Poisonous Plants: Heartbreak Grass

An Asian vine known to be deadly poisonous has been in the news lately. Alexander Perepilichny, a Russian banker turned whistleblower who provided information on tax fraud committed by the Russian state and the Russian Mafia, mysteriously died while jogging back in November 2012. Last year, a botanist at Royal Botanic Gardens, Kew was called in to help with the ongoing investigation. Analyses revealed traces of a compound found in Gelsemium elegans, suggesting that Perepilichny had been poisoned and calling into question the orignal claim that there was no foul play in his death.

Gelsemium is a genus in the family Gelsemiaceae. It is composed of three species, two of which are native to North America (G. rankinii and G. sempervirens). Gelsemium elegans is native to China and Southeast Asia. All species are poisonous due to a number of alkaloids found in virtually all parts of the plant and particularly concentrated in the roots and leaves. The most toxic and abundant compound is gelsemine, an alkaloid related to strychnine.

Gelsemium elegans, commonly known as heartbreak grass, is a twining vine with oppositely arranged, narrowly ovate leaves and yellow to orange flowers with five petals that are fused near the base. It occurs in thickets and scrubby forests. According to news reports (NPR and ABC News), it has a history of being used in assassinations by Chinese and Russian contract killers. Finding traces of it in Perepilichny’s body understandably raises questions about his death. The investigation continues, and the Kew botanist is now a “star witness.” 

Gelsemium elegans (image credit: Flora of China)

Gelsemium elegans (image credit: Flora of China)

Poisoning by heartbreak grass is not a pleasant experience. Its affects can be felt soon after ingestion and, depending on the amount ingested and the time that lapses between ingestion and treatment, death – usually by asphyxiation – can be imminent. The Hong Kong Journal of Emergency Medicine reported on two cases of Gelsemium elegans poisoning, in which a husband and wife consumed the plant after mistaking it for the medicinal herb, Mussaenda pubescens. The 65 year old woman became dizzy, weak, and nauseous thirty minutes after consuming the plant. Then she went unconscious. Quick medical attention saved her life. She was released from the hospital eight days later, after spending time in intensive care and undergoing various treatments. Her 69 year old husband experienced similar dizziness and weakness, but promptly vomited and called for an ambulance.

The report states that “ingestion of G. elegans is highly poisonous regarding its neurological and respiratory depressive effects,” and that “early and active respiratory support is the key to successful resuscitation.” The report also wisely warns: “People should best avoid eating any wild plants because of the similar external appearance of certain poisonous and non-poisonous species.” Proper and skilled identification is paramount, especially where plants are growing so closely together that they intertwine, “leading to inadvertent ingestion.”

All Gelsemium species have been used medicinally to treat a variety of ailments. If used properly, they may provide effective treatments; however, in their book, The North American Guide to Common Poisonous Plants and Mushrooms, Nancy Turner and Patrick von Aderkas state – regarding the medicinal use of G. sempervirens – that the “plant [is] considered very dangerous for herbal use.” They also list the plant as a skin and eye irritant and claim that the flower’s nectar produces poisonous honey.

gelsemium sempervirens 1

Gelsemium sempervirens

Commonly known as Carolina jasmine and yellow jessamine, G. sempervirens is a woodland plant found in west Texas and throughout the southeastern United States. It is an attractive, evergreen, perennial vine with yellow, fragrant, funnel-shaped flowers and is grown as an ornamental in its native region and beyond. Most poisonings occur when the stems and leaves are consumed, usually as some kind of “herbal preparation;” however, the Handbook of Poisonous and Injurious Plants claims that “there are cases of children who were poisoned after sucking on the flowers.” Headaches, dizziness, blurred visions, dry mouth, and difficulty speaking and talking are a few of the initial symptoms experienced after ingesting this plant. When cases are severe, muscles in the body experience weakness, spasms, and contractions. Symptoms, in other words, are akin to strychnine poisoning, and barring prompt and proper medical care, results can be similarly deadly.

More Poisonous Plants Posts:

Poisonous Plants: Lima Beans

I don’t recall being a picky eater as a child, but one food I could barely stomach was lima beans. The smell, the texture, the taste, even the look of them, really didn’t sit well with me. I know I’m not alone in this sentiment. Lima beans are a popular thing to hate, and I have avoided them ever since I was old enough to decide what was allowed on my plate. To be fair, the only lima beans I remember trying were the ones included in the familiar bag of frozen mixed vegetables, which might explain why I didn’t like them. But little did I know there is another reason to avoid them – lima beans are poisonous.

That’s a strong statement. In case you’ve eaten lima beans recently or are about to, I should ease your concerns by telling you that you have little to worry about. Commonly cultivated lima beans are perfectly safe to eat as long as they are cooked properly, and even if they are eaten raw in small doses, they are not likely to hurt you. But again, why are you eating lima beans? They’re gross.

lima beans in cans

Phaseolus lunatus – commonly known as lima bean as well as a number of other common names – is in the legume family (Fabaceae) and is native to tropical America. It is a perennial, twining vine that reaches up to 5 meters. It has trifoliate leaves that are alternately arranged, and its flowers are typically white, pink, or purple and similar in appearance to pea flowers and other flowers in the legume family. The fruits are hairy, flat, 5 – 10 cm long, and often in the shape of a half moon. The seeds are usually smooth and flat, but are highly variable in color, appearing in white, off-white, olive, brown, red, black, and mottled.

P. lunatus experienced at least two major domestication events – one in the Andes around 4ooo years ago and the other in Central America more than 1000 years ago. Studies have found that the first event yielded large seeded varieties, and the second event produced medium to small seeded varieties. Wild types of P. lunatus have been given the variety name sylvester, and cultivated types are known as variety lunatus; however, these don’t appear to be accepted names by plant taxonomists and perhaps are just a way of distinguishing cultivated plants from plants growing in the wild, especially in places where P. lunatus has become naturalized such as Madagascar.

Distinguishing wild types from cultivated types is important though, because wild types are potentially more poisonous. Lima bean, like several other plants we eat, contains compounds in its tissues that produce cyanide. These cyanide producing compounds are called cyanogenic glucosides and are present in many species of plants as a form of defense against herbivores. The predominant cyanogenic glucoside in lima beans is called linamarin, which is also present in cassava and flax.

Fruits of lima bean (Phaseolus lunatus) - photo credit: wikimedia commons

Fruits of lima bean (Phaseolus lunatus) – photo credit: wikimedia commons

In order for lima beans to poison you, they must be chewed. Chewing brings linamarin and the enzymes that react with it together. Both compounds are present in the cells of lima beans, but they reside in different areas. Once they are brought together, a reaction ensues and hydrogen cyanide is produced. Because cyanide isn’t produced until after the plant is consumed, the symptoms of cyanide poisoning can take a little while to occur – often several hours.

Cyanide poisoning is not a pretty thing. First comes sweating, abdominal pain, vomiting, and lethargy. If the poisoning is severe, coma, convulsions, and cardiovascular collapse can occur. There are treatments for cyanide poisoning, but if treatment comes too late or if the dose is large enough, death results.

Cassava (Manihot esculenta) is particularly well known for its history of cyanide poisonings. It is a staple crop of people living in tropical areas of Africa and South America. Humans can readily metabolize small amounts of cyanide, and processes like crushing and rinsing, cooking, boiling, blanching, and fermenting render cassava safe to eat. However, consuming cassava that isn’t prepared properly on a consistent basis can result in chronic illnesses, such as konzo, which is a major concern among cultures in which cassava is an important food source.

I guess I should reiterate at this point that most cultivated lima beans contain low (read “safe”) levels of cyanogenic glucosides and, particularly when cooked, are perfectly safe to eat. I’m still not totally convinced that I should eat them though. While researching this article I came across numerous sites claiming that lima beans are delicious while offering various recipes to prove it. I even came across this story in which a self-proclaimed “lima bean loather” was converted to the side of the lima bean lovers. I don’t fancy myself much of a cook, so I’m hesitant to attempt a lima bean laden recipe for fear that it will only make me hate them more. If anyone out there thinks they can convince me otherwise with their tasty creation, be my guest.

And now a haiku:

You are lima beans
I despised you as a child
Perhaps unfairly?

Follow these links to learn more about cyanide producing crops and lima beans:

2015: Year in Review

Raise your glass. 2015 has come to a close, and Awkward Botany is turning three. Two great reasons to celebrate.

I started the year with the goal of posting at least once per week. Consider that goal accomplished, with a couple of bonus posts thrown in for good measure. I had also deemed 2015 the “Year of Pollination.” The underlying purpose was to teach myself more about pollinators and pollination while also sharing my interest in pollination biology with the wider world. That endeavor yielded 17 posts. There is still so much to learn, but we are making some headway. I started two new series of posts (Poisonous Plants and Botany in Popular Culture) and I continued with two others (Ethnobotany and Drought Tolerant Plants). I also went on a couple of field trips and wrote a few book reviews. All of that is reflected below in “Table of Contents” fashion.

Year of Pollination:

Botany in Popular Culture

Poisonous Plants

Ethnobotany

Drought Tolerant Plants

Book Reviews

Field Trips

Three posts that perhaps didn’t get the attention they deserve:

juniper in the snow

Going forward, I will continue to post regularly – as there is no shortage of plant-related things to write about – but I will likely take a week off here and there. I have other projects in mind – some related to Awkward Botany, some not – that will certainly demand much of my attention and time. I have some big ideas for Awkward Botany and beyond, and I will share those with the wide world in due time. For now, I would just like to say thanks all for reading, for commenting, and for sharing Awkward Botany with your friends. Overall, it has been a great year here at Awkward Botany headquarters, and I have you to thank for that. I feel privileged to be part of a community that is infatuated with plants and is fascinated by the natural world.

Good riddance to 2015. It was good, but it gets better. Now we look ahead to 2016. May it be filled with peace, love, and botany.

Poisonous Plants: Castor Bean

A series of posts about poisonous plants should not get too far along without discussing what may be the most poisonous plant in the world – one involved in high and low profile murders and attempted murders, used in suicides and attempted suicides, a cause of numerous accidental deaths and near deaths, developed for use in biological warfare by a number of countries (including the United States), and used in bioterrorism attacks (both historically and presently). Certainly, a plant with a reputation like that is under tight control, right? Not so. Rather, it is widely cultivated and distributed far beyond its native range – grown intentionally and used in the production of a plethora of products. In fact, products derived from this plant may be sitting on a shelf in your house right now.

Ricinus communis, known commonly as castor bean or castor oil plant, is a perennial shrub or small tree in the spurge family (Euphorbiaceae) and the only species in its genus. It is native to eastern Africa and parts of western Asia but has since been spread throughout the world. It has naturalized in tropical and subtropical areas such as Hawaii, southern California, Texas, Florida, and the Atlantic Coast. It is not cold hardy, but is commonly grown as an ornamental annual in cold climates. It is also grown agriculturally in many countries, with India, China, and Mozambique among the top producers.

Silver maple leaf nestled in the center of a castor bean leaf.

Silver maple leaf nestled in the center of a castor bean leaf.

Castor bean has large palmately lobed leaves with margins that are sharply toothed. Leaves are deep green (sometimes tinged with reds or purples) with a red or purple petiole and can reach up to 80 centimeters (more than 30 inches) across. Castor bean can reach a height of 4 meters (more than 12 feet) in a year; in areas where it is a perennial, it can get much taller. Flowers appear in clusters on a large, terminal spike, with male flowers at the bottom and female flowers at the top. All flowers are without petals. Male flowers are yellow-green with cream-colored or yellow stamens. Female flowers have dark red styles and stigmas. The flowers are primarily wind pollinated and occasionally insect pollinated. The fruits are round, spiky capsules that start out green often with a red-purple tinge and mature to a brown color, at which point they dehisce and eject three seeds each. The seeds are large, glossy, bean-like, and black, brown, white, or often a mottled mixture. They have the appearance of an engorged tick. There is a small bump called a caruncle at one end of the seed that attracts ants, recruiting them to aid in seed dispersal.

Female flowers and fruits forming on castor bean.

Female flowers and fruits forming on castor bean.

All parts of the plant are toxic, but the highest concentration of toxic compounds is found in the seeds. The main toxin is ricin, a carbohydrate-binding protein that inhibits protein synthesis. The seeds need to be chewed or crushed in order to release the toxin, so swallowing a seed whole is not likely to result in poisoning. However, if seeds are chewed and consumed, 1-3 of them can kill a child and 2-6 of them can kill an adult. It takes several hours (perhaps several days) before symptoms begin to occur. Symptoms include nausea, vomiting, severe stomach pain, diarrhea, headaches, dizziness, thirst, impaired vision, lethargy, and convulsions, among other things. Symptoms can go on for several days, with death due to kidney failure (or multisystem organ failure) occurring as few as 3 and as many as 12 days later. Death isn’t imminent though, and many people recover after a few days. Taking activated charcoal can help if the ingestion is recent. In any case, consult a doctor or the Poison Control Center for information about treatments.

The seeds of castor bean are occasionally used to make jewelry. This is not recommended. In The North American Guide to Common Poisonous Plants and Mushrooms, the authors warn that “drilling holes in the seeds makes them much more deadly because it exposes the toxin.” Wearing such jewelry can result in skin irritation and worse. The authors go on to say that “more than one parent has allowed their baby to suck on a necklace of castor beans.” I doubt such parents were pleased with the outcome.

castor bean seeds

Castor beans are grown agriculturally for the oil that can be extracted from their seeds. Due to the way its processed, castor oil does not contain ricin. The leftover meal can be fed to animals after it has been detoxified. Castor oil has been used for thousands of years, dating as far back as 5000 BC when Egyptians were using it as a fuel for lamps and a body ointment, among other things. Over the centuries it has had many uses – medicinal, industrial, and otherwise. It makes an excellent lubricant, is used in cosmetics and in the production of biofuel, and has even been used to make ink for typewriters. One of its more popular and conventional uses is as a laxative, and in her book, Wicked Plants, Amy Stewart describes how this trait has been used as a form of torture: “In the 1920’s, Mussolini’s thugs used to round up dissidents and pour castor oil down their throats, inflicting a nasty case of diarrhea on them.”

A couple of years ago, I grew a small stand of castor beans outside my front door. I was impressed by their rapid growth and gigantic leaves. I also enjoyed watching the fruits form. By the end of the summer, they were easily taller than me (> 6 feet). I collected all of the seeds and still have them today. I knew they were poisonous at the time, but after doing the research for this post, I’m a little wary. With a great collection of castor bean seeds comes great responsibility.

The castor beans that once grew outside my front door.

The castor beans that once grew outside my front door.

There is quite a bit of information out there about castor beans and ricin. If you are interested in exploring this topic further, I recommend this free PubMed article, this Wikipedia page about incidents involving ricin, this article in Nature, and this entry in the Global Invasive Species Database. Also check out Chapter 11 (“Death by Umbrella”) in Thor Hanson’s book, The Triumph of Seeds.

Poisonous Plants: Baneberry

For all the benefits that plants offer humanity – the distillation being that Earth would be uninhabitable without them – there is still reason to be wary of them. In a world lousy with herbivores, plant species that are unpalatable have a greater chance of survival. Inflicting serious injury or death upon being ingested – or even by coming in contact with an unsuspecting visitor – offers even greater assurance that a plant will survive long enough to reproduce, passing along to its progeny any traits that led to its superior fitness. The traits in this case are chemical compounds that can be toxic when delivered at the right dose to the right organism. This is the nature of poisonous plants, and the reason why from a young age we were all likely warned not to eat every tasty looking berry we come across and not to go tromping carelessly through an area where certain plants might be present. Plants aren’t out to get us per se, but some do have the potential to cause us great harm. Informing ourselves and taking precautions is advised.

This is the first in a series of posts about poisonous plants. The list of poisonous plants is long, so it’s going to take a while to get through them all. There are some plants that are not generally considered poisonous but can cause illness or death to those who are allergic to them – like peanuts. I don’t plan to include such plants, but there may be some exceptions along the way. The popular author Amy Stewart wrote a book about poisonous and other nefarious plants entitled, Wicked Plants: The Weed that Killed Lincoln’s Mother and other Botanical Atrocities. Below is an excerpt from her introduction to that book that I thought would be worth including here:

Do not experiment with unfamiliar plants or take a plant’s power lightly. Wear gloves in the garden; think twice before swallowing a berry on the trail or throwing a root into a stew pot. If you have small children, teach them not to put plants in their mouths. If you have pets, remove the temptation of poisonous plants from their environment. The nursery industry is woefully lax about identifying poisonous plants; let your garden center know that you’d like to see sensible, accurate labeling of plants that could harm you. Use reliable sources to identify poisonous, medicinal, and edible plants. (A great deal of misinformation circulates on the Internet, with tragic consequences.)

Baneberry (Actaea spp.)

“Bane” is defined as deadly poison or a person or thing that causes death, destruction, misery, distress, or ruin. The word seems fitting as a common name to describe a plant with a berry that when ingested is said to have an almost immediate sedative effect on the heart and can ultimately lead to cardiac arrest. Baneberry is a name given to several plants in the genus Actaea, two of which are the main focus of this post – red baneberry (Actaea rubra) and white baneberry (Actaea pachypoda).

Actaea is in the family Ranunculaceae – the buttercup family – a family that consists of several common ornamental plants including those in the genera Ranunculus, Delphinium, and Clematis. A. rubra and A. pachypoda are commonly found in the understory of wooded areas in North America – A. rubra is the most widespread of the two species, occurring throughout North America except Mexico and the southeastern U.S. states; A. pachypoda occurs in eastern Canada and most eastern and Midwestern U.S. states.

The flowers of red baneberry, Actaea rubra (photo credit: wikimedia commons)

The flowers of red baneberry, Actaea rubra (photo credit: wikimedia commons)

Red baneberry is an herbaceous perennial that emerges in the spring from a basal stem structure called a caudex or from a rhizome, dying back to the ground again in the fall. One or several branching stems reach from 1 to 3 feet high, each with compound leaves consisting of 2-3 leaflets. The leaflets are deeply lobed and coarsely toothed. Several small, white flowers appear in spring to early summer clustered together in an inflorescence called a raceme. The petals are inconspicuous, but the stamens are large and showy. The flowers are said to have a rose-like scent. A variety of insects pollinate the flowers, after which green berries form, turning red or occasionally white by mid to late summer.

The berries of red baneberry, Actaea rubra (photo credit: www.eol.org)

The berries of red baneberry, Actaea rubra (photo credit: www.eol.org)

Red baneberry occurs on diverse soil types and in diverse ecosystems across its expansive native range. It seems to prefer, moist, shady, nutrient rich, acidic sites, and is considered an indicator of such places. It can be found in deciduous, coniferous, and mixed forested areas. Its preference for moist sites means that it can also be found in swamps, along stream banks, and in other riparian areas.

White baneberry has a relatively smaller native range and is found in very similar environments. It also has many of the same features and habits as red baneberry, with the main distinction being its striking white berries formed on prominent, stout, bright red axes and peduncles (the “stems” and “branches” of the racemes). The stigmas are persistent on the berries, forming large black dots on each berry and giving it another common name, doll’s eyes. This is a feature of red baneberry as well, but is much more striking on the white berries.

Baneberry is occasionally browsed by livestock and wildlife including deer, elk, and small mammals. However, it has a low degree of palatability and isn’t very nutritious. Birds, unaffected by their poisonous qualities, eat the berries and are the main seed dispersers of baneberry.

The berries of white baneberry or doll's eyes Actaea pachypoda (photo credit: www.eol.org)

The berries of white baneberry or doll’s eyes, Actaea pachypoda (photo credit: www.eol.org)

The roots and berries are the most poisonous parts of baneberry, however all parts are toxic. The berries are quite bitter, so it is not likely that one would eat enough of them to receive a severe reaction. If ingested, symptoms include stomach cramps, dizziness, vomiting, diarrhea, delirium, and circulatory failure. Eating six or more berries can result in respiratory distress and cardiac arrest. The toxin in the plant has yet to be clearly identified. Protoanemonin is present, as it is in all plants in the buttercup family, but the real toxicity of the plant is probably due to an essential oil or a poisonous glycoside. There have been no reported deaths due to the consumption of red or white baneberry, but a European species of baneberry (A. spicata) has been linked to the death of several children.

Native Americans were aware of baneberry’s toxicity, so rather than use it as a food source, they used it medicinally. Among other things, the root was used as a treatment for menstrual cramps, postpartum pain, and issues related to menopause, and the berry was used to induce vomiting and diarrhea and as a treatment for snakebites. Leaves were chewed and applied to boils and wounds. Two websites I visited claimed that arrowheads were dipped in the juice of the berries to make poison arrows. Neither cited a reference, and in the section on arrow poisons in Wicked Plants, Stewart doesn’t mention baneberry. However, that doesn’t mean it didn’t happen.

What do you fear the most? Batman villian, Bane, or baneberry? (photo credit: Comic Vine)

What do you fear the most? Batman villian, Bane, or baneberry? (photo credit: Comic Vine)

References