can maintain excellent stability in the soil, being detectable even 300 days after leaf fall.
Those who practice home composting might wonder whether to add oleander foliage to the compost or not. Since oleandrin is not absorbed by plants, we can say that its presence in the compost does not make it toxic. Nevertheless, since it doesn’t have berries, the risk of oleander poisoning is quite low. Moreover, the plant contains saponins, which in case of ingestion promote vomiting and thus the elimination of ingested parts. Furthermore, its very bitter taste does not encourage ingestion. In any case, pay attention to children, who are always at risk due to their habit of ingesting anything.

Yew

Poisonous plants - Taxus baccata

Taxus baccata

We conclude our overview of poisonous plants by talking about the yew (Taxus baccata), a tree belonging to the order Coniferales and the family Taxaceae.
This tree is also known as the tree of death, and it is indeed one of the quintessential poisonous plants. Just think that its name comes from the Greek word toxon, from which the term toxicology derives.
In our country, it is present in various areas, preferring humid and cool places with limestone soil. The yew is an evergreen tree. It is characterized by very slow growth, but at full maturity, it can reach up to 20 meters in height. It has low branches and takes on a globular shape. The leaves are the most poisonous part of the plant. They have a linear shape, slightly curved, about 3 cm long, dark green on the upper side, lighter on the lower side. They are arranged spirally on the branches, in two opposite rows.
It is a zoophilic plant, meaning it relies on animals for reproduction. For example, birds eat the arils, digest them without getting poisoned, and disperse the seeds through their feces, giving rise to new trees. However, for other animals, yew seeds are lethal. Horses, for instance, are one of the most vulnerable species. Another immune animal species is goats.

Areas Where Yew is Present

  • Puglia, in the Gargano forest;
  • Island of Elba, near Monte Capanne;
  • Abruzzo, on some mountains in the province of L’Aquila;
  • Sora, in the province of Frosinone;
  • in the Nebrodi Park, a protected area in Sicily;
  • in the protected natural area of “Nuclei di Taxus Baccata” in the province of Arezzo;
  • Sardinia, in the protected area called “Sos di Nibberos,” covering an area of about 7 hectares within the Monte Pisanu forest reserve.

Risks and Uses of Yew

The toxic active principle of the plant is taxine, a mixture of highly toxic terpenic alkaloids for the heart. A few leaves of the plant are lethal to humans, as there are no specific antidotes.
However, it should be noted that this plant has a very high value in modern pharmacology. Its bark contains taxol, a diterpene that has been used for a long time in the production of effective drugs for the treatment of breast cancer.
In the past, the wood of the yew was used to make bows, even in ancient times. For example, the wood of the Similaun Mummy was made of yew.
This tradition continued until more recent times when synthetic fibers replaced yew wood for bow production.

Clarifications

We have come to the end of this extensive overview of poisonous plants. Naturally, our list cannot be exhaustive. If you are interested in the topic and want to delve further, we invite you to read one of the many specific books that you can find here.

Further Reading

  • PubMed – Hum Exp Toxicol: “Toxicity effects of Nerium oleander, basic and clinical evidence: A comprehensive review” – The article provides a comprehensive review of the toxic effects of Nerium oleander, a plant frequently grown in gardens and public areas. The study delves into the clinical evidence and basic mechanisms of its toxicity.
  • PubMed – J Forensic Sci: “Fatal ingestion of Taxus baccata: English yew” – Autopsy revealed the presence of plant matter visually identified as leaves from Taxus baccata – the English Yew. The study further delves into the isolation of alkaloids from the plant material and their identification in the decedent’s blood.
  • PubMed – BMJ Case Rep: “Wild lettuce (Lactuca virosa) toxicity.” – Wild lettuce (Lactuca virosa) can cause toxic effects when consumed. The plant grows in northern Iran, and some locals consume it, unaware of its adverse side effects.
  • MDPI – Toxins: “Toxicological Properties of the Triterpenoid Saponins from Conium maculatum Extracts” – This research delves into the toxicological properties of triterpenoid saponins isolated from Conium maculatum, highlighting their potential toxic effects.
  • Queensland Poisons Information CentreBlackberry nightshade. Botanical name: Solanum nigrum, Solanum americanum: An annual or perennial soft wooded herb to about 60cm often found growing as a weed in gardens or waste areas.
  • PubMed – J Toxicol Clin Toxicol: Toxicity of nightshade berries (Solanum dulcamara) in mice: Ripened nightshade berries (Solanum dulcamara) are commonly ingested in Minnesota, especially by children. Limited information on berry toxicity leads to conservative treatment using ipecac syrup. A study on mice exposed to unripened berries showed gastrointestinal changes consistent with solanine toxicity. However, ripe berries didn’t cause toxicity. Aggressive treatment for ingested ripe S. dulcamara berries seems unnecessary.

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