1. Oleander, Nerium (Nerium oleander, synonym: Nerium odorum)
2. Poison hemlock (Conium maculatum, synonym: Cicuta maculata)
3. Yellow oleander; Be-still tree (Thevetia peruviana, synonym: Cascabela thevetia)
4. Yellow bell, Golden trumpet (Allamanda cathartica)
5. Castor oil plant (Ricinus communis)
6. Angel’s trumpet, Anglels’ tears (Brugmansia suaveolens)
7. Devil’s trumpet (Datura metel, synonym: Datura alba)
8. Downy thorn apple (Datura innoxia, or Datura innoxia)
9. Jimson weed, Devil’s snare (Datura stramonium)
10. Night-blooming jasmine, Queen of the night (Cestrum nocturnum, synonym: Cestrum parqui)
11. Sandbox tree (Hura crepitans, Hura brasiliensis)
12. Buddha belly, Gout plant (Jatropha podagrica)
13. Purging nut tree, Physic nut (Jatropha curcas)
14. English ivy (Hedera helix)
15. Lily of the valley (Convallaria majalis)
16. Pencil cactus (Euphorbia tirucali)
17. African milk tree (Euphorbia trigona)
18. Crown of thorns (Euphorbia milii)
19. Indian spurge tree (Euphorbia neriifolia)
20. Christmas plant (Euphorbia pulcherrima)
21. Lantana (Lantana camara)
22. Crown flower, giant milkweed, swallow wort (Calotropis gigantea, synonym: Asclepias gigantea)
23. Sodom apple (Calotropis procera)
24. Sago palm, King sago palm (Cycas revoluta)
25. Bird of pardise (Strelitzia reginae)
26. Rhododendron, Azalea (Rhododendron sp.)
27. Bigleaf hydrangea (Hydrangea macrophylla)
28. Tulip – Tulip (Tulipa sp.)
29. Daffodil (Narcissus sp.)
30. Belladonna lily (Amaryllis belladonna)
31. Barbados lily (Hippeastrum puniceum)
32. Easter lily (Lilium longifolium)
33. Dutch hyacinth (Hyacinthus orientalis)
34. Persian violet, Sowbread (Cyclamen persicum)
35. Daylilies (Hemerocallis sp.)
36. African tulip tree (Spathodea campanulata)
37. Aloe vera (Aloe vera)
38. Giant alocasia (Alocasia macrorrhiza)
39. Plants of genus Colocasia
40. Dumbcane (Dieffenbachia sp)
41. Heart-leaved philodendron (Philodendron scandens, synonym: Philodendron discolor)
42. Tree philodendron (Philodendron selloum, synonym: Philodendron bipinnatifidum)
43. Elephant ear (Caladium sp.)
44. Flamingo lily (Anthurium andraeanum)
45. Golden pothos (Epipremnum aureum)
46. ZZ plant (Zamioculcas zamiifolia)
47. Arum lily, Calla lily (Zantedeschia aethiopica, Colocasia aethiopica)
48. Peace lily (Spathiphyllum wallisii)
49. Indian coral tree (Erythrina variegata)
50. Cockspur coral tree (Erythrina crysta-galli, syn. Corallodendron crista-galli)

 

Plants are toxic through a biochemical mechanism, whereas plants are injurious through a physical mechanism due to needle-shape calcium oxalate crystals.

Some common toxic and injurious plants are presented below.

In order to compile this article, the writer consults reliable websites and books so that a general and correct view is given on the toxicity and danger of the plants that are familiar to you.

Due to various reasons, the writer cannot provide all sources of information and pictures presented here. If thanks to this article on this non-profit website, someone can avoid poisoning and danger, then the writer could be tolerated.

1.     Oleander, Nerium (Nerium oleander, synonym: Nerium odorum)

This plant belongs to the Dogbane Family (Apocynaceae). It is at top of the article due to its extreme toxicity while it is planted widely, along roadsides, in parks and even in house yards.

Oleander plants are durable shrubs or trees that contain a gummy, clear sap. The leathery lance-shaped foliage is deep green and may be arranged opposite along the stems or in whorls. Oleander’s funnel-shaped flowers bloom in clusters at the twig tips from summer to fall, and come in shades of white, pink, red, or yellow. The flowers are often abundant, and some oleander varieties give off a pleasant fragrance. Oleanders typically grow to between 6-12 feet (1.8-3.6 m) feet tall, with a spread of the same width, but some may be trained to grow into small trees that reach up to 20 feet (6 m) tall.

Oleander plants contain several toxic elements, including cardiac glycosides, saponins, digitoxigenin, oleandrin, oleondroside, nerioside and other unknown toxins. These poisons are found in all parts of the oleander plant and are toxic whether the plant parts are dried or green. Ingestion of any part of the oleander plant can lead to serious illness and possibly death.

Ingesting oleander plant parts can result in a variety of symptoms ranging from moderate to severe or fatal. These include skin rash, blurred vision, visual disturbances such as halos, diarrhea, nausea, stomach pain, vomiting, loss of appetite, irregular or slowed heartbeat, weakness, low blood pressure, confusion, dizziness, headache, fainting, depression, drowsiness, or lethargy. Symptoms such as depression, loss of appetite, and halos in the vision are typically only present in cases of chronic or severe poisonings.

Humans have died after eating meat that was skewered with oleander stems. Ingesting a single leaf may be toxic to a person. The dry leaves remain toxic. Cattle, horses, and sheep have been poisoned experimentally. Children and family pets should be prevented from ingesting green or dry leaves, chewing stems, or sucking the nectar from flowers.

The Ministry of Health of Vietnam has issued a warning not to grow this plant in residential areas.

http://www.cbif.gc.ca/eng/species-bank/canadian-poisonous-plants-information-system/all-plants-scientific-name/nerium-oleander/?id=1370403266943
https://plants.ces.ncsu.edu/plants/all/nerium-oleander/
https://csuvth.colostate.edu/poisonous_plants/Plants/Details/143
http://homeguides.sfgate.com/nerium-oleander-plants-43989.html

2.     Poison hemlock (Conium maculatum, synonym: Cicuta maculata)

Pham Hoang Ho suspects that this plant, belonging to the Carrot or Parsley Family (Apiaceae), exists in Indochina. And if you live in North America and Europe you should be on guard because of three characteristics: (1) very high toxicity, (2) appearance similar to some edible plants, (3) high invasion near resettlements. The plant aggressively invades roadsides, construction sites, vacant lots, streambanks, and gardens, especially where the soil is moist. Due to its high invasion, the plant may grow around your house but you don’t know this.

Poison hemlock has interesting historic significance as the “hemlock tea” used for execution in ancient Greece, and the decoction used to put the philosopher Socrates to death.

All parts of poison hemlock can kill humans and animals, even when it is dried.

Foragers can easily mistake the poison hemlock with the wild carrot or Queen Anne’s lace (Dausuc carota), the water parsnip (Sium suave, Berula sp.), and others. Symptoms are variable and not characteristic: salivation, nausea, vomiting, thirst, vision disturbances, sweating, and vertigo. More severe symptoms may follow, such as hypertension and fast heart beat, followed by slow heart beat hypotension, and seizures. At a later stage, muscular weakness, paralysis and coma may ensue.

Toxicoses in livestock frequently occur and field reports of teratogenic effects in cattle and pigs have been reported. Poison hemlock contains at least five piperidine alkaloids, all of which are believed to contribute to the toxicity. Coniine and γ-coniceinepredominate and are believed also to contribute to the teratogenic effects. Cattle, pigs, goats, elk, wild geese and domestic turkeys have demonstrated a preference for Conium plant once they have acquired a taste for it.

European waterhemlock (Cicuta virose) which grows in Asia, Europe and North America, has similar habitat, appearance and toxicology.

https://en.wikipedia.org/wiki/Cicuta
https://www.cdc.gov/mmwr/preview/mmwrhtml/00026056.htm
https://www.invasiveplantatlas.org/subject.html?sub=5514
http://www.foodsafetynews.com/2015/05/10-people-treated-for-eating-poison-hemlock-in-washington/#.WxpIP54aa3A

3.     Yellow oleander; Be-still tree (Thevetia peruviana, synonym: Cascabela thevetia)

Thevetia peruviana which is in the Dogbane Family (Apocynaceae), is a small tree usually growing 3-8 m tall with a short trunk. The tree is grown widely, even in school yards  (as in the secondary school of this writer).

The plant is widely used in folk medicine in Central and South America, many of these uses having also spread to South-East Asia. In the Philippines and India the plant has become a household remedy for several ailments. It is sometimes cultivated for medicinal use and sold in local markets; it is also often grown as an ornamental and hedge, being valued for its floral display.

Its flowers are funnel-shaped, 3 inches (7.6 cm) long, and have 5 overlapping petals that open in a spiraled pinwheel. The flowers are followed by 1 1/2 inch (4 cm) in diameter, angled, semi-rhomboid, green ripening to brown or black fruits that usually contain two seeds. The leaves are glossy green above, pale green below, leathery, hairless, spirally arranged, and linear-lanceolate in shape. The broken foliage oozes toxic white latex sap.

All parts of the plant and especially the seeds are highly poisonous and contain toxic cardiac glycosides like thevetin and peruvoside that can cause severe illness or even death if ingested. The sap may cause skin irritation. Burning the wood or plant material can produce toxic smoke.

In a paper on treatment of Thevetia peruviana poisoning, M. Eddleston et al. describe 351 cases in Sri Lanka, in a three-year period, but say that there are ‘thousands’ of cases each year, the majority being deliberate ingestion by young women. Of the cases described in the paper only two died suggesting Thevetia is not the perfect suicide weapon it is sometimes said to be.

In general, it is said that under 10% of cases of ingestion will prove fatal.

One fatal incident was reported from Cyprus where a tourist, visiting from South-East Asia, was seen to pick and eat parts of the plant in a park, apparently in order to commit suicide.

Like many poison plants, its extremely bitter taste is a disincentive to accidental ingestion and it has a strongly emetic effect which further limits the harm it does.

The Ministry of Health of Vietnam has issued a warning not to grow this plant in residential areas.

http://www.thepoisongarden.co.uk/atoz/thevetia_peruviana.htm
https://wildlifeofhawaii.com/flowers/1516/thevetia-peruviana-be-still-tree/
http://tropical.theferns.info/viewtropical.php?id=Thevetia%20peruviana

4.     Yellow bell, Golden trumpet (Allamanda cathartica)

The tree, which belongs the Dogbane Family (Apocynaceae), is native to South and Central America. Their bright flowers have made it a popular ornamental plant. Its scent may be described as delicate and fruity. It has become naturalized throughout the tropics; it may be seen along roadsides, abandoned yards and dumps, even school yards.

Allamanda cathartica is notable for its medicinal properties although all parts of the plant contain allamandin, a toxic iridoid lactone. The leaves, roots and flowers are used as a laxative and emetic in traditional medicine in a number of tropical countries. Although the milky sap is known to contain antibacterial and possibly anticancer properties, it is poisonous and ingesting large amounts can be toxic. Effects of poisoning can also include rashes, itch, and blisters.

Don’t allow children to sip the nectar of the flowers, which is somewhat sweet. Initial numbness of lips and tongue indicates allergic reaction, although the toxic strengthe is milder compared with the two above-mentioned species in the same family.

The Ministry of Health of Vietnam has issued a warning not to grow this plant in residential areas.

http://thepoisondiaries.tumblr.com/post/40769127220/allamanda
http://naturalismavrotor.blogspot.com/2016/02/yellow-bell-study-article-in-progress.html

5.     Castor oil plant (Ricinus communis)

The castor oil plant, a woody herb belonging to the family of Spurge (Euphorbiacea), is a native of tropical Africa. The stalked leaves consist of usually eight radiating, pointed leaflets with slightly serrated edges and prominent central veins. Many varieties are green, but some are reddish brown. The flowers are green and inconspicuous, but pink or red in the pigmented varieties. Many stamens are near the base and branching pistils are near the top of the flower. The soft-spined fruits containing attractively mottled seeds are distinctive features of the plant.

It is grown as an ornamental in gardens, sometimes as a houseplant, and also grows as a weed. It is an annual in the south and a perennial in the tropics, and it may reach 15 feet (5 m) tall outdoors.

The seeds from the castor oil plant are extremely poisonous to people, animals and insects. One of the main toxic proteins is ricin, one of the most poisonous naturally occurring substances known. Poisoning by ingestion of the castor bean is due to ricin. Perhaps just one milligram of ricin can kill an adult. The symptoms are abdominal pain, vomiting, and diarrhea, sometimes bloody. Within several days there is severe dehydration, a decrease in urine, and a decrease in blood pressure. If death has not occurred in 3-5 days, the victim usually recovers.

If the seed is swallowed without chewing, and there is no damage to the seed coat, it will most likely pass harmlessly through the digestive tract. However, if it is chewed or broken and then swallowed, the ricin toxin will be absorbed by the intestines.

It is said that just one seed can kill a child. Children are more sensitive than adults to fluid loss due to vomiting and diarrhea, and can quickly become severely dehydrated and die.

Ricin was involved in one of Britain’s most famous unsolved murders which resembles the plot of a spy novel. On a September evening in London in 1978, Markov, a prize-winning Bulgarian author and BBC broadcaster who had been classified as a “non person” by the communist authorities, was waiting alongside commuters for a bus on Waterloo Bridge when he felt a stinging pain in his thigh. A heavily built stranger dropped an umbrella, mumbled “sorry” and fled in a taxi.

Markov thought little of the seemingly trivial incident and continued his journey home; he was dead of a high fever in three days. The James Bond-style murder weapon was an umbrella, partly developed by the Soviet KGB, which fired a pellet the size of a pinhead, containing the poison ricin.

The Ministry of Health of Vietnam has issued a warning not to grow this plant in residential areas.

https://poisonousplants.ansci.cornell.edu/toxicagents/ricin.html
https://www.telegraph.co.uk/news/2158765/Poison-tip-umbrella-assassination-of-Georgi-Markov-reinvestigated.html

6.     Angel’s trumpet, Anglels’ tears (Brugmansia suaveolens)

The genus Brugmansia has 7 species of small trees and shrubs in the nightshade family (Solanaceae), all are now listed as extinct in the wild by the IUCN Red List of Threatened Species. Angel’s trumpets are commonly grown as ornamentals in frost-free climates and in greenhouses, and several attractive hybrids have been developed. The plants are sometimes confused with the annual herbaceous plants of the related genus Datura. (Datura differs from Brugmansia in that they are herbaceous bushes, with erect rather than pendulous flowers –  and most have spines on their fruit).

All parts of the genus species are considered poisonous and contain the alkaloids atropine, scopolamine, and hyoscyamine. Ingestion of the plants can cause disturbing hallucinations, paralysis, tachycardia, and memory loss and can be fatal. Various species were used both ritualistically and as herbal medicine by indigenous peoples and their shamans, particularly in the northern Andes.

The Latin specific epithet suaveolens means “with a sweet fragrance”. Brugmansia suaveolens is grown widely, even along roadsides, in Da Lat, Vietnam, due to its beautiful flowers.

It is a semi-woody shrub or small tree, growing up to 3–5 m (10–16 ft) tall, often with a many-branched trunk. The leaves are oval, to 25 cm (10 in) long by 15 cm (6 in) wide, and even larger when grown in the shade. Its trumpet-shaped flowers are highly distinctive – they can be white, cream, yellow and pale orange or even pale pink in some varieties, and hang downward from fully pendulous up to nearly horizontal. The flowers are remarkably beautiful and sweetly fragrant, about 24–32 cm (9–13 in) long and shaped like trumpets. The corolla body is slightly recurved to 5 main points, but the very peaks in the true species are always curved outwards, never rolled back, and these peaks are short, only 1–2.5 cm (0.4–1.0 in) long.

Brugmansia suaveolens has been an essential aspect of South American ritual and medicine for many thousands of years. Children who misbehave badly may be given a small quantity of such a tea in order to teach them proper behavior. In much of Latin America, B. suaveolens leaves are applied externally to treat wounds, rashes, and ulcers. B. suaveolens contains tropane alkaloids, as do all species of Brugmansia. However, this particular species contains certain alkaloids that are unique to it, including cuscohygrine. The alkaloid content is highest when it is flowering.

Golden angel’s trumpet (Brugmansia aurea)

In South America, the most potent cultivar of Brugmansia aurea called “Culebra Borrachero” (meaning “drunken binge”) yields a drug called “devils’s breath”. According to the British Journal of Clinical Pharmacology, the drug – also known as hyoscine – causes the same level of memory loss as diazepam. There are countless stories of criminals using this drug to make a person to follow any instructions, like withdrawing own money at an ATM, or ransacking own house, etc. Such loss of control is due to the action of scopolamine on the central nervous system, making the victim act like a zombie. According to Dr Miriam Gutierrex, an expert in scopolamine at the Toxicology Department, the National University of Colombia, after the victims are exposed to scopolamine and do anything instructed by the criminals, they do not remember what happened so they do not report anything, because their memory is gone.

The U.S. Embassy in Bogota takes scopolamine very seriously and offers staff tips on how avoid being drugged. One piece of advice may seem obvious: Don’t let your drinks out of your sight when at a Bogota bar or nightclub. Still, American victims from time to time appear at the embassy seeking help, still shaking off a scopolamine hangover.

“I remember one case, an American reported being drugged,” an embassy official said. “He says to his doorman ‘Why did you let them walk out with my stuff.’ The doorman says, ‘Because you told me to.’“

https://en.wikipedia.org/wiki/Brugmansia_suaveolens
http://entheology.com/plants/brugmansia-suaveolens-aromatic-angels-trumpet/
http://entheology.com/plants/brugmansia-aurea-golden-angels-trumpet/
https://en.wikipedia.org/wiki/Brugmansia_aurea
https://www.britannica.com/plant/angels-trumpet https://www.biopsychiatry.com/scopolamine/borrachero.html
http://entheology.com/plants/brugmansia-aurea-golden-angels-trumpet/

7.     Devil’s trumpet (Datura metel, synonym: Datura alba)

The genus Datura of the Nightshade Family (Solanaceae) has 9 species, all are toxic, particularly their seeds and flowers, due to scopolamin. Poisoning symptoms are: hot, dry, and flushed skin, hallucinations, pupil dilation, headache, delirium, rapid and weak pulse, convulsions, and coma.

According to Dr-Prof Võ Văn Chi, there are three species of Datura in Việt Nam, all are described in this articles.

Datura species are herbaceous, leafy annuals and short-lived perennials which can reach up to 2 m in height. The leaves are alternate, 10-20 cm long and 5-18 cm broad, with a lobed or toothed margin. The flowers are erect or spreading (not pendulous like those of Brugmansia), trumpet-shaped, 5-20 cm long and 4-12 cm broad at the mouth; colors vary from white to yellow, pink, and pale purple. The fruit is a spiny capsule 4–10 cm long and 2–6 cm broad, splitting open when ripe to release numerous seeds. The seeds disperse freely over pastures, fields and even wasteland locations.

Datura metel is an annual or perennial herb growing up to 3 ft (0.91 m) high. It is slightly furry, with dark violet shoots and oval to broad oval leaves that are often dark violet as well. The pleasantly-scented 6-8 in (15-20 cm) flowers are immensely varied, and can be single or double, colors range from white to cream, yellow, red, and violet. The seed capsule is covered with numerous conical humps and a few spines. It is similar to D. innoxia, but D. metel has almost glabrous leaves and fruits that are knobby, not spiny. D. innoxia is pilose all over and has spiny fruits.

According to Thái Nguyễn Ngọc on web site “tieuluanduoclieu”, there are two cultivars:

• Datura metel forma alba: white flowers, green trunk and branches
• Datura metel forma violacea: purple spotted flowers, purple trunk and branches.

The Ministry of Health of Vietnam has issued a warning not to grow this plant in residential areas.

https://vi.wikipedia.org/wiki/C%C3%A0_%C4%91%E1%BB%99c_d%C6%B0%E1%BB%A3c
https://plants.ces.ncsu.edu/plants/all/datura-metel/

8.     Downy thorn apple (Datura innoxia, or Datura innoxia)

Datura innoxia is an annual to perennial herb to up to 1 m high with a spreading crown about 2 m in diameter. The stems of D. innoxia and its leaves are covered with short and soft greyish hairs that give the whole plant a greyish appearance.

Leaves are simple, elliptic, entire margins, with conspicuous pinnate venation alternately arranged along the stem. D. innoxia bears white tubular (trumpet) flowers that have green veins, 12-19 cm long, stigma well above anthers. Some people find the flowers fragrant at night, when the plant is blooming.

The fruit is an egg-shaped spiny capsule with numerous slender spines, about 5 cm in diameter. All spines nearly the same length (up to 1 cm long). The capsule stalk bends sharply downwards. Capsules produce brown seeds, 4-5 mm long. When ripe, the capsule splits open, dispersing the seeds.

Reproduction through spreading by seed and vegetative cuttings. The spiny capsule is also dispersed on the fur of animals.

Similar species

• Datura stramonium: erect capsules on straight stalks, black or grey seeds.
• Datura metel, Datura innoxia: capsules on a curved stalk, brown or yellow seeds.

Datura innoxia typically produces a complete inability to differentiate reality from fantasy (delirium, as contrasted to hallucination); hyperthermia; tachycardia; bizarre, and possibly violent behaviour; and severe mydriasis with resultant painful photophobia that can last several days. Pronounced amnesia is another commonly reported effect. There can easily be a 5:1 variation in toxins from plant to plant, and a given plant’s toxicity depends on its age, where it is growing, and local weather conditions. These wide variations make Datura exceptionally hazardous to use as a drug.

https://en.wikipedia.org/wiki/Datura_innoxia
https://keys.lucidcentral.org/keys/v3/eafrinet/weeds/key/weeds/Media/Html/Datura_inoxia_(Downy_Thorn_Apple).htm

9.     Jimson weed, Devil’s snare (Datura stramonium)

This plant is commonly observed in Vietnam, in bushes, vacant lands…

Datura stramonium is a foul-smelling, erect, annual, freely branching herb that forms a bush up to 60-150 cm (2-5 ft) tall. The root is long, thick, fibrous, and white. The stem is stout, erect, leafy, smooth, and pale yellow-green. The stem forks off repeatedly into branches, and each fork forms a leaf and a single, erect flower. The leaves are 8-20 cm (3-8 in) long, smooth, toothed, soft, and irregularly undulated. The upper surface of the leaves is a darker green, and the bottom is a light green. The leaves have a bitter and nauseating taste, which is imparted to extracts of the herb, and remains even after the leaves have been dried.

Datura stramonium generally flowers throughout the summer. The fragrant flowers are trumpet-shaped, white to creamy or violet, 6-9 cm (2 1⁄2–3 1⁄2 in) long, and grow on short stems from either the axils of the leaves or the places where the branches fork. The calyx is long and tubular, swollen at the bottom, and sharply angled, surmounted by five sharp teeth. The corolla, which is folded and only partially open, is white, funnel-shaped, and has prominent ribs. The flowers open at night, emitting a pleasant fragrance, and are fed upon by nocturnal moths.

The egg-shaped seed capsule is 3-8 cm (1-3 in) in diameter and either covered with spines or bald. At maturity, it splits into four chambers, each with dozens of small, black seeds.

A special characteristic is that the seed can be dormant deep in soil for several years, and when they are brought up they will germinate. Therefore, if you buy soil to enrich your garden, some day you will find Datura stramonium in your garden!

Datura has been used in traditional medicine to relieve asthma symptoms and as an analgesic during surgery or bonesetting. It is also a powerful hallucinogen and deliriant, which is used entheogenically for the intense visions it produces. However, the tropane alkaloids responsible for both the medicinal and hallucinogenic properties are fatally toxic in only slightly higher amounts than the medicinal dosage, and careless use often results in hospitalizations and deaths. Some people use the plant as a narcotic and die because they do not know when to stop!

Most cases of plant poisoning in Canada are due to Datura stramonium. Chidren see the flowers are attractive and suck honey from the nectars, and are poisoned. Cattle, goats, horses, chicken, sheep and pigs can be poisoned.

https://en.wikipedia.org/wiki/Datura_stramonium https://www.rhs.org.uk/advice/profile?PID=536 https://www.sciencedirect.com/science/article/pii/S2452247316600122
http://www.missouriplants.com/Bluealt/Datura_stramonium_page.html
http://www.cbif.gc.ca/eng/species-bank/canadian-poisonous-plants-information-system/all-plants-scientific-name/datura-stramonium/?id=1370403266829

10.  Night-blooming jasmine, Queen of the night (Cestrum nocturnum, synonym: Cestrum parqui)

This plant belongs to the Potato Family (Solanaceae), like the four above-mentioned. It is an evergreen woody shrub growing to 4 m (13 ft) tall. The leaves are simple, narrow lanceolate, 6-20 cm (2.4-7.9 in) long and 2-4.5 cm (0.79-1.77 in) broad, smooth and glossy, with an entire margin. The flowers are greenish-white, with a slender tubular corolla 2-2.5 cm (0.79-0.98 in) long with five acute lobes, 10–13 mm (0.39-0.51 in) diameter when open at night, and are produced in cymose inflorescences. A powerful, sweet perfume is released at night. The fruit is a berry 10 mm (0.39 in) long by 5 mm (0.20 in) diameter, either marfil white or the color of an aubergine. There is also a variety with yellowish flowers.

There are mixed reports regarding the toxicity of foliage and fruit. Like all Cestrum species, all parts of C. nocturnum are known to be highly toxic either fresh or when dried. C. nocturnum can be toxic to humans, and effects include hallucinations, nervous irritability, tachycardia, raised temperature, increased salivation, and paralysis. While a non-fatal poisoning of a child was reported, in the U.S. no poisonings have been reported since 2002 and there have been no records of any fatal poisonings. The plant is highly invasive, and as such, it forms a risk to livestock with approximately 60 leaves of Cestrum spp. material enough to result in the death of a 400 kg cattle beast.

http://www.iucngisd.org/gisd/species.php?sc=851
https://en.wikipedia.org/wiki/Cestrum_nocturnum http://entheology.com/plants/cestrum-nocturnum-night-blooming-jessamine/

11.  Sandbox tree (Hura crepitans, Hura brasiliensis)

This is an evergreen tree of the Spurge Family (Euphorbiaceae), native to tropical regions of North and South America, including the Amazon Rainforest. It is recognized by the many dark, pointed spines and smooth brown bark. These spines have caused it to be called “Monkey no-climb”.

Sandbox trees can grow very spreading, up to 60 m (200 ft) high, and the large ovate leaves grow to two feet (60 cm) wide. They are monoecious. The red flowers have no petals. Male flowers grow on long spikes; female flowers are solitary in axils. The fruit is a large capsule with explosive dehiscence; seeds can be launched at 70 m/s (160 mph). One source states that ripe capsules catapult their seeds as far as 100 m (330 ft). Another source states that seeds are thrown as far as 45 m (148 ft) from a tree, with a mode of about 30 m (98 ft). It has also been known as the “Dynamite tree”, so named for the explosive sound of the ripe fruit as it splits into segments.

Its fruits are pumpkin-shaped capsules, 1.4–2 inches (3–5 cm) long, 2–3.2 inches (5–8 cm) diameter, with 16 carpels arranged radially. Its seeds are flattened and about 0.8 inches (2 cm) diameter. In parts of Tanzania in Africa it has become invasive.

Picture: leaves, flowers, fresh and dried fruits.

The sandbox tree’s seeds taste good and that is bad. In Vietnam, some cases of non-fatal poisoning occurs as school children eat the seeds.

The latex is white like milk, or yellowish opaque, used in some area in South America to poison fish and to make poison arrows. These facts suggest precaution to all parts of the trees.

The sandbox tree is often planted along roadsides and particularly in schoolyards (as in the primary school of this writer), perhaps because of spines on the truck there is no risk of school children to climb up the tree.

According to Attenborough for BBC:

The hura tree protects its explosive fruits with a sap so toxic that it will raise great red welts if it touches human skin and even blind those who get it into their eyes. The macaws, however, are not put off. Long before the fruits are ripe, the birds rip them apart, pods, seeds and all, and then, after a meal that would have poisoned others, they fly to particular places on a river bank where they can gnaw out and swallow a special clay which detoxifies their meal.

https://en.wikipedia.org/wiki/Hura_crepitans
https://asknature.org/strategy/toxic-sap-protects-tree-seeds/#.WxtGH54aa3A

12.  Buddha belly, Gout plant  (Jatropha podagrica)

Jatropha podagrica, of the Spurge Family (Euphorbiaceae), is native to the tropical Americas but it is propagated as an ornamental plant in many parts of the world.

The plant is 30-100 cm high. Its stem is swollen into vasculum at the base and filled with thin sap. The plant bears bright red coral-like flowers throughout the year. The seed pods explode open when mature, and launch the seeds up to 15-20 feet (5-7 m) away.

Jatropha podagrica is also known for its incredible ability to attract a variety of butterflies wherever it is grown.

All parts, especially the fruits and seeds of the plant contain curcin, similar in toxic properties as ricin of the castor oil plant. Ingestion will cause vomiting and cardiovascular failure, leading to death if not treated timely.

The Ministry of Health of Vietnam has issued a warning not to grow this plant in residential areas.

https://florafaunaweb.nparks.gov.sg/special-pages/plant-detail.aspx?id=2154
http://www.llifle.com/Encyclopedia/SUCCULENTS/Family/Euphorbiaceae/22500/Jatropha_podagrica

13.  Purging nut tree, Physic nut (Jatropha curcas)

A member of the Spurge Family (Euphorbiaceae), this is a semi-evergreen shrub or small tree, reaching a height of 6 m (20 ft) or more. It is resistant to a high degree of aridity, allowing it to grow in deserts. It contains phorbol esters, which are considered toxic. However, edible (non-toxic) provenances native to Mexico also exist, known by the local population as piñón manso, xuta, chuta, aishte, among others. Jatropha curcas also contains compounds such as trypsin inhibitors, phytate, saponins and a type of lectin known as curcin.

Children eating the seeds develop symptoms of nausea, vomiting and diarrhea. Jatropha curcas is the most common cause of plant poisoning in Thailand during the period of 2001-2010.

24 cases of poisoning with Jatropha curcas seeds or fruits reported to poison centers in Paris and Marseille between December 2000 and June 2014.

https://en.wikipedia.org/wiki/Jatropha_curcas http://www.llifle.com/Encyclopedia/SUCCULENTS/Family/Euphorbiaceae/28980/Jatropha_curcas
https://www.ncbi.nlm.nih.gov/pubmed/26867365
https://www.ncbi.nlm.nih.gov/pubmed/25925815

14.  English ivy (Hedera helix)

This plant, belonging to the Ginseng Family (Araliaceae), is woody, evergreen, climbing or creeping vine; leaves alternate, simple, the juvenile form palmately 3-5-lobed, usually lacking hairs, often variegated; flowers small, greenish yellow, 5-parted; fruit fleshy, black.

This plant contains saponins, which have caused poisoning in cattle, dogs, sheep, and humans. Two chemicals in the sap can also cause severe contact dermatitis in sensitive humans. Cases of poisoning are found in older European literature; the plant grows naturally in Europe. Young children are often victim to this plant’s poison, most likely due to its curious demeanor. Ingestion can cause delirium, stupor, convulsions, hallucinations and fever, and contact with its leaves can cause skin irritation, itching, rash and blisters. Dermatitis is rare but can be severe. Weeping lesions and blisters respond slowly to treatment.

Cattle that ingested large quantities of the vines were ill for a few days. Humans who ingested the berries have shown symptoms, including coma.

http://www.cbif.gc.ca/eng/species-bank/canadian-poisonous-plants-information-system/all-plants-common-name/english-ivy/?id=1370403266849
https://listverse.com/2011/03/22/10-common-plants-you-didnt-know-were-toxic/

15.  Lily of the valley (Convallaria majalis)

A member of the Asparagus Family (Ruscaceae) is a herbaceous perennial plant that forms extensive colonies by spreading underground stems called rhizomes. New upright shoots are formed at the ends of stolons in summer, these upright dormant stems are often called pips. These grow in the spring into new leafy shoots that still remain connected to the other shoots underground, often forming extensive colonies. The stems grow to 15–30 cm tall, with one or two leaves 10–25 cm long; flowering stems have two leaves and a raceme of 5–15 flowers on the stem apex.

The flowers have six white tepals (rarely pink), fused at the base to form a bell-shape, 5–10 mm diameter, and sweetly scented; flowering is in late spring, in mild winters in the Northern Hemisphere it is in early March. The fruit is a small orange-red berry 5–7 mm diameter that contains a few large whitish to brownish colored seeds that dry to a clear translucent round bead 1–3 mm wide. Plants are self-sterile, and colonies consisting of a single clone do not set seed.

All parts of the plane are toxic, particularly the leaves. Water in which the cut flowers have been kept is also toxic. Though the water may yield enough toxin to be deadly, a “tea” made by boiling the leaves would certainly contain even more of the toxin and would be a more effective poison. Symptoms onset quickly and include nausea, vomiting, abdominal pain, flushing, hot flashes, dilated (enlarged) pupils, a red skin rash, excessive salivation, coma, and death. These glycosides can also cause deadly alterations in cardiac rhythm, which can lead to sudden collapse.

The toxin in the plant consists of three glycosides called convallarin, convallamarin, and convallotoxin; the third one has effects on the heart, causing slow and irregular heart beast that may lead to heart failure. Each plant contains a different amount of the toxin, so the leaves would vary greatly in their potency. In general, lily of the valley is not very toxic, because its glycosides are poorly absorbed in the digestive system.

http://www.thepoisongarden.co.uk/atoz/convallaria_majalis.htm
http://www.cbif.gc.ca/eng/species-bank/canadian-poisonous-plants-information-system/all-plants-scientific-name/convallaria-majalis/?id=1370403266819

16.  Pencil cactus (Euphorbia tirucali)

The genus Euphorbia has about 2,000 species with toxicity degrees from mild to moderately severe, in general not life-threatening.

Pencil cactus is not a true cactus but a member of the Spurge Family (Euphorbiacea). In nature, it grows as a 30-foot (10-m) tall, leafless tree with pencil-size green branches that function in photosynthesis. Tiny leaves appear at the ends of new branches when new growth occurs, but they quickly fall.

Among the species of the genus Euphorbia, pencil cactus is very toxic as its causes burns, and can cause blindness if it gets in the eyes. Euphorbon is a toxin in the sap. Plant owners who prunes pencil easily get the sap on their skin as it can spurt out strongly when a branch is cut. At first nothing happens to the victim who later may feel like hot fire on the skin even after some washing.

https://plants.ces.ncsu.edu/plants/all/euphorbia-tirucalli/
https://davesgarden.com/guides/articles/view/3133
https://en.wikipedia.org/wiki/Euphorbia

17.  African milk tree (Euphorbia trigona)

Euphorbia trigona is a perennial plant that has an upright stem and a number of branches that also grow upward. The stem and branches can have two or three sides. The stem itself is dark green with V-shaped light green patterns. Thorns about 5mm long are placed in pairs on the stem’s ridges. The drop shaped leaves grow from between the two thorns on each ridge. The plant has never been known to flower, and is possibly a hybrid.

As with many other Euphorbia species, the latex from the plant is poisonous and can cause skin irritations.

Picture: African milk tree (Euphorbia trigona), Crown of thorns (Euphorbia milii),
Indian spurge tree (Euphorbia neriifolia)

An article on Indian Journal of Opthalmology reports a case of a 60-year-old male who was trimming his garden hedge E. trigona plant and got sprayed with milky sap into his right eye. He had an immediate burning sensation and pain which was relieved partially by irrigation with water. After 16 hours, he had pain, burning with gross dimness of vision in the eye. After medical treatment, by 10 days all signs and symptoms had resolved.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2712704/

18.  Crown of thorns (Euphorbia milii)

It is suspected that the species was introduced to the Middle East in ancient times, and legend associates it with the crown of thorns worn by Christ.

It is a succulent climbing shrub growing to 1.8 m (6 ft) tall, with densely spiny stems. The straight, slender spines, up to 3 cm (1.2 in) long, help it scramble over other plants. The leaves are found mainly on new growth, and are obovate, up to 3.5 cm (1.4 in) long and 1.5 cm (0.59 in) broad. The flowers are small, subtended by a pair of conspicuous petal-like bracts, variably red, pink or white, up to 12 mm (0.47 in) broad.

The sap is moderately poisonous, and causes irritation on contact with skin or eyes. If ingested, it causes severe stomach pain, irritation of the throat and mouth, and vomiting. The poisonous ingredients have been identified as phorbol esters.

The toxicity of this species is similar to that of the African milk tree described above. An article on Indian Journal of Opthalmology reports a case of a 54-year-old woman who was pruning her Euphorbia milii houseplant when she felt a stinging sensation as a drop of sap entered her left eye. She did not wash her eyes immediately. Fifteen minutes later she felt severe pain, blepharospasm and dimness of vision in the left eye. By day 15 after medical treatment started, all signs and symptoms had resolve.

https://en.wikipedia.org/wiki/Euphorbia_milii https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2712704/

19.  Indian spurge tree (Euphorbia neriifolia)

Euphorbia neriifolia is glabrous erect branched succulent, xerophytic tree or shrub up to 20 ft or 1.8–4.5 m high with jointed cylindrical or obscurely 5-angled branches. The fresh young leaves are simple, dark green in color having leathery texture. The surface is glabrous with reticulate venation. The average leaf size is (8–14 ± 2) cm (length) and (4–8 ± 2) cm (breadth) and (1.3 ± 0.2) mm (thickness) with pointed and acute tip. The flowers are yellowish green in color. Fruits are looking like capsule.

The toxicity of this species is similar to that of the African milk tree described above. An article on Indian Journal of Opthalmology reports a case of a 51-year-old man was pruning his overgrown species of E. neriifolia in his garden when he felt some sap enter into his left eye. The eye became irritable and was immediately irrigated with tap water. After two weeks of treatment, all signs and symptoms were resolved and the patient regained full vision.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2712704/ https://davesgarden.com/guides/articles/view/3133

20.  Christmas plant (Euphorbia pulcherrima)

This is a shrub or small tree, typically reaching a height of 0.6–4 m (2–13 ft). The plant bears dark green dentate leaves that measure 7–16 cm (2.8–6.3 in) in length. The colored bracts – which are most often flaming red but can be orange, pale green, cream, pink, white, or marbled – are often mistaken for flower petals because of their groupings and colors, but are actually leaves. The colors of the bracts are created through photoperiodism, meaning that they require darkness (12 hours at a time for at least five days in a row) to change color. At the same time, the plants require abundant light during the day for the brightest color.

In the United States and perhaps elsewhere, there is a common misconception that the poinsettia is highly toxic. This misconception was spread by a 1919 urban legend of a two-year-old child dying after consuming a poinsettia leaf.

The Canadian Poisonous Plants Information System noted the death of a child in Hawaii who ingested a leaf of poinsettia but it was based on hearsay, and an old dog that ingested poinsettia reportedly experienced protracted vomiting, followed by renal failure, coma, and death. This is the only case in the literature of death to an animal. Case histories show that some humans develop a sensitivity to the latex, resulting in dermatitis. Short exposures to poinsettia in a few cases have led to bouts of vomiting, but no substantiated cases of death can be found in the literature.

While the sap and latex of many plants of the spurge genus are indeed toxic, the poinsettia’s toxicity is relatively mild. Its latex can cause an allergic reaction in sensitive individuals. It is also mildly irritating to the skin or stomach and may sometimes cause diarrhea and vomiting if eaten. Sap introduced into the human eye may cause temporary blindness.

An American Journal of Emergency Medicine study of 22,793 cases reported to the American Association of Poison Control Centers showed no fatalities, and furthermore that a strong majority of poinsettia exposures are accidental, involve children, and usually do not result in any type of medical treatment.

Poinsettia should no longer be regarded as a severely toxic plant.

http://www.cbif.gc.ca/eng/species-bank/canadian-poisonous-plants-information-system/all-plants-scientific-name/euphorbia-pulcherrima/?id=1370403266864
http://www.petpoisonhelpline.com/poison/poinsettia/
https://www.nature.com/scitable/blog/plantchemcast/the_dark_myth_of_the

21.  Lantana (Lantana camara)

Lantana camara is a small perennial shrub which can grow to around 2 m tall and form dense thickets in a variety of environments. Due to extensive selective breeding throughout the 17th and 18th Centuries for use as an ornamental plant there are now many different cultivars. Lantana camara has small tubular shaped flowers which each have four petals and are arranged in clusters in terminal areas stems. Flowers come in many different colors including red, yellow, white, pink and orange which differ depending on location in inflorescences, age, and maturity. After pollination occurs the color of the flowers change (typically from yellow to orangish, pinkish, or reddish), this is believed to be a signal to pollinators that the pre-change color contains a reward as well as being sexually viable, thus increasing pollination efficiency. The leaves are broadly ovate, opposite, and simple and have a strong odor when crushed. The fruit of L. camara is a berry-like drupe which turns from green to dark purple when mature. Both vegetative (asexual) and seed reproduction occur. Up to 12,000 fruits can be produced by each plant which are then eaten by birds and other animals which can spread the seeds over large distances, facilitating the spread of L. camara.

Picture: leaves, flowers and fruits, typical of wild lantana. Cultivars give flowers of different colors like purple and yellow, purple and white, or pink and yellow.

Lantana camara is known to be toxic to livestock such as cattle, sheep, horses, dogs and goats. The active substances causing toxicity in grazing animals is pentacyclic triterpenoids which result in liver damage and photosensitivity. Green unripe fruits of the plant are toxic to humans, whereas ripe fruits are edible as this writer knew in his childhood.

The California Poison Control System database for the period between 1997 and 2009 indicates 641 cases of kids who’d eaten the plant, most often its berries. There were no reports of severe effects, and fewer than one in 10 kids experienced mild symptoms such as vomiting and, less commonly, stomachache or diarrhea.

There was no clear difference in symptoms caused by eating the ripe or unripe berries or other parts of the plant. It is suggested that other poison control centers should change their guidelines to reflect this advice.

In Australia, lantana is considered as poisonous to stock. Most lantana poisoning occurs when stock unfamiliar with the plant are introduced to areas where lantana is found. Young animals are most at risk. Stock bred in lantana-infested country tend to avoid it unless forced to eat it through lack of adequate food. Significant lantana toxins are the triterpene acids, lantadene A (rehmannic acid), lantadene B, and their reduced forms.

Signs of lantana poisoning can appear after one feed and, in acute cases, within 24 hours. Poisoned animals may show signs of:

• excessive skin sensitivity to sunlight (photosensitization)
• liver damage, as shown by yellow discoloration (jaundice) of the whites of the eyes and gums, and skin of the nose and mouth
• reddening and inflammation of unpigmented (white) skin; muzzle may become inflamed, moist, ulcerated and very painful (pink nose) and slough (fall off)
• swelling of ears and eyelids if unpigmented
• reddening and discharge from the eyes (conjunctivitis)
• ulceration of the tip and under surface of the tongue (if unpigmented)
• blow fly and bacterial invasion of raw, exposed flesh, in chronic cases; affected skin may slough leaving raw ulcerated surfaces.

The animal may also:

• avoid sunlight (photophobia)
• stop eating
• appear sluggish, weak and depressed
• urinate frequently
• become constipated (most commonly) or have diarrhea with strong-smelling black fluid feces in severely affected animals
• become dehydrated.

https://en.wikipedia.org/wiki/Lantana_camara
https://www.reuters.com/article/us-lantana-toddlers/lantana-plant-safe-for-toddlers-idUSTRE6A02MI20101101
https://www.daf.qld.gov.au/__data/assets/pdf_file/…/IPA-Lantana-Poison-Flyer.pdf

22.  Crown flower, giant milkweed, swallow wort (Calotropis gigantea, synonym: Asclepias gigantea)

This species belongs to the Dogbane Family (Apocynaceae), and is a large shrub growing to 4 m (13 ft) tall. It has clusters of waxy flowers that are either white or lavender in color. Each flower consists of five pointed petals and a small “crown” rising from the center which holds the stamens. The plant has oval, light green leaves and milky stem. The latex of Calotropis gigantea contains cardiac glycosides, fatty acids, and calcium oxalate.

Picture: entire tree, branch with flowers, and fruit of Calotropis gigantea.

This species grows along sea shores, on sand dunes, roadsides, vacant land… where no other plant can compete. It produces copious amounts of thick milky sap which profusely exudes out on breaking the leaves or stalk of the plant

The plant latex is toxic due to gigantin, 15-20 times more potent than strychnine, causing symptoms of headache, dizziness, fever, skin rash…

In India, there are 2 cases of poisoning:

• In a routine exercise, troops accidentally went over Calotropis gigantea plants in fast moving vehicles during night mobilization leading to splashing of the milky sap all around. A series of 16 cases of ocular toxicity occurring within a span of 3 weeks are reported.
• A 27 year old patient reported with Calotropis plant milky sap drop entering into his left eye accidently. He developed an immediate burning sensation, redness of eyes and photophobia and diminution of vision. Two days after treatment, his visual acuity improved to 6/6 in two days.

The database of U.S. Food & Drug Administration (FDA) indicates that the plant is not toxic to dogs, but toxic to cattle and goats.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4297827/ https://www.accessdata.fda.gov/scripts/plantox/detail.cfm?id=22583

23.  Sodom apple (Calotropis procera)

Both species Calotropis gigantea and Calotropis procera closely resemble each other in appearance, and chemical and physiological actions.

This is medium-branched and perennial shrub or small tree that grow up to a height of 4–5 meters with milky latex throughout. It has white or pink flowers which are used to worship Lord Shiva during the festive season in the months of February and April every year in West Bengal.

The dried latex and dried root are used as an antidote for snake poisoning in Andhra Pradesh, India.

Picture: entire tree, branch with flowers, and fruit of Calotropis procera
(Source: Missouri Botanical Garden)

Calotropis procera is more toxic than Calotropis gigantea. Toxic symptoms are vomiting and diarrhea on ingestion. It exerts caustic effect to the skin on direct contact. It can lead to blindness if its latex is put in to the eyes, causing opacity to the cornea.

http://ijapr.in/index.php/ijapr/article/view/139 https://www.feedipedia.org/node/588 http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=276915&isprofile=0&

24.  Sago palm, King sago palm (Cycas revoluta)

This very symmetrical plant supports a crown of shiny, dark green leaves on a thick shaggy trunk that is typically about 20 cm (7.9 in) in diameter, sometimes wider. The trunk is very low to subterranean in young plants, but lengthens above ground with age. It can grow into very old specimens with 6–7 m (over 20 feet) of trunk; however, the plant is very slow-growing and requires about 50–100 years to achieve this height. Trunks can, but not often, branch several times, thus producing multiple heads of leaves.

The leaves are a deep semiglossy green and about 50–150 cm (20–59 in) long when the plants are of a reproductive age. They grow out into a feather-like rosette to 1 m (3.3 ft) in diameter. The crowded, stiff, narrow leaflets are 8–18 cm (3.1–7.1 in) long and have strongly recurved or revolute edges. The basal leaflets become more like spines. The petiole or stems of the sago cycad are 6–10 cm (2.4–3.9 in) long and have small protective barbs.

Cycad sago is extremely poisonous to humans and animals if ingested. Pets are at particular risk, since they seem to find the plant very palatable. Clinical symptoms of ingestion will develop within 12 hours, and may include vomiting, diarrhea, weakness, seizures, and liver failure or hepatotoxicity characterized by icterus, cirrhosis, and ascites. The pet may appear bruised, have nose bleeds, blood in the stool… The ASPCA Animal Poison Control Center estimates a fatality rate of 50 to 75% when ingestion of the sago palm is involved. Effects of ingestion can include permanent internal damage and death.

All parts of the plant are toxic; however, the seeds contain the highest level of the toxin cycasin. This toxin causes gastrointestinal irritation, and in high enough doses, leads to liver failure. Other toxins include beta-methylamino L-alanine, a neurotoxic amino acid, and an unidentified toxin which has been observed to cause hindlimb paralysis in cattle.

Cycads have been a source of food for many people who live in proximity to these plants. These plants must be carefully processed to remove toxins before they are edible.

https://en.wikipedia.org/wiki/Cycas_revoluta
http://plantnet.rbgsyd.nsw.gov.au/PlantNet/cycad/toxic.html

25.  Bird of pardise (Strelitzia reginae)

Strelitzia is a genus of about 5 or 6 species of monocot plants closely related to the bananas. The leaves of most Strelitzias are ‘paddle-shaped’ and resemble banana leaves except for longer petioles.

Strelitzia reginae is the most well-known species and its flower is the most bird-like. The plant grows to 2 m (6.6 ft) tall, with large, strong leaves 25–70 cm (9.8–27.6 in) long and 10–30 cm (3.9–11.8 in) broad, produced on petioles up to 1 m (39 in) long. The leaves are evergreen and arranged in two ranks, making a fan-shaped crown. The flowers stand above the foliage at the tips of long stalks. The hard, beak-like sheath from which the flower emerges is termed the spathe. This is placed perpendicular to the stem, which gives it the appearance of a bird’s head and beak; it makes a durable perch for holding the sunbirds which pollinate the flowers. The flowers, which emerge one at a time from the spathe, consist of three brilliant orange sepals and three purplish-blue or white petals. Two of the blue or white petals are joined together to form an arrow-like nectary. When the sunbirds sit to drink the nectar, the petals open to cover their feet in pollen.[

Leaves of genus Strelitzia are listed as ‘possibly toxic’ but few cases of actual toxicity exist in the literature, at least in small animal medicine. The seeds are supposedly more toxic and will cause vomiting if ingested.

http://homeguides.sfgate.com/bird-paradise-plants-dangerous-dogs-42142.html
https://davesgarden.com/guides/articles/view/1898

26.  Rhododendron, Azalea (Rhododendron sp.)

The genus Rhododendron, belonging to the Heath Family (Ericaceae) has 700-1.000 species, almost all have beautiful flowers, hybrid cultivars have more spectacular flowers. Horticulturists distinguish azalea as a group in the genus Rhododendron popular as house plants, and the group rhododendron is the remaining. They are distinguished as follows:

• azalea: 5 stamens, often bush or small trees
• rhododendron: 10 or more stamens, small to big trees.

One of the earliest accounts of mass poisoning dates back to the first century BCE when Roman troops were allegedly poisoned with honey by the Heptakometes of Turkey. The Roman soldiers were reported to be confused and vomiting and subsequently defeated in battle after eating the honey. We now believe that they were given honey made from the nectar of the flowering plant Rhododendron luteum.

Azaleas are very close relatives of rhododendrons and can cause the same type of toxicity. The toxic component of rhododendrons and azaleas can be found in very high concentrations in honey made by bees that feed on them. This usually occurs in dense populations of these plants, particularly in the Mediterranean region. In fact, the majority of more recent reports of poisoning from rhododendron and azaleas occurred in Turkey where people ingested the poisonous honey produced accidentally by small-scale beekeepers. There are also a few reports of toxicity in people who intentionally ate the honey because of a false belief that it could help with some ailments.

The poisonous honey is commonly referred to as “mad honey,” a nickname earned because of the confusion it is known to cause. The toxin can cause very low blood pressure and heart rate as well as irregular heart rhythm. These symptoms could be life threatening.

Ingestion of the “mad honey” is not the only way people have been poisoned by azaleas and rhododendrons. Eating the leaves, nectar, or flowers of the plants can also lead to toxicity. Although rare, serious and life-threatening toxicity has occurred when people intentionally ate the plant. Similar to myths surrounding “mad honey,” there are some areas of the world where the plant is believed to have medicinal properties.

Children may mistake the flowers for honeysuckle and suck on the nectar of the azalea flower. Generally, only mild symptoms such as mouth irritation, nausea, and vomiting are expected from such cases.

The bottom line: Serious poisoning is unlikely when small pieces of azalea or rhododendron are swallowed. But swallowing large amounts of any part of the plant or honey made from these flowering plants can cause life-threatening symptoms.

http://www.botanyvn.com/cnt.asp?param=news&newsid=998
http://rhodyman.net/rhodytox.html
https://modernfarmer.com/2014/09/strange-history-hallucinogenic-mad-honey/
https://www.zmescience.com/other/feature-post/mad-honey-deli-bal/
https://www.poison.org/articles/2015-mar/azaleas-and-rhododendrons
https://reliefweb.int/report/democratic-peoples-republic-korea/north-korea-today-no-154-jun-2008
https://plants.ces.ncsu.edu/plants/all/rhododendron-spp/
https://www.ncbi.nlm.nih.gov/pubmed/4057315
https://abcnews.go.com/Technology/JustOneThing/potentially-harmful-house-plants/story?id=8589505

27.  Bigleaf hydrangea (Hydrangea macrophylla)

The term macrophylla means large- or long-leaved. The opposite leaves can grow to 15 cm (6 in) in length. They are simple, membranous, orbicular to elliptic and acuminate. They are generally serrated. The inflorescence is a corymb, with all flowers placed in a plane or a hemisphere or even a whole sphere in cultivated forms. Two distinct types of flowers can be identified: central non-ornamental fertile flowers and peripheral ornamental flowers, usually described as “sterile”. All the flowers were fertile but the non-ornamental flowers were pentamers while the decorative flowers were tetramers. The four sepals of decorative flowers have colors ranging from pale pink to red fuchsia purple to blue. The non-decorative flowers have five small greenish sepals and five small petals. The fruit is a subglobose capsule.

Several parts of the plant — the buds, flowers and leaves — contain a compound known as glycoside amygdalin. It’s the amygdalin that has the potential to make hydrangea poisonous, because it can break down (in several different ways) to produce cyanide.

People and pets, including horses, dogs and cats, can experience hydrangea poisoning. For hydrangea poisoning to occur, a person or pet must eat very large quantities of the leaves, buds and/or flowers. There is one recorded case of a horse eating a potted hydrangea and becoming seriously poisoned. Typically hydrangea poisoning produces severe gastroenteritis symptoms, along with diarrhea, which is frequently bloody.

Some individuals harvest hydrangea flowers to dry and smoke for a cheap high. According to pharmacists, dried hydrangea flowers produce effects similar to symptoms produced by tetrahydrocannabinol (THC), which is found in cannabis plants. The reason hydrangea flowers produce a euphoric feeling is because the amygdalin compound breaks down to produce cyanide-type effects in the cells in the body. Effectively, the cyanide deprives cells of oxygen. Most often hydrangea smokers report effects of dizziness, heart rate increases and euphoria, but if they smoke enough, the results can include intestinal and respiratory distress.

Technically hydrangea is poisonous, but most experts agree that the amount of the plant that would have to be consumed would be very large — and thus quite unlikely. Nonetheless, keep an eye on pets and small children around hydrangeas. Their smaller bodies would be more likely to suffer bad side effects from consuming this plant..

https://www.diynetwork.com/how-to/outdoors/gardening/are-hydrangeas-poisonous
http://www.cbif.gc.ca/eng/species-bank/canadian-poisonous-plants-information-system/all-plants-scientific-name/hydrangea-macrophylla/?id=1370403266887

Flower bulbs resembling onions or shallots

Poisoning due to flower bulbs is often due to mistaking them for onions or shallots. Since the toxin in flower bulbs, lycorine, is thermal stable, poisoning occurs when flower bulbs are used in cooking due such mistake.

Picture: bulbs of the following plants (all herbaceous plants resembling onion):

• tulips (Tulipa sp.) in Lily Family (Liliaceae)
• lilies (Lilium sp.) in Lily Family (Liliaceae)
• daffodils (Narcissus sp.) in Amaryllis Family (Amaryllidaceae)
• belladonna (Amaryllis belladonna) in Amaryllis Family (Amaryllidaceae)
• Dutch hyacint (Hyacinthus orientalis) in Asparagus Family (Asparagaceae)
• Persian violet, Sowbread (Cyclamen persicum) in Primrose Family (Primulaceae)

Note: According to the Pacific Bulb Society, on the Internet there are mistakes over common and scientific names, leasing to mistakes over pictures, often due to resembling morphologies. The names and pictures presented here are from reliable sources.

The above-mentioned plants are presented next.

28.  Tulip – Tulip (Tulipa sp.)

Tulips form a genus Tulipa of spring-blooming perennial herbaceous bulbiferous geophytes (having bulbs as storage organs). The flowers are usually large, showy and brightly colored, generally red, yellow, orange, white, even black. They often have a different colored blotch at the base of the tepals (petals and sepals, collectively), internally.

Tulips rarely cause fatalities, but do contain toxic glycosides called tulipalin A and tulipalin B that may cause dizziness, abdominal pain and upset, and even, on occasion, convulsions. Leaves, stems, berries, and roots all contain toxic compounds. The most potent concentration is usually found in swollen underground stems, known variously as bulbs, rhizomes, and corms. In the past during times of food shortages, the bulbs have been consumed, mistaken for onions.

There are reports of skin irritation arising in persons handling large volumes of tulip bulbs, such as nursery workers.

Tulip is poisonous to cats, dogs and horses. During the Second World War, starving Dutch cattle – and sometimes starving Hollanders – ate tulip bulbs with sickening and occasionally fatal results. Sometimes curious people noted the bulb’s resemblance to an onion and used them as onion substitutes.

https://en.wikipedia.org/wiki/Tulip https://novascotia.ca/museum/poison/?section=species&id=124

29.  Daffodil (Narcissus sp.)

Narcissus is a genus of predominantly spring perennial plants of the amaryllis family (Amaryllidaceae). Various common names including daffodil, daffadowndilly, narcissus, and jonquil are used to describe all or some members of the genus. Narcissus has conspicuous flowers with six petal-like tepals surmounted by a cup- or trumpet-shaped corona. The flowers are generally white or yellow (also orange or pink in garden varieties), with either uniform or contrasting colored tepals and corona. Different cultivars give colors of corolla-tepal as orange-white, yellow-blue, white-white, pink-white, orange-yellow…

Daffodils rarely cause fatalities, but do contain toxic glycosides that may cause dizziness, abdominal pain and upset, and even, on occasion, convulsions.

The bubs can spread their toxicity to nearby plants such as rose, cabbage, paddy, making these plants slow growing.

The bottom line: All parts of the daffodil are toxic. When swallowed, it can cause nausea, vomiting, diarrhea, and abdominal pain. Eating the bulb can cause severe irritation of the mouth and stomach upset. These symptoms are usually not life threatening and resolve within a few hours.

https://laidbackgardener.blog/tag/narcissus-tazetta-chinensis/ https://novascotia.ca/museum/poison/?section=species&id=100# https://csuvth.colostate.edu/poisonous_plants/Plants/Details/121

30.  Belladonna lily (Amaryllis belladonna)

This is a perennial bulbous geophyte with one to two erect solid stems which appear in late summer. The inflorescence bears 2–12 showy fragrant funnel-shaped flowers on a ‘naked’ (leafless) stem, which gives it the other common name of naked-lady-lily. The pink flowers which may be up to 10 cm in length, appear in the autumn before the leaves (hysteranthy) which are narrow and strap shaped.

Picture: 3 cultivars of Amaryllis belladonna

There is confusion between the genera Amaryllis and Hippeastrum.

• Genus Amaryllis has two species, Amaryllis belladonna is much more common. At first, all species were in Amaryllis genus. In the 1980s, many species were grouped in the new genus Hippeastrum, leaving only 2 species in the existing genus. But by then, the plants had been marketed for decades under the common name as “amaryllis”, so the name has stuck. It’s very difficult to distinguish the two species, except that the Amaryllis bulb is always fully underground, and the plants have lots of leaves.
• Genus Hippeastrum has 90 species and over 600 cultivars. The bulbs always have their neck and part of the bulb above ground. Even now the name amaryllis is still commonly used to call Hippeastrum species.

According to the Canadian Poisonous Plants Information System, ingesting the bulbs has poisoned humans. The toxic alkaloid, lycorine, is the principal toxin, although small quantities of related alkaloids are also present.

https://www.pacificbulbsociety.org/pbswiki/index.php/Amaryllis https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/amaryllidaceae
http://www.cbif.gc.ca/eng/species-bank/canadian-poisonous-plants-information-system/all-plants-scientific-name/amaryllis-belladonna/?id=1370403266757 https://www.pacificbulbsociety.org/pbswiki/index.php/AmaryllisVsLycoris

31.  Barbados lily (Hippeastrum puniceum)

Also known as amaryllis lily, Barbados lily is neither a true lily nor a species of genus Amaryllis. Plants have 4–6 leaves, each of which is bright green, 30–60 cm long by 2.5–3 cm wide, strap-shaped (lorate) and tapers at the end to an acute apex. The leaves are not fully developed when the flowers appear. The flowers are borne in an umbel on a stem (scape) which is 40–60 cm tall. The umbel has lanceolate green bracts at its base. The petals, or more accurately tepals, are orange-red with paler bases. The lower two tepals are much narrower than the lateral ones.

The bulb is toxic due to lycorine and several other alkaloids.

The buls of many plants in the genus Hippeastrum contain lycorine that can cause vomit, diarrhea, convulsion if digested, and irritation on contact with the skin.

https://www.pacificbulbsociety.org/pbswiki/index.php/Hippeastrum https://plants.usda.gov/core/profile?symbol=HIPU

32.  Easter lily (Lilium longifolium)

The genus of true lily (Lilium) in the Lily Family (Liliaceae) has 75-110 species. These are true lilies, some of them quite toxic, only a few edible.

The Easter lily tends to grow to 50-100 cm tall. It has long oval leaves and the vein enters the horizontal direction. It produces pure white flowers on top of the stem. The stem has a cylindrical shape, with a diameter of about 5 cm.

Two other common lilies are:

• Madonna lily (Lilium candidum): unlike other lilies, it grows a basal rosette of leaves during winter, which die the following summer. A leafy floral stem, which generally grows 1.2 m tall, but exceptionally 2 m tall. The flowers are pure white and tinted yellow in their throats.
• Tiger lily (Lilium lancifolium synonym: Lilium tigrinum): all parts are toxic to cats, causing kidney failure.

Picture: Easter lily (Lilium longifolium), Madonna lily (Lilium candidum), Tiger lily (Lilium lancifolium synonym: Lilium tigrinum).

Lilium secies are mildy toxic to humans but highly toxic to cats. This is known to be so especially for L. longiflorum, though other Lilium and the unrelated Hemerocallis can also cause the same symptoms. The true mechanism of toxicity is undetermined, but it involves damage to the renal tubular epithelium (composing the substance of the kidney and secreting, collecting, and conducting urine), which can cause acute renal failure and liver failure. Cats are poison by eating any part of a lily, oy by licking pollen that may have brushed onto their coat. In experiments Lilium species are not toxic to dogs, horses, rats and rabbits.

You need only to be cautious with the bulbs.

Note: The Internet is rife with misstatements. The pollen-is-bad-for-humans warning could have risen out of the real threat it poses to cats. They lick lily pollen off their fur and often die from it. That warning could have morphed from fatal for cats to toxic for humans. There are similar examples with other plants.

http://vovworld.vn/en-US/in-pictures/madonna-lily-the-flower-of-april-230580.vov https://en.wikipedia.org/wiki/Lilium_longiflorum https://www.aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants/easter-lily http://thepoisondiaries.tumblr.com/post/46603462033/all-sections-of-the-easter-lily-lilium http://www.eattheweeds.com/tiger-lily/

33.  Dutch hyacinth (Hyacinthus orientalis)

Belonging to the Asparagus Family (Asparagaceae), this is a bulbous perennial herb; leaves basal and narrowly strap-shaped; flowers on an erect stalk, each 6-parted, funnel-shaped, variously colored: chalk white, blue, violet, yellow, red…, heavily fragrant.

The Dutch hyacinth is toxic due to lycorine. If the sap is on the skin, it causes irritation for some minutes. Bulb is the most toxic part, causing severe symptoms of cramp, indigestion, vomit, diarrhea if ingested a large quantity.

The bulb is also toxic to dogs, cats, horses, from mild symptoms like vomit and diarrhea to severe symptoms like bloody diarrhea and convulsion.

https://www.aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants/hyacinth
https://plants.ces.ncsu.edu/plants/all/hyacinthus-orientalis/

34.  Persian violet, Sowbread (Cyclamen persicum)

Belonging to the Primrose Family (Primulaceae), this plant has the toxin cyclamin in the tuberous rhizomes. The rhizome is bitter and found underground, so that children or family pets are unlikely to be exposed to the toxins. There is no information on the amounts of saponins, if any, in cyclamen foliage. The database of U.S. Food & Drug Administration – FDA contains no information on poisoning in humans.

When any part of the plant, especially the bulbs, are chewed or ingested by dogs and cats, it can result in clinical signs of drooling, vomiting and diarrhea. With large ingestions, these plants can result in cardiac problems (e.g., abnormal heart rate and rhythm), seizures and death.

https://www.accessdata.fda.gov/scripts/plantox/detail.cfm?id=25971 http://thepoisondiaries.tumblr.com/post/39388870002/winter-poisonous-plants-cyclamen-persicum http://www.cbif.gc.ca/eng/species-bank/canadian-poisonous-plants-information-system/all-plants-scientific-name/cyclamen-persicum/?id=1370403266820 http://www.petpoisonhelpline.com/poison/cyclamen/

35.  Daylilies (Hemerocallis sp.)

The genus Hemerocallis in the Grass tree Family (Xanthorrhoeaceae) contain a poison in the roots. Daylilies roots are said to be poisoned and killed some people in Asia.

On the other hand, some species are used in Chinese and Vietnamese medicines, such as (Picture, from left to right):

• Orange daylily (Hemerocallis fulva): flowers in orange color
• Late yellow daylily (Hemerocallis thunbergii): flowers in bright yellow color
• Citron daylily (Hemerocallis citrina) : flowers in citron-yellow color.

Flowers of some daylilies are edible cooked, not raw (because of a certain thermal unstable toxin?).

There are contradictory in the Western literature on the toxicity of daylilies, perhaps due to the confusion of “lily” and “daylily”, the former is often toxic. The American Society for the Prevention of Cruelty to Animals (ASPCA) advises that daylilies are toxic to cats and cattle, so some people infer that the plants are also toxic to human. The American Hemerocallis Society does not advise whether they are toxic, so precaution should be taken.

An American botanist, specialized in the genus Hemerocallis, advises not to eat daylilies due to possible sensitive reactions that look like poisoning symptoms. A biochemistry expert in the U.S. advises that only the species Hemerocallis fulva is edible and hybrid cultivars may be toxic.

The bottom line: do not try strange food. Take care of your health.

https://garden.org/thread/view/15995/Cats-and-Daylilies—survey-results/
https://delishably.com/vegetable-dishes/Should-You-Eat-Your-Daylilies

36.  African tulip tree (Spathodea campanulata)

Belonging to the Bignonia Family (Bignoniaceae), this is an evergreen tree that averages 30-50 feet (9-12 m) in height with a 25-30 foot (7-9 m) spread. It has an irregular, roundish, spreading crown with a fast growth rate. Leaves are evergreen, odd pinnately compound with 5-17 oval leaflets that are about 4 inches (10 cm) long with entire margins, opposite in arrangement, glossy, and dark green in color above and paler green below. New growth is bronzy. Newer stems are rusty brown. It has fairly prominent pinnate veins. The reddish-orange flowers are about 3-4 inches (7-10 xm) across, trumpet-shaped, scalloped or picoteed, and have four brown protruding stamens. The flowers are borne in terminal clusters. The velvety buds are horn to boat-shaped and filled with a liquid that squirts out when the bud is squeezed. It blooms periodically throughout the year with a heavier bloom in the spring in most areas.

Spathodea campanulata displays low toxicity, with reported adverse effects, serious allergic reactions. The nectar and pollen of its flowers are toxic to several types of insects including flies, ants and honey bees, thus honey made by affected bees could be toxic to consumers.

https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/spathodea
https://www.youtube.com/watch?v=QdBPJwvre0Y
https://www.embrapa.br/busca-de-publicacoes/-/publicacao/1005962/the-effect-of-toxic-nectar-and-pollen-from-spathodea-campanulata-on-the-worker-survival-of-melipona-fasciculata-smith-and-melipona-seminigra-friese-two-amazonian-stingless-bees-hymenoptera-apidae-meliponini

37.  Aloe vera (Aloe vera)

Belonging to the Asphodel Family (Asphodelaceae), Aloe vera is a stemless or very short-stemmed plant growing to 60–100 cm (24–39 in) tall, spreading by offsets. The leaves are thick and fleshy, green to grey-green, with some varieties showing white flecks on their upper and lower stem surfaces. The margin of the leaf is serrated and has small white teeth. The flowers are produced in summer on a spike up to 90 cm (35 in) tall, each flower being pendulous, with a yellow tubular corolla 2–3 cm (0.8–1.2 in) long. Like other Aloe species, Aloe vera forms arbuscular mycorrhiza, a symbiosis that allows the plant better access to mineral nutrients in soil.

Aloe vera leaves contain phytochemicals under study for possible bioactivity, such as acetylated mannans, polymannans, anthraquinone C-glycosides, anthrones, other anthraquinones, such as emodin and various lectins.

It is also common practice for cosmetic companies to add sap or other derivatives from aloe vera to products such as makeup, tissues, moisturizers, soaps, sunscreens, incense, shaving cream and shampoos. It is not widely known, however, that it is, in fact, poisonous. The white gel, which is not poisonous, inside the leaves, is covered in a thin yellow layer of aloin and anthraquinone c-glycoside, which are very toxic. If eaten in large enough quantities, it is known to cause abdominal cramping, nausea and vomiting, diarrhea and red urine, though not due to blood. Breaking a piece off to sooth irritated skin is generally considered safe, with the exception of those sensitive to latex.

Ingestion of Aloe preparations is associated with diarrhea, hypokalemia, pseudomelanosis coli, kidney failure, as well as phototoxicity and hypersensitive reactions. Recently, Aloe vera whole leaf extract showed clear evidence of carcinogenic activity in rats, and was classified by the International Agency for Research on Cancer as a possible human carcinogen.

For eating raw, the green and yellow layers must be discarded, only the transparent gel part is safe to eat

The plant is also toxic to cats and dogs.

38.  Giant alocasia (Alocasia macrorrhiza)

Injury due to calcium oxalate

Species in the Arum Family (Araceae) is injurious in physical mechanism of calcium oxalate (not a poison), not in biochemical mechanism of poisons as presented above.

The whole family is known to have irritant properties on the buccal mucous membrane when the fresh plants are eaten or even just chewed. The irritant properties are due to calcium oxalate needle-shape crystals. They are formed and located in special cells called ideoblasts.

Picture: 3 different types of idioblast under the microscope.

The needle-shape calcium oxalate crystals are packaged in bundles called raphides which are submerged in a gelatinous substance within a thick-walled cell (idioblast). When the plant is chewed, sap of the plant or saliva causes the gelatinous mass to swell. The calcium oxalate crystals are expelled strongly under pressure. This is like thousands of needles stabbing into the mucous membrane of the mouth, tongue and lips and embed themselves in the oral cavity. The symptoms are local irritation like burning by fire and excessive salivation in people, and even laryngospasm (uncontrolled muscular contraction of the vocal cords). In rare cases, a tracheostomy can be lifesaving. Salivation, gagging, colic and bloody diarrhea are known to occur in animals, but death is rare.

In case the plant contains a toxin, calcium oxalate crystals cause more problems because by wounding the lining of the mouth and digestive tract, they enable the toxin to enter the body through the damaged area. This toxin might otherwise pass through the body and either be unabsorbed or be broken down into less harmful substances in the digestive tract.

Among the species of genus Alocasia, only the giant alocasia (Alocasia macrorrhiza) can be found in the of toxic plant database of the U.S. Federal Drug Aministration – FDA. It can cause injury not as severe as by the genus Dieffenbachia but its victim numbers, perhaps because there are more mistakes with edible plants of similar morphology.

According to the Centre for Health Protection of Hong Kong, a total of 35 outbreaks of calcium oxalate food poisoning were recorded from January 2008 to April 2011, involving 49 affected persons. Watercress, Chinese kale, lettuce, spinach and Chinese boxthorn were the vegetables identified to be associated with the calcium oxalate food poisoning this year. As these vegetables are unlikely to contain high level of calcium oxalate raphides (needle-shaped crystals), it was suspected that the vegetables might have been mixed with small amount of calcium oxalate raphides-containing plants accidentally. The elephant ears plant is known to contain calcium oxalate.

According to the affected persons of suspected calcium oxalate food poisoning cases, their commonly reported symptoms matched the ones described in literatures, which included numbness and burning sensation of the tongue, mouth and lips, swelling of tongue or lips. Furthermore, some patients reported gastrointestinal symptoms, such as nausea, abdominal pain and diarrhea as well.

To prevent calcium oxalate food poisoning, Hong Kong authorities advise not to use the leaves of giant alocasia plant to cover vegetables.

In Vietnam, poisoning occurs due to the mistake for the edible Alocasia odora, often used in Vietnamese food.

Due to similar morphologies of the Alocasia plants, do not eat any part of the plant that you are not sure to be edible.

https://www.sciencedirect.com/topics/veterinary-science-and-veterinary-medicine/calcium-oxalate
http://www.cfs.gov.hk/english/multimedia/multimedia_pub/multimedia_pub_fsf_58_03.html
https://www.accessdata.fda.gov/scripts/plantox/detail.cfm?id=4640
http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=276573&isprofile=0&
https://floridata.com/Plants/Araceae/Alocasia%20macrorrhiza/947

39.  Plants of genus Colocasia

Alocasia and Colocasia are both plants of the Arum Family (Araceae). They have very large leaves, and the name elephant’s ears is used for both genera.

Genus Colocasia of the Arum Family (Araceae) has about 35 species or more. Colocasia esculenta is grown for its tubers and leave stalks, and also grows in the wild. This is one of the first plants domesticated by humans, with different cultivars giving different types of tubers.

The two genera Alocasia and Colocasia can be distinguished as follows:

• Alocasia: the stiff leaf stems, or petioles, extend into the leaves. This causes the leaves to follow the line of the petioles. As a result, most Alocasia leaves tend to point upwards. Alocasia plants grow best in shade; full sun exposure can damage these plants. They need soil that drains well and doesn’t stay soggy.
• Colocasia: the petioles connect down from the notches in the leaves. This enables the leaves to droop or hang at a downward angle. Colocasia plants grow best with full sun exposure. They thrive in wet soil and can be grown in standing water..

Even so, the species are crossed to form cultivars with different morphologies, and it’s difficult to determine the original species.

Injuries can be caused through a physical mechanism due to needle-shape calcium oxalate crystals, as explained above for the giant taro.

In addition, asparagine may cause vomit and mental disturbance if a large amount of the plant is ingested.

Colocasia plants also cause injury to cats, dogs and horses.

https://plants.ces.ncsu.edu/plants/all/colocasia-esculenta/
https://www.dovemed.com/healthy-living/first-aid/first-aid-colocasia-plant-poisoning/
https://www.childrens.health.qld.gov.au/poisonous-plant-taro-colocasia/

40.  Dumbcane (Dieffenbachia sp)

The stems of the plants are thick and fleshy with elliptical, or oval or oblong-shaped variegated foliage. The leaves are usually large and gradually tapering towards the apex. They are green in color with deep green border, and white or yellow spots and bands along the lateral vein. The leaves are glossy and they can grow up to a length of 15-40 cm.

The plant got the name ‘dumb cane’, because of its poisonous sap, which if ingested can cause pain and swelling of the tongue, and the victim cannot speak. Injuries can be caused through a physical mechanism due to needle-shape calcium oxalate crystals, as explained above for the giant taro.

If the leaves are chewed or if their sap is ingested, it can cause a burning sensation and inflammation of the mouth, throat, tongue, and the lips. The sap can also cause diarrhea and vomiting, if it is ingested. If it comes in contact with the skin, one can experience itching, redness, and dermatitis. The plant is also toxic for the pets.

The Internet spreads the news that the plant can kill a child in less than a minute and an adult in 15 minutes, or the victim will be blind if the plant sap get into the eye. Experts agree that the plant is indeed injurious but is not life-threatening, and will not make an eye blind.

The website Indian Pediatrics reports that among 188 cases of toxic plant ingestions identified by Mrvos et al., the dieffenbachias accounted for 32.5% of the case. Majority of the involved children were aged 4-12 months. Only 2.1% (4 case) of the patients were severely symptomatic.

https://gardenerdy.com/dieffenbachia-plant https://thegardeningcook.com/dieffenbachia-poisoning/
http://omargardens.com/blog/2016/04/the-dieffenbachia-plant-wont-kill-you-in-15-minutes-here-is-why/
https://www.indianpediatrics.net/mar2012/mar-247-248.htm

41.   Heart-leaved philodendron (Philodendron scandens, synonym: Philodendron discolor)

Philodendron is a big genus of the Arum Family (Araceae), with about 500-700 species (depending on authors). Heart-leaved philodendron is a popular house plant because it is extremely easy to grow. It’s also known as the sweetheart plant.

Heart-shaped, glossy leaves emerge bronze, then quickly turn green. The leaves are typically 2-4 in (5-10 cm) long, and cover its long, slender stems that can grow to 4 ft (1.2 m) or more. One interesting fact is that the leaf morphology changes according to the plant age.

Injuries can be caused through a physical mechanism due to needle-shape calcium oxalate crystals, as explained above for the giant taro.

A recent review in Canada of the Canadian Poisonous Plants Information System indicate that two-thirds of 188 plant poisoning cases were due to the plants of genus Philodendron. Only one person had symptoms which were mild. But another source indicated that an 11 month old child chewed the leaves of a philodendron plant (Araceae) and developed oropharyngeal erosions and dysphagia. Esophageal erosions of the mid third of the esophagus and on esophageal stricture at the level of the cricoid were diagnosed 16 days post-ingestion. Unexpected sudden death on day 17 was attributed to vagotonia secondary to the esophageal lesions caused by philodendron leaves.

http://www.cbif.gc.ca/eng/species-bank/canadian-poisonous-plants-information-system/all-plants-scientific-name/philodendron-scandens/?id=1370403266963
https://www.ncbi.nlm.nih.gov/pubmed/2398518

42.  Tree philodendron (Philodendron selloum, synonym: Philodendron bipinnatifidum)

Philodendrons are injurious to humans and pets. Injuries can be caused through a physical mechanism due to needle-shape calcium oxalate crystals, as explained above for the giant taro.

Picture: tree philodendron: LEFT: young plant, RIGHT: mature plant

Chewing the leaves of philodendrons results in painful burning and swelling of the mouth parts because of the oxalates. Family pets can also exhibit signs of toxicity if they chew on leaves of philodendrons.

https://plants.ces.ncsu.edu/plants/all/philodendron-selloum/ https://abcnews.go.com/Technology/JustOneThing/potentially-harmful-house-plants/story?id=8589505

43.  Elephant ear (Caladium sp.)

Caladium is a genus of flowering plants in the family Araceae. The common name elephant ear is also used for the closely related genera Alocasia, Colocasia, and Xanthosoma). There are over 1000 named cultivars of from the wild species such as Caladium bicolor, Caladium hortulanum, Caladium picturatum…

The wild plants grow to 15–35 inches (40–90 cm) tall, with leaves mostly 6-18 inches (15–45 cm) long and broad.

Injuries can be caused through a physical mechanism due to needle-shape calcium oxalate crystals, as explained above for the giant taro.

The plant is injurious to horses, cats and dogs. Symptoms are oral irritation, pain and swelling of mouth, tongue and lips, excessive drooling, vomiting (not horses), difficulty swallowing.

https://www.aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants/caladium
http://www.pawsdogdaycare.com/toxic-and-non-toxic-plants/caladium-hortulanum-poisonous-pets

44.  Flamingo lily (Anthurium andraeanum)

This plant, in the Arum family (Araceae), is an ornamental plant with large, fleshy leaves and bright red or pink spathe flowers. The flowers consist of a red to pink bract or sheath called a spathe, which opens out flat and often shows puckering of the veins. The spathe is broad ovate to heart shaped, 10-15cm long. The central spike or spadix is white or yellow, 8-12 cm long. The leaves are ovate or heart-shaped, 17-50cm long and 11-22cm wide. The sap is clear.

All parts of the plant contain the toxin hydrangine, also called umbelliferon, as well as calcium oxalate. Injuries can be caused through a physical mechanism due to needle-shape calcium oxalate crystals, as explained above for the giant taro.

Chewing any part can result in painful burning of the lips, mouth, tongue and throat. Sometimes acute inflammatory reactions including blistering and swelling of tissues can occur.

Other plants in the genus Anthurium should also considered to be injurious.

https://www.childrens.health.qld.gov.au/poisonous-plant-flamingo-flower-anthurium-andraeanum/
http://www.globinmed.com/index.php?option=com_content&view=article&id=102622:anthurium-andraeanum&catid=135&Itemid=141
http://www.cbif.gc.ca/eng/species-bank/canadian-poisonous-plants-information-system/all-plants-scientific-name/anthurium-andraeanum/?id=1370403266765
https://en.wikipedia.org/wiki/Anthurium_andraeanum

45.  Golden pothos (Epipremnum aureum)

This plant, in the Arum Family (Araceae), is an evergreen vine with stems green and striped with white or yellow; leaves heart-shaped, variegated; flowers in a spadix surrounded by a spathe. One interesting feature of this plant is that, if grown indoor the leaves are uniformly small, but if grown in soil outdoor the leaves are gradually bigger with time.

Picture: Golden pothos – LEFT: grown indoor; RIGHT: ground in garden outdoor

All parts of the plant contain calcium oxalate. Injuries can be caused through a physical mechanism due to needle-shape calcium oxalate crystals, as explained above for the giant taro.

However, the injury is not severed. Skin irritation is minor or lasting only for a few minutes. The plant is also injurious to cats and dogs.

https://www.childrens.health.qld.gov.au/poisonous-plant-pothos-epipremnum/ https://plants.ces.ncsu.edu/plants/all/epipremnum-aureum/

46.  ZZ plant (Zamioculcas zamiifolia)

ZZ plant, in the Arum Family (Araceae), is an ornamental rhizomatous perennial plant, 45-60 cm tall, with leathery, glossy dark green leaves up to 60cm long, succulent and pinnate. Each leave has 6-8 pairs of leaflets 7-15 cm long, elliptic-ovate and broadest above the middle. Flowers consist of a central spike, 5-7 cm long, yellow to brown/bronze in color, crowded with numerous tiny florets and surrounded by a bract or spathe. The flowers are on shorter stems usually partially hidden amongst the base of the plant.

Picture: entire plant, tubers and flower of ZZ plant.

Injuries can be caused through a physical mechanism due to needle-shape calcium oxalate crystals, as explained above for the giant taro.

A plant expert has dismissed recent social media claims that a popular house plant causes cancer as lacking scientific proof. Dean of the Faculty of Agriculture at Universiti Putra Malaysia (UPM) Prof Ghizan Saleh said that no scientific research had been carried out to establish a connection between the plant and cancer. “There is no scientific data that says the plant can cause cancer,” he said. The Uiversiti Sains Malaysia (USM) asked social media users to stop sharing unverified news about the university.

http://legendsrumors.blogspot.com/2015/12/houseplant-zanzibar-gem-causes-cancer.html https://www.edgeprop.my/content/no-proof-house-plant-causes-cancer-says-expert https://www.childrens.health.qld.gov.au/poisonous-plant-zanzibar-gem-zamioculcas-zamiifolia/

47.  Arum lily, Calla lily (Zantedeschia aethiopica, Colocasia aethiopica)

All parts of the arum lily in the Arum Family (Araceae) should be considered toxic, although the leaves of some species may contain little or no toxin. Injuries can be caused through a physical mechanism due to needle-shape calcium oxalate crystals, as explained above for the giant taro. The plant is also toxic due to proteinase.

Symptoms are intense burning sensation of the mouth, throat, lips and tongue; excessive drooling, choking and swelling of the throat, inability or difficulty swallowing (dysphagia). These symptoms may continue to occur up to two weeks after ingestion. Ingestion of larger quantities can result in severe digestive upset; extreme difficulty breathing, rapid shallow gasps (dyspnea). If massive amounts are consumed the symptoms become much more severe and can include any or all of the above with the addition of convulsions, renal failure, coma and death. It is possible to recover from severe calcium oxalate poisoning, however, in most cases permanent liver, and kidney damage may have already occurred.

http://www.pawsdogdaycare.com/toxic-and-non-toxic-plants/arum-lily

48.  Peace lily (Spathiphyllum wallisii)

Spathiphyllum in  is a genus of about 40 species of monocotyledonous flowering plants native to tropical regions of the Americas and southeastern Asia.

The peace lily is not a true lily in the Lily Family (Liliaceae), but in the Arum Family (Araceae). It is a herbaceous perennial which produces flowers in the typical aroid structure: a densely crowded inflorescence called a spadix is subtended by one large bract called a spathe (occasionally two spathes are produced, with the upper spathe smaller). The spadix is generally cream or ivory when young, and turns green with age; the spathe is generally white or white with green nerves distally from the margin, turning green with age. Leaves are basal, glossy and somewhat deeply veined, ovate and acuminate. The petioles are long and the leaves arch gracefully. The plant produces offsets at the base and in time becomes a dense clump.

All parts of the plant: stem, leaves, flowers, even pollens, contain calcium oxalate, injurious in the mechanism as explained for the elephant ear plant.

Picture: the entire, plant, flower in spathe, and fruit of the peace lily.

https://en.wikipedia.org/wiki/Araceae https://www.gardeningknowhow.com/houseplants/peace-lily/is-peace-lily-toxic-to-dogs.htm

49.  Indian coral tree (Erythrina variegata)

The genus Erythrina, in the Bean Family (Fabaceae), has some 110 species and belongs to .

The seeds of all members of this genus are said to be poisonous.

Erythrina variegata has nearly 30 synonyms. This indicates that there are variations in morphology such that there are different classifications.

Erythrina variegata is a thorny deciduous, picturesque, broad and spreading tree growing to 18-24 m tall and spread 6-12 m. It has many stout branches that are armed with black tiger’s claw spines. There are curved spines (really more like prickles) on the long leaf stalks too. The leaves are pinnate with a 20 cm (7.9 in) petiole and three diamond shaped leaflets, each leaflet about 6 in (15 cm). It has dense clusters of scarlet or crimson flowers and black seeds. The leaves are used to wrap fermented meat (“nem”) in Vietnam. Before the leaves come out in late winter or early spring, coral tree puts on a spectacular show with bright crimson flowers 2-3 in (5-7 cm) long in dense terminal clusters. It may flower a little during the summer, too. The beanlike pods that follow the flowers are cylindrical, about 15 in (38 cm) long, and constricted between the reddish brown seeds. The naturally occurring variety ‘orientalis’ has the veins of its leaflets highlighted with yellow or pale green.

The leaves and seeds contain low concentrations of alkaloids and have narcotic properties. The seeds contain the alkaloids hypaphorine, erysodine, and erysopine; the leaves and bark contain the poison erythrinine, which act upon the nervous system.

Saponins are present in the leaves, bark and seeds. Although poisonous, they are poorly absorbed by the human body and so most pass through without harm. Saponins are much more toxic to some creatures, such as fish, and hunting tribes have traditionally put large quantities of them in streams, lakes etc. in order to stupefy or kill the fish.

https://en.wikipedia.org/wiki/Erythrina_variegata http://tropical.theferns.info/viewtropical.php?id=Erythrina+variegata

50.  Cockspur coral tree (Erythrina crysta-galli, syn. Corallodendron crista-galli)

There are about 10 synonyms of this species.

Erythrina crista-galli, in the Bean Family (Fabaceae), is a small tree, the girth of its trunk measuring 50 cm (20 in). Normally it grows 5–8 m (16–26 ft) tall.

The root is a taproot with nodules produced by nitrogen-fixing bacteria. The bacteria live in symbiosis with the tree, facilitating the tree’s absorption of nitrogen in return for organic substances which the bacteria need. The tree’s trunk is woody with irregular, spiny branches. These branches form a layer without definite form and die after flowering.

The plant contains alkaloids that have powerful narcotic and purgative effects.

This species is one of the most toxic in the genus Erythrina. In Mexico, the seeds are use as rat poison, leaves and bark as fish poison.

https://vi.wikipedia.org/wiki/V%C3%B4ng_m%E1%BB%93ng_g%C3%A0
https://www.accessdata.fda.gov/scripts/plantox/detail.cfm?id=9299

General references

Phạm Hoàng Hộ (1999). Cây cỏ Việt Nam / Illustrated Flora of Vietnam, Quyển I, II và III. Nhà Xuất bản Trẻ Tp HCM C.P. Khare (ed.) (2007. Indian Medicinal Plants – An Illustrated Dictionary. Springer, New Delhi. Nelsom L.S; R.D. Shih; M.J. Balick (2007). Handbook of Poisonous and Injurious Plants, Second Edition. The New York Botatinal Garden & Springer. http://misc.medscape.com/pi/iphone/medscapeapp/html/A817016-business.html https://dengarden.com/gardening/Dangerous-Beauties-Twenty-Toxic-Houseplants-to-Avoid-Around-Children-and-Pets

First aids

To deal with toxic or injuries caused by plants, immediate action is vital (15 first minutes is critical).

• If the skin has rash, or swelling, itching, remove any clothing that has touched the plant or rash, then gently wash the affected area of skin thoroughly with soap (or dishwashing soap or detergent) and cool water to remove any poisonous residue. Be sure the water used to clean the area does not spread poison by running over other parts of your body. If there is no water, use clinic alcohol.
• Scrub under nails with a brush.
• Apply wet compresses or ice to the skin to reduce itching and blistering. Follow the directions on any creams and lotions. Do not apply to broken skin, such as open blisters.
• Calamine lotion can also be used, except on the face or on the genitals.
• If the eyes are irritated by plant sap, splash clean water in the eyes for at least 10 minutes.
• An antihistamine such as diphenhydramine (Benadryl) can be taken to help relieve itching. Follow directions on the package. Drowsiness may occur.
• If you are under the shower, be careful how the water drains off the area you are washing. You could easily wash the sap residue from one place to another place downstream on your body. You definitely don’t want to damage your extra sensitive body parts.
• Do not scratch. Wear gloves for the child, or wrap the hand when the child sleep to prevent scratching.
• If any eye is affected by plant sap, wash it under running water for 10-15 minutes. Bottled drinking water is best, tap water is second best.
• Wash the affected mouth many time with water.

For animals

• Rapid treatment with activated charcoal
• Induced vomiting can reduce the amount of toxin absorbed.

Bring the victim to a health care facility to check.

If ingesting any part of the plant:

• Do not cause vomit as this may be harmful.
• Bring the patient to a health care facility even when the symptoms are not severe, in case the situation may get worse, also to have inspection. Of course it’s up to you to weigh the cost vs. the benefits.
• If a plant containing calcium oxalate is ingested, give the victim yogurt, or milk or cheese to precipitate thee calcium oxalate crystals.
• In case of severe poisoning of extremely toxic plant (like the first ten plants in this article) and it takes time to go to a health care facility and the victim is still conscious, give activate carbon to adsorb the toxin. If the victim is in coma, do not give anything to the mouth.
• When evacuating the victim to the health care facility, bring along parts of the plant.

For cats and dogs, force the affected animal to drink 3% hydro peroxide to incite vomiting. Bring to a veterinarian if necessary.

Prevention

The better measure is prevention, because there is no specific antidote for the toxin; health care personnel provides symptomatic treatment only

• Before buying a plant, have the store label it with the common name and, if known, scientific name.
• Identify and label the plants in your area, yard, and home.
• Show grandparents and baby sitters where the plant label is. It is very hard for poison specialists to identify plants from a description given on the phone. Know the names of your plants before a poisoning happens.
• Place toxic or injurious plants out of sight and out of reach of children, and of cats.
• Teach children not to put any part of a plant in the mouth, and even not to touch the plant just in case the plant part is broken and the plant sap adheres on the child’s skin.
• Keep plants, seeds, fruits and bulbs stored out of reach of children.
• Also keep them from cats and dogs. It’s a big trouble when you pets have diarrhea in your house!
• Store labeled bulbs and seeds safely away from children, pets, and food-storage areas. Avoid confusing bulbs with edible onions.
• Equip the first-aid box with the materials and medicine indicated above..
• Wear gloves and protective eyeglasses while gardening. For very toxic plants, wear trousers and long-sleeved shirt.
• Discard plant leaves and flowers in a safe way so that children and pets cannot get to them.
• Do not burn any part of the plant. Smoke from fires made of twigs and other parts of poisonous plants, including poison oak, can irritate or harm the eyes, throat, and other parts of the body.

http://ucanr.edu/sites/poisonous_safe_plants/Preventing_Poisoning_Exposures_471/
https://www.cdc.gov/niosh/topics/plants/symptoms.html
https://www.poisoncontrol.org/prevention/poisonous-plants/

Conclusion

In theory, it is a simple matter to identify toxins in the plants. In practice, it is the amount eaten (the dose) that decides how poisonous a substance is. Different individual plants can contain different amounts of their toxins, including having none at certain times or when grown in certain locations or under certain conditions. The result is that a number of toxic plants are used in traditional medicine.

Some plants are more toxic than others. The good news is that most are to be consumed in large quantities to cause any real damage. Often the bitter taste repels a child or pet, and stops them from ingesting much of the plant.

Have no fear of growing decorative houseplants in your home; most are safe.

An important point is: Be cautious with plants that have white latex. The oleander and yellow oleander are in this category.

Be aware of misleading information on the Internet. Due to the confusing names, a plant of mild toxicity may be labeled as dangerous!

Information is provided to you so that you can remain calm instead of panic, and know how to prevent poisoning. The most vulnerable are toddlers under 3 years old, and cats – keep an eye on them while you are pruning your plants.

Updated on: 14-Jun-2018 – Compiled by: Diệp Minh Tâm

Note: this article is still open. It will be supplemented when new information is available.