Plants That Kill: The Little Apple of Death

Adapted from page 118 of Plants That Kill:

The manchineel tree is found from the coast of Mexico south through Central America to Colombia and Venezuela, as well as in the West Indies and Florida. Its caustic properties soon became known to European explorers of the New World, who encountered the tree on beaches. In the sixteenth century, Oviedo noted its danger in his book on the natural history of the West Indies (which incidentally also included the first illustration of a pineapple): 

It has been proved many times that if men carelessly lie down to sleep under the trees, when they rise after a short nap there is a great pain in the head and swelling of the eyes and cheeks. And if by chance the dew from the tree falls on the face, it is like fire, blistering and burning the skin wherever it touches; and if it falls in the eye it blinds or burns them, and the sight is endangered. If the wood is burned no one can endure it long, for it causes much heaviness, and such headaches that all stand away from it, be they man or any other animal.

Leafy branches and immature fruit of the manchineel (Hippomane mancinella), also known as manzanita de la muerte, literally ‘little apple of death’, are a risk for unwary visitors to tropical beaches. Photo Credit: Rob Matthews, Alamy Stock Photo

Since then, numerous graphic accounts of the symptoms that result from skin or eye contact with the latex of the manchineel tree have been published, so we can be left in no doubt of the harm the species can cause. In addition, it produces deceptively apple-like fruit, which are 3–5 cm (1–2 in) in diameter, and when ripe are yellowish green with flushed red cheeks and an aromatic, pleasant-tasting yellow flesh. These, too, can cause contact reactions, and eating the fruit is even more disastrous, as doing so irritates the mouth, throat and digestive tract; deaths have occurred.

Plants That Kill: A Natural History of the World’s Most Poisonous Plants
By Elizabeth A. Dauncey & Sonny Larsson

This richly illustrated book provides an in-depth natural history of the most poisonous plants on earth, covering everything from the lethal effects of hemlock and deadly nightshade to the uses of such plants in medicine, ritual, and chemical warfare.

Featuring hundreds of color photos and diagrams throughout, Plants That Kill explains how certain plants evolved toxicity to deter herbivores and other threats and sheds light on their physiology and the biochemistry involved in the production of their toxins. It discusses the interactions of poisonous plants with other organisms–particularly humans—and explores the various ways plant toxins can target the normal functioning of bodily systems in mammals, from the effects of wolfsbane on the heart to toxins that cause a skin reaction when combined with the sun’s rays. This intriguing book also looks at plants that can harm you only if your exposure to them is prolonged, the ethnobotany of poisons throughout human history, and much more.

A must for experts and armchair botanists alike, Plants That Kill is the essential illustrated compendium to these deadly and intriguing plants.

  • Provides an authoritative natural history of the most poisonous plants on earth
  • Features hundreds of color illustrations throughout
  • Looks at how and why plants produce toxins
  • Describes the effects of numerous poisonous plants, from hemlock and deadly nightshade to poppies and tobacco
  • Explains poisonous plants’ evolution, survival strategies, physiology, and biochemistry
  • Discusses the uses of poisonous plants in medicine, rituals, warfare, and more

Plants That Kill: Deadly nightshade, black henbane & witchcraft

Adapted from page 81 of Plants That Kill:

Deadly nightshade (Atropa bella-donna) is a herbaceous perennial that dies back to a rootstock every year but can grow into a substantial plant during the summer. Attractive, juicy black berries follow its solitary bell-shaped purplish flowers, and conspicuous green sepals form a star at the base. Deadly nightshade grows naturally in Europe, west Asia and north Africa. In northern Europe it is particularly found on chalky soils and close to former abbeys and monasteries, where it was grown as a medicinal plant during the Middle Ages.

Black henbane (Hyoscyamus niger) is native to much of Eurasia and is now widely distributed in temperate regions. Photo credit: A_lya, Shutterstock.

Deadly nightshade is just one of the tropane alkaloid-containing plants that are inextricably linked to tales of witchcraft. Together with mandrakes (Mandragora spp.) and henbane (Hyoscyamus spp.), it is said to have been an ingredient of an ointment used by witches to give them the sensation of flying, and is why witches are often depicted on broomsticks. 

One of the most recent deaths from deadly nightshade, of which there are actually very few, was of a modern-day witch who went by the name of Robert Cochrane. He lived in Slough, United Kingdom, where he started a coven known as the Clan of Tubal Cain, based on a combination of Celtic mysticism and village witchcraft philosophy (American branches are known as the ‘1734 tradition’). Cochrane died nine days after the eve of the summer solstice in 1966, seemingly after having ingested deadly nightshade leaves and sleeping tablets. The inquest into his death returned a verdict of suicide with deadly nightshade. In some witchcraft circles it is believed that Cochrane had appointed himself as a male sacrifice.

Plants That Kill: A Natural History of the World’s Most Poisonous Plants
By Elizabeth A. Dauncey & Sonny Larsson

This richly illustrated book provides an in-depth natural history of the most poisonous plants on earth, covering everything from the lethal effects of hemlock and deadly nightshade to the uses of such plants in medicine, ritual, and chemical warfare.

Featuring hundreds of color photos and diagrams throughout, Plants That Kill explains how certain plants evolved toxicity to deter herbivores and other threats and sheds light on their physiology and the biochemistry involved in the production of their toxins. It discusses the interactions of poisonous plants with other organisms–particularly humans—and explores the various ways plant toxins can target the normal functioning of bodily systems in mammals, from the effects of wolfsbane on the heart to toxins that cause a skin reaction when combined with the sun’s rays. This intriguing book also looks at plants that can harm you only if your exposure to them is prolonged, the ethnobotany of poisons throughout human history, and much more.

A must for experts and armchair botanists alike, Plants That Kill is the essential illustrated compendium to these deadly and intriguing plants.

  • Provides an authoritative natural history of the most poisonous plants on earth
  • Features hundreds of color illustrations throughout
  • Looks at how and why plants produce toxins
  • Describes the effects of numerous poisonous plants, from hemlock and deadly nightshade to poppies and tobacco
  • Explains poisonous plants’ evolution, survival strategies, physiology, and biochemistry
  • Discusses the uses of poisonous plants in medicine, rituals, warfare, and more

 

Plants That Kill: Apocynaceae

Adapted from page 52 of Plants That Kill:

The dogbane family is one of the larger families of flowering plants, and is today considered to contain more than 5,000 species in 366 recognized genera, including those that have, at times, been placed in their own family, Asclepiadaceae. The almost globally distributed Apocynaceae (only northern regions lack native species) has adapted to almost all environments and contains a large diversity of plant forms. 

Species grow as herbs, climbers and lianas, succulents or trees. The flowers are often showy or conspicuous in form or smell, and many species have evolved special structures for pollen dispersal, such as pollinia, coherent masses of pollen grains that are transferred to the next plant by sticking to insect pollinators. These structures are especially elaborate in milkweeds (Asclepias spp.), waxflowers (Hoya spp.) and their relatives, constituting a feature that allows easy placement of these plants within the family (although deciding on the actual genus and species can be quite difficult).

Elephant vine (Strophanthus amboensis) is found from Zaire to Namibia and contains cardioactive steroids. The petals are fused to form a cup at the base and there are five spreading, elongated lobes.

The large number of species and wide geographical distribution of the dogbane family makes it easy to understand why so many plants are used by humans. The showy, waxy flowers of frangipani (Plumeria spp.) have found a place as a constituent in Polynesian lei garlands, the fibres from dogbane (Apocynum cannabinum) have been used to make cloth and string, some species are used in religious rituals, and some genera, such as Landolphia, were briefly important as sources of rubber in the late nineteenth and early twentieth centuries. Several plants in the family have been used as arrow poisons or in traditional medicinal systems, and the Madagascar periwinkle (Catharanthus roseus) is the source of an important cancer drug. 

It seems that most plants in the dogbane family are toxic to some degree, but the reason for this differs between groups of species. Some groups produce cardioactive steroids as the toxic principle, while others produce monoterpene indole alkaloids. Accordingly, the family presents several toxidromes, the combined picture of symptoms in poisonings, with some presenting as acute heart failure with arrhythmias and others giving signs of detrimental effects on the nervous system – for example, seizures, paralysis and hallucinations. As members of the dogbane family are widely distributed and many produce fatal intoxications, the use of these plants in suicides and poisonings is not uncommon in certain regions of the world.

Plants That Kill: A Natural History of the World’s Most Poisonous Plants
By Elizabeth A. Dauncey & Sonny Larsson

This richly illustrated book provides an in-depth natural history of the most poisonous plants on earth, covering everything from the lethal effects of hemlock and deadly nightshade to the uses of such plants in medicine, ritual, and chemical warfare.

Featuring hundreds of color photos and diagrams throughout, Plants That Kill explains how certain plants evolved toxicity to deter herbivores and other threats and sheds light on their physiology and the biochemistry involved in the production of their toxins. It discusses the interactions of poisonous plants with other organisms–particularly humans—and explores the various ways plant toxins can target the normal functioning of bodily systems in mammals, from the effects of wolfsbane on the heart to toxins that cause a skin reaction when combined with the sun’s rays. This intriguing book also looks at plants that can harm you only if your exposure to them is prolonged, the ethnobotany of poisons throughout human history, and much more.

A must for experts and armchair botanists alike, Plants That Kill is the essential illustrated compendium to these deadly and intriguing plants.

  • Provides an authoritative natural history of the most poisonous plants on earth
  • Features hundreds of color illustrations throughout
  • Looks at how and why plants produce toxins
  • Describes the effects of numerous poisonous plants, from hemlock and deadly nightshade to poppies and tobacco
  • Explains poisonous plants’ evolution, survival strategies, physiology, and biochemistry
  • Discusses the uses of poisonous plants in medicine, rituals, warfare, and more

Plants That Kill: Aconite alkaloids

From hemlock and deadly nightshade to poppies and tobacco, poisonous plants have long been used in medicine, rituals, and even warfare. For the next few months, Princeton Nature will be taking a closer look at the evolution, survival strategies, physiology, and biochemistry of the most toxic plants on Earth. Pulling from Elizabeth A. Dauncey & Sonny Larsson’s new book, Plants That Kill, we hope to provide you with just a sample of the deadly and intriguing plants that can be found in this gorgeously illustrated book.

Adapted from page 48-49 of Plants That Kill:

Aconite alkaloids are mostly restricted to a small number of genera in the buttercup family, particularly the aconites (Aconitum spp.) and their close relatives the larkspurs (Delphinium spp.). The presence of the compounds seems to give these plants a strong evolutionary advantage, as the group constitutes about a third of all species within the family. Aconites and larkspurs produce these highly toxic compounds from a substance called geranylgeranyl diphosphate, which is an essential part of the chlorophyll needed for photosynthesis. They can be grouped into three different ‘flavors’, called veatchine, atisine and aconitine alkaloids. The compounds in the last of these groups are the most toxic, which is thought to be due to their ability to pass through fat-containing barriers such as cell membranes and also the skin. This explains why gardeners and florists who, with bare hands, handle the cut stems or crushed material of aconite and larkspur plants in large amounts or for extended periods of time may experience mild symptoms of tingling or numbness.

There are around 250 species of aconite (Aconitum spp.) found in the wild in the northern hemisphere, but they are also widely grown in temperate gardens and sold as cut flowers.                              Photo credit: Alex Polo, Shutterstock

Species of aconite are used to treat joint pain in traditional Chinese herbal medicine in the form of bath additives, rubs and ointments. Their alkaloids can be absorbed through the skin, where they act as local anaesthetics. They may also be taken orally to treat asthma, gastroenteritis and various tumours, or as a supportive and revitalizing tonic. How is this possible, when these plants are very poisonous and small amounts can cause dangerous, or even lethal, effects on the heart and respiratory muscles? 

Before use, the raw material must be subjected to pao zhi (a detoxifying measure), which might include heating and/or soaking with the intention of ensuring maximal therapeutic efficacy with minimal adverse effects. During such processes, the toxic alkaloids are transformed into less harmful compounds, explaining why aconite use has persisted in spite of its high risk of poisoning. However, even though pao zhi is usually performed, a number of patients who take traditional Chinese aconite medicines are hospitalized each year due to poisoning. 

Plants That Kill: A Natural History of the World’s Most Poisonous Plants
By Elizabeth A. Dauncey & Sonny Larsson

This richly illustrated book provides an in-depth natural history of the most poisonous plants on earth, covering everything from the lethal effects of hemlock and deadly nightshade to the uses of such plants in medicine, ritual, and chemical warfare.

Featuring hundreds of color photos and diagrams throughout, Plants That Kill explains how certain plants evolved toxicity to deter herbivores and other threats and sheds light on their physiology and the biochemistry involved in the production of their toxins. It discusses the interactions of poisonous plants with other organisms–particularly humans—and explores the various ways plant toxins can target the normal functioning of bodily systems in mammals, from the effects of wolfsbane on the heart to toxins that cause a skin reaction when combined with the sun’s rays. This intriguing book also looks at plants that can harm you only if your exposure to them is prolonged, the ethnobotany of poisons throughout human history, and much more.

A must for experts and armchair botanists alike, Plants That Kill is the essential illustrated compendium to these deadly and intriguing plants.

  • Provides an authoritative natural history of the most poisonous plants on earth
  • Features hundreds of color illustrations throughout
  • Looks at how and why plants produce toxins
  • Describes the effects of numerous poisonous plants, from hemlock and deadly nightshade to poppies and tobacco
  • Explains poisonous plants’ evolution, survival strategies, physiology, and biochemistry
  • Discusses the uses of poisonous plants in medicine, rituals, warfare, and more

 

Anurag Agrawal: Monarchs & Milkweed in Mexico

Greetings monarch and milkweed enthusiasts from Mexico. This is Part II in my series from Oaxaca, where I am based on sabbatical leave from Cornell (see the first post here). This post follows up on the inspiration I am gaining on sabbatical and is an entryway for my next research and writing projects, following up on my recent book Monarchs and Milkweeds. I expect that the next post will be a detour from this series, as the overwintering numbers of monarch butterflies will soon be announced by the World Wildlife Fund – and this will provide an opportunity to reflect on monarch population trends (are they still declining?) (see last year’s post on the population here).

Oaxaca city is a bustling cultural and culinary capital, tropical, yet it sits at mid-elevation around 5000 ft above sea level.  January is the beginning of the dry season, with many trees beginning to lose their deciduous leaves.  And the “weedy” milkweed of Mexico, analogous to the common milkweed (Asclepias syriaca) of the eastern USA, is blood flower, sometimes called tropical milkweed, Asclepias curassavica.  This species, however, needs moisture and protection from the intense, constant and direct sunlight loved by many other milkweeds.  Here in the middle of the city, where a stream provides both moisture and shade, blood flower is abundant and apparently always in flower.  Hundreds of plants are along this corridor.

Although hundreds of millions of butterflies are currently overwintering in Michoacán (within the Monarch Butterfly Biosphere Reserve), here in Oaxaca, monarchs have a year-around (and apparently non-migratory) population. Adult butterflies were abundant in this stream corridor in January as were many eggs and large caterpillars.

This caterpillar found a quite spot away from milkweed to molt (change its exoskeleton to the larger size).

Butterflies fluttered, twirled around in mating behavior, and females could be seen curling their abdomens in preparation for laying an egg. The fact that non-migratory monarchs are abundant in the city of Oaxaca gives me pause.  I am not sure how long this has been the case.  Are these butterflies a reservoir for the declining migratory butterflies?

In the mid-elevation grasslands on the edge of town, this rare spring flowering milkweed was blooming early. Formerly known as Asclepias rosea, and now renamed to Asclepias senecionifolia (“the milkweed with leaves like Senecio”), it is pretty small and has feathery fine leaves.

This individual has the oleander aphid on it, feeding away (see yellow bugs in the center) and 5 (!) butterfly eggs.  I wasn’t sure which species of butterfly, until I noticed the plant next door.

This mature caterpillar is not a monarch, and I cannot quite tell if it is a “Soldier” Danaus eresimus or a “Queen” Danaus gillipus. Some of the closest relatives of our beloved monarch. Note that although the monarch has two pairs of tentacles, the soldier and queen sports three pairs, likely to sense the sounds, vibrations, and other aspects of its local environment.

As noted in the first post, the nodding milkweed, Asclepias glaucescens, a robus and waxy milkweed can be common in the region.

The creamy white (and large!) flower of the nodding milkweed, Asclepias glaucescens.

 

Leaves can be green to purple, and the prominent venation shows the canals that hold pressurized latex.

Break a leaf and experience the thick and toxic goo.  Both this species and the A. senecionifolia above exude large quantities of latex.

Before I encountered butterflies or caterpillars on the nodding milkweed, I came across this “bug” (a true bug, as it were, in the insect group Hemiptera). Note the highly contrasting red and deep blue, a classic advertisement of the toxic milkweed insects. Colleagues Georg Petschenka and Jürgen Deckert helped identify this as an immature of Largus species. This reminded me that I had previously found a Largus species associated with Asclepias linaria in northern Mexico about a decade ago.  We currently don’t know the extent to which Largus is specialized on milkweed (versus eating other plants) or whether it gains toxicity by sequestering milkweed’s toxins. Perhaps a good PhD dissertation for one my students!

Egg dumping!  This nodding milkweed had, count them, over 9 eggs, an unusual phenomenon for monarchs.  But I didn’t know if these were monarch or solider/queen eggs.  I suspected soldier because I had found solider caterpillars nearby (see above). Nonetheless, after they hatched a few days later, it was clear, they were monarchs!

Nonetheless, I found another soldier/queen caterpillar on a neighboring plant. Note the notch in the leaf made by a caterpillar (the vein drain!)

The soldier (or queen!) in all its glory.

Among the 25 or so nodding milkweeds I found, I came to realize that more than one Danaus species were coexisting. Several caterpillars of each species intermingled.  It is unclear the extent to which butterflies and caterpillars recognize each other as similar or different species, and what ecological consequence this has.  Do they compete?

And lastly, on the nodding milkweed Asclepias glaucescens, were these green aphids.  Not the oleander aphid found on A. senecionifolia above. Some ants collected their sugary excrement, but they were not so heavily tended.  The species identity and relationship with milkweed are unknown.

Later last week, I went on a hike to San Pablo Cuatro Venados, a close by community that sits near the top of a ridge (around 9000 ft above sea level) that forms the western wall of the Oaxaca Valley.  It was chili at the start of the hike, with thin mountain air along the 10 km trek on a dusty dry dirt road.  Just as we were turning around, I noticed this dusty purplish plant.  I instantly knew it was one of the rarer highland milkweeds.

The spectacular but confusing Asclepias melantha. Confusing only because I did not expect to see it flowering until the beginning of the rainy season in June or July.

Note the petals of Asclepias melantha. Although milkweed petals are often “reflexed”, or pushed back to give the flower a rocket-like appearance (see A. senecionifolia above), these petals form a cup around the rest of the flower.  The flowers of Asclepias glaucescens above are not reflexed either, but are less cup-like.

Back at lower elevation in the grasslands, this Asclepias oenotheroides (“looking like Oenothera”) had multiple butterfly eggs.  This species, known as zizotes milkweed, is common the south-central USA and all the way down here in Oaxaca.

Flowers of zizotes milkweed, Asclepias oenotheroides.

A large monarch caterpillar munching away on zizotes milkweed, Asclepias oenotheroides.

 

Alas, I thought I would have a butterfly, but here, as in so many other places, parasites like this fly larva got the best of the caterpillar! These flies are “parasitoids” who lay an egg in a caterpillar and then eat them from the inside out.

 

Anurag Agrawal (photographed, left, with a Malagasy elephant milkweed [Pachypodium] in downtown Oaxaca, Mexico) is a professor in the Department of Ecology and Evolutionary Biology and the Department of Entomology at Cornell University.

 

He lives in Ithaca, New York. For more information, see his blog, publications, and multi-media on monarchs and milkweed.

Quick Questions for Richard Karban, author of How to Do Ecology: A Concise Handbook (Second Edition)

Richard KarbanDr. Richard Karban is a professor of entomology at the University of California, Davis. He is a recipient of the George Mercer Award, presented by the Ecological Society of America for outstanding research (1990) and was a 2010 Fellow in the American Association for the Advancement of Science.

Dr. Karban received a B.A. in Environmental Studies from Haverford College (1977) and completed his Ph.D. in Ecology at the University of Pennsylvania (1982). He is the recipient of nearly a dozen research grants, whose focuses range from population regulation to plant resistance of insects and pathogens. He is the author of How to Do Ecology: A Concise Handbook (Second Edition).

Now, on to the questions!

PUP: What inspired you to get into your field?

Richard Karban: I grew up in an ugly and dangerous neighborhood in New York City. Natural history and natural areas were highly romanticized in my mind. Being an ecologist seemed like an exciting way to escape this life.

What is the book’s most important contribution?

Doing ecological research successfully requires a considerable amount of insider knowledge. We don’t teach these tips in academic classes. This book attempts to provide a simple set of guidelines for navigating the process of generating hypotheses, testing them, analyzing your results, and communicating with an interested audience. In my opinion, this is what we should be teaching ecology students, but aren’t.


“Indeed, confidence and persistence are the most important attributes that separate successful projects from failures.”


What was the biggest challenge with bringing this book to life?

The biggest challenge getting this book to happen was not allowing myself to get discouraged. I teach a graduate-level course in which each student develops an independent field project. The book started as a series of handouts that I gave my students. Each year, I revised my pile of materials. After a decade or so of revisions, I submitted a manuscript but was told that it was too short and lacked interesting visuals and other tools that would make the material accessible. Okay, so much for that, although I continued to add and tweak the content for my class. My wife, Mikaela Huntzinger, read what I had and convinced me that it would be useful to students; she also volunteered to add figures and boxes. Most of all, she encouraged me not to give up on the thing. Indeed, confidence and persistence are the most important attributes that separate successful projects from failures.

Why did you write this book?

I had a terrible time in grad school. I didn’t attend a large research university as an undergrad and I arrived with little sense of how to do research or thrive in an environment that valued research, publications, and grants above all else. Figuring out the culture was a painful process of trial and error. My experiences made me acutely aware of the “game” and made me want to share what I had learned to spare others the same pain.

Who is the main audience?

This book is intended primarily for young ecologists who can use some help posing interesting questions, answering them, and communicating what they find. Undergrads who want to do research and grad students doing a thesis are the two populations who will find the book most useful, although we hope that our colleagues will also get something from it.

How did you come up with the title and cover?

The title is a little presumptuous, but also conveys what we hope to provide in a few clear words – perfect.

The cover reflects my long-standing interest in streams that cut gently through landscapes. The first edition had a photo taken by my collaborator, Kaori Shiojiri, at our field site along Sagehen Creek. This edition features an abstraction of that image that I painted. If we write future editions, they will have further abstractions of that same theme done as a mosaic (Mikaela’s favorite medium) or as a stained glass (one of Ian’s).

Check out Chapter 1 of the book, here.

________________________________________________________________________________________________________________________________________________________

Richard Karban is the author of:

6-6 Ecology How to Do Ecology: A Concise Handbook (Second Edition) by Richard Karban, Mikaela Huntzinger, & Ian S. Pearse
Paperback | May 2014 | $24.95 / £16.95 | ISBN: 9780691161761
200 pp. | 5 x 8 | 8 line illus. | eBook | ISBN: 9781400851263 |   Reviews Table of Contents Chapter 1[PDF]