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DON RAKOW: I'm Don Rakow. I'm the Elizabeth Newman Wilds director of Cornell Plantations. And I want to welcome all of you for what I am certain will be an excellent lecture this evening.
This is our annual Audrey O'Connor lecture. And for those of you who didn't have the privilege of knowing Audrey, she was the first-ever editor at Cornell Plantations. She was the visionary who conceived of the Robison York State Herb Garden. And she was the herb gardener of that garden for many years. She was a noted herbalist with a remarkable memory and collection of herbal books. And I imagine that many of the individuals who are present tonight had the pleasure of spending an afternoon in Audrey's home talking about herbs and looking at some of her many, many books.
As a tribute to Audrey, Cornell Plantations partnered with a local-- I should say regional group of herb enthusiasts, [? ORICA, ?] to create the annual Audrey O'Connor Lecture. We continue to appreciate the contributions that [? ORICA ?] makes to Plantations in many ways, including providing recipes for some of the cookies that we'll be enjoying this evening.
Speaking of those cookies, immediately after this evening's lecture our speaker will be signing copies of her book, Wicked Plants. And we will also be serving refreshments provided by Cornell Dining. We were very fortunate to receive a gift from an anonymous alumnus, who I don't know that I see in the audience tonight. But being anonymous, I won't point him out if I do. But we are very appreciative of that.
So at this time, I would like to introduce Melissa Kitchen, who is a research support specialist in flora culture in the Department of Horticulture, who will be introducing Amy Stewart. Melissa?
MELISSA KITCHEN: Thank you.
[APPLAUSE]
Good evening everybody. Tonight's guest is Amy Stewart, a well-known author of plant books. You might have heard of some of her titles, From the Ground Up-- The Story of a First Garden; The Earth Moved, which is about the remarkable achievements of earthworms; my personal favorite, Flower Confidential; Wicked Plants of course, which she will speak about today; and Wicked Bugs, which you can get excited about coming out next spring.
Amy has received numerous awards and recognitions regarding Wicked Plants. It's a New York Times bestseller. And the American Horticulture Association awarded it book of the year for 2010. There's just oodles of praise in ways that she's been involved in the community. She has been on the Good Morning America show and on TLC's show Cake Boss and NPR and all over the place.
The way that I came to know Amy is kind of an interesting story. Someone gave me the book Flower Confidential that I was talking about being my favorite. And I read that and I realized that we had a lot of people and places and circles in common. She's been to the Dutch flower auction in Holland and to Miami to see the flower importers and even to Ecuador to see [? the ?] flower production.
So in retrospect, that book is almost like a roadmap of my career here at Cornell in a certain way. And I was really touched by that. And I felt like we had this relationship almost like when you read a book or watch a TV show and so you invite someone into your home every week and you think, oh yes, I know that person, when in actuality the person doesn't even know that you exist.
So today has just been an amazing day where I actually got to meet her and show her some of the work and projects that we're involved in at Cornell and have a real relationship. And I hope that you will enjoy her talk as much as I've enjoyed spending my time with her today. So would you help me welcome Amy Stewart?
[APPLAUSE]
AMY STEWART: Well thank you. My goodness there are a lot of you, even in the balcony.
Well I've had a great time today. I've been around and seen many horticultural wonders, including apple trees with more apples on them than I thought was physically possible. I thought we had good apple trees in California, but I was wrong about that, as it turns out.
And so what you're going to find out tonight is that I, unlike, I'm sure, many of you in the audience, I am not a botanist by training. I'm a writer. And I'm very lucky that I get to write about whatever is interesting to me. As long as I can convince my publisher that it's interesting as well, I get to go off and research it and write about it. So things like Flower Confidential came about because I got to wondering about flowers in the flower shop and why they are the way they are and where they came from. And I managed to get to go all over the world and find out the answers to those questions.
And the way Wicked Plants came about was actually sort of related to that, and actually very related to my day here today. I'm lucky that I get to go around and talk to a lot of people who are in the horticultural sciences and wander in and out of greenhouses. And very often I was finding that people who are really into plants, like for their career, sooner or later actually do kind of go over to the dark side and start to--
[LAUGHTER]
--and start to collect really weird and interesting and subversive plants that maybe they're not even supposed to have. This did not happen today, I will say, because I'm sure that people's bosses are in the room. But very often-- very often, and even sometimes in a university setting what would happen is we'd be getting ready to walk out of a greenhouse and somebody would say, "You know what, come back here a minute. I want to show you this thing I have. Now don't tell anybody I have one of these, but take a look at the--" there was always something weird and sometimes something really quite naughty in a way, something subversive or something a little bit immoral.
And I just got to thinking, there really is this dark side to the plant world, right? I mean hemlock killed Socrates. And I sort of started making a list in my head and realizing there really is a certain amount of murder and mayhem in the plant world, and it would be interesting to tell those stories.
So the challenge for me in defining what wicked meant was it had to have some terrible effect on humans. It had to be about something that happened to us. So I was really looking at plants that were poisonous, deadly, painful, maybe even offensive in some way-- plants that explode, plants that smell bad, plants that catch on fire, things like that. And in every case I needed a good story. That was how I was going to narrow it down, because otherwise the book would have been 4,000 pages long.
So how was I going to pick and choose? I was going to pick up plants that had a really great, very human story behind them. So I was always looking for a victim or a villain or a body buried in the backyard. That was my challenge with every one.
So for instance, the first plant in the book, Aconitum-- great, great plant. We grow in our gardens and yet it's really pretty highly toxic. But I couldn't find a good story for monkshood. And that was really frustrating me because I very much wanted to include it, but I couldn't unless I had some great story.
And I just happened to be in London when the Pakistani cricket coach Bob Woolmer died under mysterious circumstances. I don't know if any of you follow cricket-- I mean, I don't really, but when you're in London you sort of can't help it. And so there's all this speculation about his death and what might have happened to him. And it appeared that he had been strangled. But the problem was that there was no signs of a struggle. And it was like, well how do you strangle a guy that big and have no signs of a struggle?
So a rumor went around for a while that he had been poisoned with monkshood, aconite, which would have paralyzed him and made it easier to strangle him. And I found myself thinking, oh please let it be monkshood.
[LAUGHTER]
The math has passed on. He is gone. We can't bring him back. So please couldn't it be one of my plants? And it wasn't unfortunately. Well, they decided that he died of a heart attack and that there was no foul play involved as a matter of fact.
So that was always my thing. So I was always sort of taking delight in other people's misfortunes. Someone would come up to me and say, "Did you read that article in the New Yorker about the guy who was out on a hike and he found this bush and he ate the berries?" I'm like, "Oh that's fantastic. Really? Well When was that? I've got to go back and get that." So I love to this day to collect these kind of stories.
So you will see that that's really what this is is a set of stories and that is a highly selective list. So you all will see many plants that you know to be poisonous or evil in some way that are not in this book simply because they didn't make the cut. I couldn't find a good-enough story to go along with them.
So I'll start by making a point that's probably obvious to a lot of you which is that these plants are all around us. They're not necessarily in a remote jungle halfway around the world. So for instance castor bean-- which is so beautiful and I've seen lots of it today-- contains ricin. The seeds contain ricin, which is really one of the most deadly plant poisons on the planet. And here it is in Chicago, right down Michigan Avenue, right in the middle of everything. I always love seeing my wicked little plants out in the middle of everything.
Also here these Datura, these nightshades, which are hallucinogenic and they can ultimately slow down your breathing and really stop your heart, send you into a coma, and kill you if you were to ingest enough of them. And here they are at the Chicago Public Library just spilling out of every window box. And I love these people walking by having no idea what they're passing by.
And another Datura, this is actually in Albuquerque. And I just want to make the point, it's not just that these plants are out in parks but that they're in our homes and gardens as well. I went to visit my friend Annette in Albuquerque. And I pull up in the driveway and the whole front yard is covered in this beautiful Datura. It's a weed in Albuquerque. So if you don't pull the weeds in your front yard, this is what you end up with.
And she's got these two little boys, little toddlers. And I said, "Annette, you've got to get rid of that. You can't have that in your front yard. If the kids eat them, it would be very bad." "Oh, it's not a problem. Don't worry, the kids don't play out in the front that much. It's not a big deal. They're not going to eat the plants." I cannot convince her to get rid of this thing.
And from my perspective, kids live very protected lives, right? We go around-- any of you with kids or with grandchildren you know the little covers over all the electrical outlets. And I mean, I go to visit my friends with kids and I can't turn on the faucets or start the oven or open any cabinets or anything, right? The whole thing's been so childproofed that it's nonfunctional. We go to great lengths to protect our children and to keep them safe, but we'll just let anything grow in the front yard.
So I was unable to convince her the whole weekend. And so finally as I was getting ready to leave I said, "OK, well, here are just a few tips, a few symptoms, things to watch for if the kids were to get into the Datura. If their faces get real red, if they seem kind of dizzy and they're talking kind of nonsensical like they're not making a lot of sense, if they have trouble breathing, or if their heart stops--"
[APPLAUSE]
"--those would just be a few things to keep in mind." And then she finally got it. Then she was like, "Honey, get out here." So her poor husband had to glove up and get all the Datura out. But it's surprisingly hard to convince people.
So here's what I think. I think part of it is we just assume if it grows out of the ground then it's natural, right, because it comes from nature. And if it's natural, that means that it's good, which sort of overlooks the fact that nature, the plant kingdom, produces strychnine and ricin and cyanide. They're very natural, but that doesn't make them good for us. And I just think we have this assumption that whatever grows out of the ground is there for our enjoyment alone and must be there for us. And so we get this misguided sense of risk. We evaluate risk in such a funny way.
So I got to thinking about those little covers over all the electrical outlets. And I thought, well just how often does a toddler actually electrocute themselves by sticking something in an electrical outlet? Well it turns out annual injuries from electrical shocks, 3,900 a year. And for the most part these are not toddlers sticking things in electrical outlets, right? These are adults pretending to be electricians who really have no business doing that.
Annual reports of plant poisonings, almost 69,000 a year. Now that does not mean that 69,000 people a year are dropping dead after ingesting a poisonous plant, but something happened that was serious enough that they called it into a poison control center or it got reported at an emergency room or a doctor's visit. So these plants really are all around us. And I think that sometimes we don't really think about the risks posed by the plant kingdom.
So I want to show you a few of the places I got to go to do research for this book. There was a lot of very fun research involved. The Alnwick Poison Garden in Northumberland, England, very far Northern England, it's a wonderful place. The Duchess of Northumberland decided it would be charming to plant a poison garden around her castle. So she did. And as you can see, it's very over the top, the skull and crossbones. And you can only go in with a guide. And they walk you in and then they slam the gate behind you and they lock you in. And you have to sort of follow this guy around and go from plant to plant-- so very dramatic.
And they have a lot of plants that are very sort of familiar poisonous plants-- hemlock, Conium maculatum which you guys have, right? This grows around here. And this is, of course, the plant that killed Socrates. So Socrates was put to death for corrupting the youth of Athens, among other crimes. And for a long time people weren't quite sure what they meant when they said that he took hemlock, that hemlock was the poison that killed him, because hemlock could have meant a lot of different things.
There were some very brave doctors in about the 1800s that started deliberately ingesting poisons and recording the symptoms to find out-- yeah. I mean, you think it's hard being in the medical profession today, I mean-- but how else are you going to really get this data? So we started to figure out that Conium maculatum, that very hemlock, causes this kind of slow paralysis that was really in keeping with how Socrates died. So that's sort of how we know that this is the very plant that killed him.
Another very interesting plant they have at the Poison Garden in Alnwick is cannabis. And they got special permission from the British government to grow it. And I love that it has to be in jail, right?
[LAUGHTER]
As a condition of its release it has to be locked up behind bars because it's been very bad and it must be punished. But they actually do drug education in the garden. This is very British I think. They hire these actors who come out into the garden and act out the parts of people who have succumbed to the evils of plants such as these-- seriously. And they bring in busloads of schoolchildren to watch these enactments happen in this poison garden. Can you imagine? I mean, what an impression it must make.
Anyway, it's a fascinating garden. They have these flame-shaped beds. It's this walled garden. It's very Gothic and dark and wonderful.
And this is her castle. This is the Duchess of Northumberland's house. And if this looks familiar to you, that's because this is Hogwarts. Yes, this is where the Harry Potter movies were filmed. So it's very fun to take the train up from London on the Hogwarts Express and check it out and then go see the poison garden.
Another thing, I spent a lot of time hanging around botanical gardens and herbaria and talking to people about how specimens are still collected even today. Like right now, today, there are people out in the world collecting plant specimens and very often just pressing them between the pages of the day's newspaper and sending them in somewhere to be sort of cataloged and kept track of. So there's a lot of important information in institutions such as this.
The Chelsea Physic Garden is another great place to go and see poisonous plants. This was an apothecary's garden in London, starting in the 1600s. So if you lived in London in like the 1600 or 1700s and you had the misfortune to get sick, this was Rite Aid. This was Walgreen's right here. If they didn't have it, you were kind of out of luck.
So they grew a lot of medicinal plants here, but they also grew poisonous plants. And one of the reasons for that is that the line between medicine and poison has always been pretty thin. And it was especially thin in those days, but also because of all the plants you didn't want to make a mistake with identifying, the poisonous plants were pretty important if you were going to prescribe something. So it helped to try to have some living specimens to look at.
So here's henbane, Sir Hans Sloan, very famous plant explorer, reporting about children who were poisoned with henbane. Very often I'll show this slide to someone and inevitably someone will come up to me afterwards and say, what's the name of that plant that lets you sleep for two days and two nights?
[LAUGHTER]
Forget about it. Do not try this at home. Henbane was actually one of the plants used as an anesthesia back in the days before versed and other such lovely drugs. You would sort of get this sponge of herbs placed over your face and maybe it would knock you out before the surgery or maybe it wouldn't. And maybe you'd wake up afterwards and maybe you wouldn't. It was all very dicey. It makes me very grateful to live in the days I live in.
Here are a few. So these were actually on display at the Chelsea Physic Garden. And we're going to talk about these a little bit. So over there is castor bean, which we've already seen. Castor bean seeds contain ricin, very deadly poison. And there's Strychnos nux-vomica, the strychnine tree. That's what strychnine looks like in its raw form. And the Calabar bean, which I'll tell you a little bit more about, that's a very poisonous vine in Africa.
And the cola nut-- so pretty much everyone in this room has already poisoned themselves with a plant poison today-- caffeine, right? Most of us have already had some. That's an example of a toxin that plants produce. One or two cups is just the thing for most of us to get going during the day. If you were to have a hundred cups of coffee, that would be enough poison to kill 50% of you. It turns out that's how poison levels are measured. What's the amount of poison necessary to kill 50% of the people it's administered to? I don't know who came up with that idea.
But anyway, so the cola nut is a little caffeinated nut. And so Coca-Cola, that's the name of two plants. And this is the cola part of that. So the poison in that case is caffeine.
And another great place I got to go for this research was the USDA Poisonous Plant Research Laboratory. I mean, who knew this place even existed? And they were very surprised when I called up and said that I was coming and I would like a tour. I don't think they get a lot of calls like that. It's kind of in the middle of nowhere. It's very X-Files, this sort of high-tech laboratory out in the middle of the desert, very much under the radar.
But they started out trying to help ranchers with livestock. They're ranching over millions of acres of the American West. The cattle and the livestock are ingesting plants that are possibly poisonous. So they were just this little outstation. And since then they've grown into this incredible research facility.
So they go out and they collect these plant specimens and they take them back to their high-tech whiz-bang laboratories and analyze them to try to figure out what's going on and really have made some very interesting discoveries. So I'll just tell you about one of them. Isn't she a sweetie?
Ranchers had figured out that their goats were grazing on some kind of plant that was causing them, if they were pregnant, was causing them to give birth to kids with cleft palate. So they call in the folks at the USDA who go out and do their research, do what they do out in the field, and they figured out what the plant was. The plant is a Nicotiana. It's tree tobacco. And if goats are pregnant and they graze on this plant during a very narrow window of their gestation-- it's only two or three days. And they eventually got it down to-- they really narrowed it down to two or three hours of their gestational period-- they will give birth to a kid with cleft palate.
So they figured that out. They figured out what was causing it, what the precise mechanism was, and so on and so forth. And that was fine and they could help the ranchers figure out how to keep the goats off the plants when they're pregnant and they sorted all that out. But then they realized, now we have a way to cause cleft palate to happen. And nobody else had been able to figure that out.
So they call a team of surgeons out here, I think in Providence actually, who work on cleft palate and said, how would you like some goats to experiment on? And surgeons said, that would be fantastic. Send us a pregnant goat.
So they did. They put her on a plane and they flew her out to Providence, Rhode Island, and very quickly learned that it's much easier to fly surgeons to Utah--
[LAUGHTER]
--than-- yeah. It doesn't take these guys long. They pick up on stuff pretty quick.
So after that, they built this state of the art surgical facility there in Logan, Utah. And the surgeons come out.
So here's what they do. They have the goat. The goat is pregnant. They feed her the plant during this particular moment her gestation so that the little fetus has cleft palate. And the surgeons go in, and they've developed this technique where they can go in and they cut open the mama goat and cut into her uterus and correct the cleft palate in the little fetus. And they sew it all back up and she goes on with her pregnancy and she gives birth to a little baby goat that is perfectly healed, no cleft palate and not even a scar, because fetuses are capable of scarless healing.
So that's amazing, except that for people, very often we don't know that a child has cleft palate until the child is born. And also in impoverished countries, we don't exactly have a team of surgeons on standby all the time. So what they also did is they allowed some of the little baby goats to be born with cleft palate and they developed this appliance that kind of goes up in the roof of the mouth that has a little knob that sticks out of the side of your face. And it can be tightened up occasionally. And what it does is it reduces the number of surgeries required because you can use this appliance to sort of force everything back in place rather than having to go in and operate over and over and over again, which is what's normally required for cleft palate.
And I actually met a woman not long ago who told me that her granddaughter has one of those things in her mouth right now. So they're in use today, and it's all because of a goat and a poisonous plant. So you never know where you're going to go with this kind of stuff.
So some of my favorite plants from the book-- castor bean, which I've already mentioned, I just love. I think it's so beautiful and it's so very deadly. Here it is. This is the Navy Pier in Chicago. So family tourist attraction, little kids running around, and here's this plant that produces these very, very toxic seeds. Ricin interferes with your cells' ability to make and use proteins so that your cells just die and you have massive organ failure. It's actually a pretty terrible way to go.
Anyway, so here it is out in the middle of this tourist attraction with the roller coasters and all this stuff. Does anybody remember the case in Las Vegas a few years ago? A guy had castor beans seeds in a hotel room in Las Vegas and he was he was extracting ricin from them. Well, here's what the police showed up in when they were responding to the presence of castor bean seeds. There they are in their hazmat gear. So it's always funny to me, the ways in which we sort of live with or don't live with certain risks.
The sheriff in the Las Vegas case was quoted in the media as saying that there's no lawful reason why anyone would possess castor beans seeds. And I just thought, well, unless you're a gardener. Open a seed catalog. Go to a garden center. What, are we all suspect all of a sudden? It's pretty interesting.
Another one that I love, the strychnine tree. So you remember I said that I always had to have a victim or a villain. So in the case of the strychnine tree, I was very happy to actually find a serial killer. Dr. Thomas Neill Cream murdered his patients using strychnine and was eventually caught and hanged for his crimes. Justice was definitely served in this case. But strychnine is another very interesting poison. It goes to work on the nervous system and send this unstoppable flood of pain signals through the nerves, so a really very agonizing way to be poisoned.
But Cream was kind of an interesting sort of mysterious figure. For a long time people thought that Thomas Cream and Jack the Ripper were the same person. And I was thinking, oh, I would love to get Jack the Ripper in this book. Is that possible? But no, as it turns out, not the same guy.
This is another one, probably a plant pretty well known to you guys. This is the weed that killed Lincoln's mother, white snake root. So here's what happened. In the early 1800s, actually well into the late 1800s, cows would graze on this plant. And the cows would get sick and the poison would end up in their milk and people would drink the milk and get sick and die. And that was called milk sickness.
And milk something was very terrifying. People didn't know what caused it at first. They figured it was something in the milk, but you couldn't very well not drink milk. I mean, if it was just sort of you and your family on your little plot of land and you just sort of had the one or two cows and they would wander out and eat whatever there was to eat that day and come back and whatever was in their milk, that was what you drank, right? That's sort of how it worked. And that's what killed Abraham Lincoln's mother, Nancy Hanks Lincoln. Lincoln was only nine years old when she died. And he actually had to help his dad make the coffin and actually make the nails. So really a very sad moment.
And I just look at this plant and I think, here's this plant that changed the life of someone who went on to change all of our lives. It's a plant with a really tragic and interesting role in history.
And actually, again, I really sort of have to credit the USDA on this one too. Farmers bulletins-- this is something you guys are going to be very familiar with-- but farmers bulletins played a real role here because it took a long time to figure out what was going on, and news traveled slowly. So I was reading the archives of the Chicago Tribune back into the mid-1800s. And a farmer figured it out and said, it's white snake root. You got to keep your cows away from it. 20 years later in the Atlanta Journal-Constitution, people are still dying of milk sickness and they're saying, if only we knew what caused milk sickness. And I'm thinking, well if only you people would pick up the Chicago Tribune once in a while you would know.
But they couldn't. News traveled very slowly. And those farmers bulletins that the USDA put out played this very vital role of getting this news out, saved people's lives.
Here's a very cool one, ergot. So this is actually a fungus. I did sneak a few nonplant things in here, including some-- I just knew I would not be able to talk my publisher into Wicked Fungi and Wicked Bacteria and Wicked Protozoa and all that kind of stuff. So I had to just work in what I could.
So ergot is a fungus that grows on rye. It contains a precursor to LSD. And it survives the process of being baked into bread or brewed into beer or anything like that. So there used to be these outbreaks of what was called St. Anthony's Fire in the Middle Ages or dancing mania. Whole villages would kind of go crazy all at once. And it really was this sort of LSD-like effect on people. So it was like you know the whole village was suddenly at Woodstock only they didn't mean to go, but there they were. It must have been terrifying, but really quite dangerous as well.
So we will never know for sure. We can only speculate, but there has been some interesting speculation that what happened in Salem, Massachusetts in 1690s was-- we had all these girls suddenly going crazy all at once and nobody could figure out how to explain their bizarre behavior. And the only logical explanation, of course, was that they had been bewitched. I mean, what else could it possibly be? So we had the Salem witch trials and people getting sent off to the gallows.
Well now looking back, it does look like it was a very wet winter. It would have been the right conditions for an outbreak of ergot in the fields. Europeans had kind of figured out what was going on at that point but news would not yet have reached the colonies, so it would make sense that they wouldn't have really known. So it's possible at least that 19 people went to the gallows in the Salem witch trial-- an estimated 50,000 died of ergot poisoning in the Middle Ages, all because of a insignificant little fungus that attached to rye in a loaf of bread. I love that.
Another food-related one-- I was very interested in this idea that there are foods that we eat all the time that have some poisonous component to them. So I did this whole section called "Deadly Dinner" of foods that we think of as safe but that really kind of aren't.
And so corn's a very interesting one. So Europeans came to this country for the first time and encountered a lot of strange and interesting new plants. It was one of the really fascinating stories I think about the Europeans arriving here was all the strange plant life they encountered for the first time.
And my ancestors were in that group, so I can say that. I suspect that there are some of you here who can trace their roots back to Europeans who came early to this country. I think we can admit at this point that we did not always send our best and our brightest to the New World, right? I mean, mistakes were made, right, lots of them, and really some interesting little mixups in the plant world in particular.
With corn, so they come and they see this very tall grass and it's some sort of grain. And they didn't even have any real words for it. Columbus goes back and tries to explain this stuff to the queen and he's like, well yeah, it's kind of like a grain only they're the size of peas. And everybody's like, oh sure, they're the size of peas. No one can even imagine there's a grain as long and thick as a man's arm.
So they were enchanted with corn, said to the Native Americans, thank you very much, we'll take this. Took it back to Europe, planted it. It. Became sort of this staple peasant food in Europe, particularly in Eastern Europe. It also went to China at about that time.
And what they had failed to ascertain from the locals is that you cannot eat a diet of entirely corn morning, noon, and night all winter long. And this being a food that you can store up for winter, it actually became possible that you would be eating corn morning, noon, and night in the middle of winter if that's all you had. What the Native Americans knew was that you had to combine corn with other foods in order to make it safe to eat or you would end up with a very severe niacin deficiency that would cause all kinds of strange symptoms.
So the Native Americans were combining it with some sort of slaked lime, some sort of calcium hydroxide product, which could be ashes from a fireplace. There are lots of ways that you can derive this sort of naturally occurring mineral-like substance. The traditional Mexican recipe for tortillas still has the addition of some kind of product like that in them.
So the Europeans didn't know that. So people were eating corn morning, noon, and night. They were getting this very strange set of symptoms. This was called pellagra. Again, nobody really knew what was causing pellagra, but the symptoms were, you sort of couldn't go out in the sun because your skin would break out. You couldn't digest normal food. You had this weird manic behavior. You're up all night and sleeping all day. And generally you just looked really ghastly and pale and morbid and awful and then you died. As you can tell, this is sort of where all these stories are going. You die.
So historians now believe that it was pellagra victims who were the source of the Dracula myths in Eastern Europe, the vampire stories. They didn't all look like Bela Lugosi, but they did have a lot of these same characteristics. So it took a while to figure out that it was corn and that there was this whole thing about needing to eat it in combination with other foods, none of which is an issue for any of us because we eat far-too-varied a diet for this to be a big deal anymore.
This is another great one. In this case, what we're talking about is really just pond scum. Do you guys have outbreaks of toxic blue-green algae in your waterways? Is that a thing here? It's a big thing on the West Coast. You'll see signs, don't go in the water, it'll kill you. And so we're basically talking about pond scum. This is a natural thing that kind of cycles through and happens.
And so the story here, very interesting, in Santa Cruz, California in the early '60s, people woke up in the middle of night one night to the sound of seagulls slamming into their houses, hitting the ground, flying into cars. People went outside with flashlights to try to figure out what was going on and the seagulls were so disoriented by the flashlights so that they appeared to be flying right into people.
[THUMP]
Oops, flying right into people--
[LAUGHTER]
--because they were just so disoriented. So it was this very strange thing. And no one knew at the time what caused all these seagulls to just sort of crash to the earth.
But now marine biologists have looked back at this incident and realized that what happened was there had been an outbreak of toxic blue-green algae in Monterey Bay. The fish ate it. The birds ate the fish and they got sick and disoriented and started feeling awful and they all sort of came crashing to the ground. So that kind of cleared up that little mystery.
But the cool thing about this is that there was this filmmaker living in the Santa Cruz Mountains at the time.
[LAUGHTER]
He had been trying to figure out how to adapt this Daphne du Maurier short story called "The Birds" into a screenplay and he had not been able to figure it out. And then he opens the paper one day and he sees what happened in Santa Cruz and he's got his movie. So anytime I can work Hitchcock into a gardening book, I'm very happy. So there's your Hitchcock.
Oh, this is a great one. So Claudius I, emperor of Rome, died after dinner one night. And he was surrounded by many people. I guess when you're the emperor of Rome, there's always sort of a lot of people around. So a lot of people were able to describe the circumstances of his death.
And so there was recently a conference, a panel of toxicologists who were analyzing the descriptions of how he died and trying to piece together what might have happened. And they decided that it was some kind of mushroom poisoning. They couldn't say for sure what, probably some kind of Amanita, but they didn't really know for sure. But that was very in keeping with his symptoms. And he did have mushrooms that evening for dinner.
And his fourth wife had made dinner for him that night. So at this conference they ruled that his cause of death, he died [LATIN], which means that he died of one too many wives.
[LAUGHTER]
That can happen. So watch out husbands in the audience.
So here's the Calabar bean. So the Calabar is a poisonous little vine that grows in Africa. And when James Livingstone came back from his journey across Africa, he reported to the London papers. And I went back and sort of read through the accounts upon his return of some of the things that he saw. And he talked a lot about the Calabar bean as a form of criminal justice in Africa.
So the way this would work is that if you were accused of a crime, you would be fed this poisonous bean. And if you died, that meant you were guilty, and you had therefore already been punished and we were sort of done. And if you lived it meant it you were innocent and you were free to go. So remarkably simple way to carry out criminal justice I think, but it was open to some sort of interpretation. The judge had some leeway as to exactly what seed you would be fed. So there was already some corruption even in that system. But it is beautifully simple. I often worry that if our California governor ever got wind of that, that he might just write the whole criminal justice system right out of the budget all at once and solve our budget woes.
OK, so the most painful plant in the world, this was a very interesting question for me. People always say, oh, wicked plants, so are you going to have poison ivy, poison sumac, poison oak? And I was like, yeah, but that's not the most painful plant in the world. I think that the most painful plant has to be the giant stinging tree in Southern Australia which is covered with these very fine little peach fuzz-like, nettle-like hairs. It looks like you could just pet them.
But if you look at them under a they look more like this, yes, little hypodermic needles with a tiny little dose of a very potent neurotoxin in every one. And they get up under your skin and you can't pull them out. This is not like a big thorn that you can see and pull out. They get under your skin and you can't remove them. The pain is said to be the worst pain, the worst sting that you can possibly imagine. And the pain lasts for up to a year. And it can be reactivated by heat or sunlight. So you walk out in the sun, you get in a hot shower, it all comes right back.
And the other interesting thing too is that the little hairs will actually break off and float around in the breeze. So you don't even have to touch it. You could get some in your eyes or up your nose or in your mouth just by sort of walking near them.
I talked to the botanist who's specialty is this plant. And I asked her if there's any sort of treatment that she developed out in the field for being stung by one of these. And the only thing she's been able to recommend is one of those wax hair removal strips. So you women know what I'm talking about. I want you to imagine that pain and then you wax it on top of it right after that. She actually recommends a shot of whiskey before you do that. So that would be the first aid kit, whiskey, wax strip, there you go.
Invasive-- so everybody asks me, well, you're going to include invasive plants, right? And I was like, well, I mean, they have to be so invasive that they're really creepy. They have to just send chills up my spine in order for me to include them. Because otherwise, again, the book would be 4,000 pages long.
This is one that I thought would be neat to include. What you're looking at is basically like seaweed, right? And this particular species likes warm-water oceans and could never really do well in a cold-water ocean. So there was an aquarium in Germany that had a cold-water aquarium and had one specimen-- I'm talking about one individual plant-- that for whatever reason was very happy in this cold-water aquarium.
So the other staff, they all go around and visit each other. And so the other staff saw that and said, man, that's really beautiful. I love that. I don't know how you're getting it to grow in there. Can I have a cutting? Sure, yeah, take one.
And pretty soon it's all over Europe. And it ends up at Jacques Cousteau's aquarium in Monaco where somehow it goes overboard. They're cleaning out the tanks, something. A little bit escapes. And because it's weirdly adapted to cold water, it's doing very well. It immediately starts to spread. And it turns out that this stuff can get to 30 feet deep on the ocean floor. It's killing out all other plant life. It's toxic to fish, so fish cannot eat it. And it's freakishly easy to spread.
So you drag an anchor through it, you run a propeller through it, you get any little bit of it on your boat and take it somewhere else, it just starts growing new roots immediately. And it has gone everywhere.
There was recently a little outbreak of it off the coast in San Diego. And they actually sort of tarped over it on the ocean floor and injected chlorine into it to kill it. Like that's how bad it was. It was better to put chlorine in the ocean than to have this growing in the ocean.
So a very creepy plant. They've done DNA analysis of it and it's all the same specimen. It hasn't mated. It's just the one plant all over the world-- very creepy.
So another thing, so people would always say, oh, wicked plants, you mean like Venus flytrap? And I was like, well, I don't know. I mean, that's not very wicked to eat a bug, big deal. But I had heard that there was a carnivorous plant that could eat a mouse and that mouse skeletons had been extracted from the jaws of these plants. And I thought, all right, that's pretty good. If I can confirm that, it's going in the book. But I couldn't. I could not confirm it. I could not find any reliable account that that had ever happened.
But as I'm working on the book, it happened in a conservatory in France. So visitors are walking through the conservatory. They smell this terrible smell and they call the staff over. And we've reached the gross-out portion of the evening here, I have to warn you. They actually pulled a little dead mouse out of this plant. And anyone who does not want to see a little dead mouse being pulled from the jaws of a carnivorous plant, you need to avert your eyes right now. You've been warned, because here it comes.
[GROANS]
I know. Look at the size of that thing.
So what happens is that the mouse drowns, of course. It drowns in the collected rain water and sort of little digestive enzymes that are inside this thing. It's not like the plant has teeth and is chewing it up and spitting the bones out, which would have been great, but anyway. Yes, I know, you sort of wonder, like, huh, where's that going? Yikes.
OK, it's safe to look again. There will be no more carcasses in the rest of this presentation.
I did want to include some very common garden plants. And so oleander for you guys is not so common a garden plant because it doesn't overwinter. But certainly on the West Coast and throughout the South, oleander's everywhere. It's a great example of a plant that you might plant it all around your kids' elementary school. It's all over the place. It contains cardiac glycosides that will stop the heart.
And this is another one. I go to visit my brother in Los Angeles and we walk up to the front door and here's this big oleander right by the front door. And he's got two little toddlers. And I said, "Jason, you should get rid of that plant. That's very poisonous, very dangerous for your kids." "Oh, the kids aren't going to eat the plants?" Like what do I know? Don't worry.
Well in fact in Southern California just a few years ago, two toddlers were found dead in their crib after having ingested a little bit of oleander. So it does happen. The flowers are sort of a bright, attractive color. So it can be a temptation.
And also there was a woman also in Southern California who attempted to murder her husband by making him oleander soup. And it didn't work. He ended up in the hospital for about a week but he survived. So then she put antifreeze in his Gatorade and she finished him off that way. She's on death row right now. She's 1 of 15 women on California's death row, and the only one I know who attempted murder by plant anyway. And I don't have the oleander soup recipe either, so don't ask me for that afterwards.
Plants that are poisonous to pets-- so this is something that should be very near and dear to the hearts of many people here at Cornell. When I was researching the book, one of the first places I called was Cornell's poisonous plant garden because it's one of the only ones in the country. Has anyone not been to the poisonous plant garden here at Cornell? Oh, you totally have to go. It's very cool. It's just getting out of season right now. I don't want to oversell it because it's about to be winter. But it is great.
And it's real important that people actually see the plants. Even a photograph can only tell you so much. So it's great to be able to walk somebody out and go, is that the plant that's in your yard that you think your cat or your dog might have eaten? So very cool thing to have a poison garden of any kind.
Well anyway, as for pets, I think people are more concerned about their pet's safety when it comes to poisonous plants than their children's safety. And I don't want to speculate as to exactly why that may be, but I think we sort of assume that our kids are as intelligent and resourceful as we are, but we know our pets will just sort of get into anything. And in fact there are a lot of very common plants that are pretty toxic to pets.
It would be a mistake to assume that your pet, being an animal, somehow naturally knows what plants to eat and what not to eat. I think people sort of assume, well, the plants are from nature and the dogs are from nature so they know. But they don't. They don't know. Your golden retriever is not native to Ithaca and the plants that your golden retriever's going to encounter are not native to wherever they're from. They have no shared genetic background to rely upon. So your pets do not know.
I'll just give you a couple of examples. But of course you have a wonderful resource right here, being at Cornell. But in addition to that, the ASPCA has done a very nice job of having an animal poison control center. And you can go on their website and look stuff up there as well.
But as an example, the sago palm, very toxic to dogs. Now for you guys this would mostly be a houseplant or a conservatory plant. But again, on the West Coast, in the South, you can grow these outdoors. I regularly get emails from people whose dogs died after they chewed on a sago palm. People say, I had no idea. If I had known it was so toxic to pets, I wouldn't have bought it. I would have bought a different houseplant. So people don't know.
For cats, lilies. Lilies are very toxic to cats. They cause kidney failure. Nobody really knows what lilies have against cats particularly, like why cats and why kidney failure and why lilies? But I met a guy just this last year who came home and this vase of lilies was knocked over on the floor. You know the way cats will do, they jump up on the table, they knock that thing over. And some of it had clearly been kind of munched on or messed with. And he goes me finds the cat and the cat is in active kidney failure and died, didn't make it.
So I think the thing with your pets is that you just have to know if they're a nibbler or not. Some pets are and some aren't. My cat is so fat and lazy, he would never walk past his food dish for a meal. He knows where food comes from, and it comes from the box. But other animals, they get into everything.
I did include some houseplants just to make the point that just because something is sold as a houseplant does not make it a breakfast food. And I think this is an important distinction. You don't have to run screaming from a plant just because it's poisonous. You just need to not eat it for breakfast. That should be a pretty simple thing to remember I think.
Go into your bathroom when you get home tonight and look around and you'll see conditioner and shampoo and shaving cream and razor blades and Band-Aids and light bulbs in the light fixtures. None of these things are food, right, for you to eat. But you're not terrified of them. You just know not to eat them. So the same is true of houseplants. You don't have to be scared of them.
Just remember that the reason plants get selected as houseplants is because they happen to like it in sort of year-round 70 degree temperature. They don't mind the low light. And they don't go through any ugly deciduous phase where they drop all their leaves and look terrible for six months. We would not put up with that in a houseplant. So they end up being these kind of tropical plants, many of which contain calcium oxalate crystals that can really irritate your mouth and throat and give you a lot of gastric distress and could, in large-enough quantities, be fatal, but would probably just make you regret having eaten them. So don't eat them. That's all you need to know about that.
Allergens-- so I don't know if you guys know this guy Tom Ogren. He's written a wonderful book called Allergy-Free Gardening. I talked a lot with Tom as I was writing this book. I think people overlook the plant in their backyard that might be causing their seasonal allergies.
Again, I go to visit some friends one time, and everyone in the house is sick. They've all got allergies. The parents, the kids, they're all doped up on all kinds of medications and they're missing work and missing school. Everyone's miserable. And I look out in the backyard and here's this row of cedar trees that are just yellow with pollen. And it's all over the walkways and it's up the side of the house and it's stuck to everyone's bedroom windows.
And I said, "I don't know much about your local flora in this part of the country, but I think that's what's making you all sick. I'm just guessing here." And they kind of went, "Oh yeah, you're probably right." And it's like, well get rid of them. Cut them down. This is not heritage oak. This is not a plant that your grandfather brought from the old country. This is what was on sale at Home Depot the weekend your contractor was putting in the landscaping in your subdivision. These are not valuable or important plants. You can spend a few dollars at a garden center and put in something that will not make you sick.
Now of course the thing that has happened-- and I'm sure a lot of you guys already know this-- is that when Dutch elm disease wiped out our wonderful American elms and decisions were made about what trees to replant in our cities and our streets and our parks all over the country, a lot of people went for plants that are exclusively male so that there wouldn't be any of those messy females dropping berries and fruit the way they do, because what a mess that is.
So what do you do when you get a bunch of males together all in one place with no female? What do they start doing? They just start spewing pollen out into the air, just never ending. They just know that there is some woman somewhere who will be so glad to have it, right? And they just continue to give their gift. That's what they have to give.
[LAUGHTER]
And as a result, there are cities that are just uninhabitable for allergy sufferers. And go to the garden center and try finding out the gender of the plants at the garden center, if they have a gender. I mean this is a very sophisticated horticultural audience. You know that many plants are both male and female, but some plants are either male or female. Well that information is nowhere to be found at the garden center. But it would be a good thing to start to learn about if you have bad allergies. You can actually do something about this.
Plants that are illegal or subversive in some way-- I did include every plant that is illegal to grow in the United States, meaning not like a noxious weed or something like that. I mean like if you're growing them in your basement under grow lights, the feds are going to come knock on the door, that kind of illegal. Those are all in there.
But there are so many plants that aren't against the law, and that's what always astonished me. Salvia divinorum is one of them. It's a hallucinogen. It's a little kind of tender Salvia from Mexico. And if you guys don't know about Salvia divinorum, your teenagers do, I promise you. It's so much easier to get information on the internet about what will make you high than it was when I was a teenager.
So this is very easy to get. I got these plants on eBay. You can get a lot of interesting plants on eBay. It's not against the law to have, although states are starting to outlaw it one by one and the DEA has it on its list of plants of concern. I don't know if you knew the DEA has such a list, but they do.
One of the more infuriating things for me as sort of a plant person about this is that you'll see these news stories, local news stories. Salvia could be killing your children, news at 10:00. And I'm always like, say this species, say the species. Don't just say Salvia, that's awful. So I just want to emphasize, it's only Salvia divinorum. Every other Salvia in the world is wonderful and should be cherished and loved. This is the only one that will get your kids high.
That's what it looks like when it's in bloom. So it looks like kind of-- and by the way, you will never buy this plant by accident. This is not available at garden centers. You sort of have to know where to go to get one of these.
Does anybody want to guess, as we wrap up, what the world's most wicked plant is in terms of the number of people it has killed, total body count?
AUDIENCE: Opium poppy.
AMY STEWART: Opium poppy, that's interesting. What else?
AUDIENCE: Tobacco.
AMY STEWART: Tobacco, yes, 90 million people dead. Tobacco, most wicked plant in the world.
I was in Kentucky and I'm driving past these fields of tobacco. I always get very excited when I see my little wicked plants in person. So I said, "Stop the car, stop the car. I want to go." And I go running into some guy's tobacco field. And I want my picture taken with the plant. And it's taking this guy kind of a long time to figure out how to use my camera. It's sort of a hot day and I'm out there with my arms around the tobacco plants like we're at a high school reunion, and for kind of a while.
And by the time I get back in the car, I can't feel my hands. And my heart is racing and I am dizzy. And I realized, I just had two giant nicotine patches on my body. That may not have been the smartest move.
Tobacco plants produce this poison called nicotine. Nicotine is a very effective bug killer. That's why they make it. It's a very good insecticide. In fact, you used to be able to buy bottles of bug killer that had, as their active ingredient, nicotine. And they were taken off the shelf because they're so dangerous that we can't possibly have them in our homes. There's a gap in logic there that I don't quite understand.
But the point is, it's very good at killing bugs. That's why they make it. Of course for a lot of these poisons it's a defense mechanism. The plants are trying to protect themselves and they create some poison that does that.
Tobacco is also, of course, to blame for bringing slavery to the United States. The colonists needed something they could grow quickly for cash to send back to Europe to make a little money. And tobacco turned out to be that thing. And it was the need for labor in the tobacco fields that really fueled the early slave traders in the colonies. So a perfectly despicable plant in more ways than one as far as I'm concerned.
Now I just want to finish up by showing you a few pictures of my poison garden. I started growing these plants-- it's really hard for me to write about a plant that I've never seen or that I haven't grown. So any time I could get my hands on one of these plants, I would grow.
Now I live in Humboldt County, so there are quite a few wicked plants that are very easy to obtain in Humboldt County. But I really kind of searched far and wide, things like mandrake. You can't really just walk into a garden center and ask for mandrake. But I felt that would be very interesting to grow. And these plants eventually needed to go outside. They just weren't going to be happy under grow lights in my attic forever.
So I had this little sort of narrow side yard that's-- I have chickens in the backyard, so it's fenced off so the chickens can't get at them. And it's got a little fence in the front so the little neighborhood children won't be overly tempted to come in and sample the goods.
And I thought it would be fun rather than having plant markers to make tombstones and to say what the plan does rather than what it is. So I got those little kits at the craft store that you can make stepping stones for your garden. Well you can make tombstones with those too as it turns out.
[LAUGHTER]
So kidney failure-- so this is lilies, lilies for kidney failure. Madness for Datura. I had a whole little section of nightshades and Daturas that make you go crazy. Chemical warfare for hellebore. The Greeks used hellebore to poison their enemies' water supply. So it was like the first known instance of chemical warfare.
One of the great things about researching this book was going to the library and checking out books with titles like The History of Chemical Warfare. It was like, I wonder what my FBI file is starting to look like these days?
[LAUGHTER]
Lung cancer, of course. I had some nice Nicotiana in the garden. You can see it was a very pretty garden, and foxglove, Digitalis. I grew some nice ornamental tobaccos that were very lovely. So it really was a very pretty garden when it's in bloom.
[LAUGHTER]
So I had this idea that it should be a writer's garden because it was so connected to this book I was writing. So I started putting office furniture out there like a chair and a lamp and a bookcase and a desk, and of course having plants grow out of them.
And there's this company that makes skeletons for medical schools, resin skeletons. And they sell their factory seconds on eBay.
[LAUGHTER] And
Yeah. They will sell you what's called a bag-o-bones. And it's just assorted factory seconds. You're guaranteed at least one skull and a couple of hands and then assorted vertebrae and ribs and femurs and whatever else.
[LAUGHTER]
So I actually have these bones kind of in the garden like there's been a body buried there and it's starting to come up to the surface.
And the thing with the book is, so my husband and I own an antiquarian bookstore. And any time you're dealing in used books, you get a lot of books that are damaged and can't possibly be sold. They're mildewy. They've been written in. They've been torn out, something like that, and they're just going to have to go to the recycling bin.
And I had heard about this woman who buries books. And that's her art. She's an artist. And her art form is that she buries books in the ground or leaves them at the base of trees in the forest for like a year. And then she goes and retrieves them, digs them up, and exhibits them with whatever is living in them or growing out of them. And that's her art form. And I thought, well that's kind of cool. What would happen if you buried a murder mystery in a poison garden? What would happen there?
So I start pulling out from our recycling bin anything with murder in the title or just anything with a spooky title and burying them in the garden, some with the spines coming out. One book-- I swear this is a true story. One book, I didn't know anything about the book, but I liked the title. It was like Angel of Darkness or something. I thought, oh, that's good. And I decided to bury that one open. I thought that would be interesting to have it kind of coming up out of the ground as this open book. And I put it where the foxgloves are, the Digitalis.
And so I'm on my hands and knees and I'm burying the book and I'm sort of digging around and getting it at the right level and sort of reading it as I do that. You know how you read the back of the cereal box at breakfast? So I'm kind of reading it as I go. And I had opened the book randomly to a page in which a woman is accused of murdering someone with Digitalis.
[LAUGHTER]
I mean, I freaked myself out. I was like, I have to get out of here. This is going too far. This is too much.
This is actually an old botany book that was all moldy and mildewy. And the cool thing is that when the wind blows, the pages turn all by themselves. So it's very spooky.
So I think I'm going to stop here and take some questions. And I know I'll forget this, which is why I put it here. If you ever want to get in touch with me, there's the blog, there's the email list, there's Facebook, there's Twitter. It's everywhere. So you can go to website. And I'm also part of a speaker's bureau called Great Garden Speakers. And you can go online and post an audience review of a speaker you've seen. So that's just a little hint for you.
[LAUGHTER]
I'd appreciate that. But does anybody have a-- do we have time for some questions? Does anybody have a question or a comment before we finish up? Anyone? Anyone? Yes?
AUDIENCE: In your research, did you come across a tree from the Australian rainforest that when you eat the fruit, it kills you like 15 years later?
AMY STEWART: Oh, that would be good. I wonder, how would you know that it's-- do you know this to be a fact or--
AUDIENCE: No.
AMY STEWART: You just hope that it's true.
[LAUGHTER]
I hope that it's true too. There is a little desert shrub in the book that paralyzes you the next day. And I always thought that would be such a great plot for a murder mystery. I don't know, the killer almost escapes but then at the last minute the paralysis kicks in at the critical moment in the plot. Yes?
AUDIENCE: Have you ever looked in some of the jewelry that they have now with things rosemary pea beads and things like that? I've seen these things and then wonder, oh my gosh, people don't have that.
AMY STEWART: You're very smart to know it. Not everyone knows this. Yeah, Abrus precatorius, rosary pea, beautiful-- and it's in the book-- beautiful little bright red and black seeds. They look like little ladybugs. They're just wonderful. And they contain abrin. And it would only take a few of them chewed well to kill you. You do need to pierce that seed coat, however. So a great way to pierce the seed coat is to stick a needle through it and string them on a string and sell them as beads, right?
And I had heard that this happened, but I never could find them. One night I'm at a dinner with some people, like we were tonight, and this woman has several strands of it, of Abrus precatorius around her neck. And I said in my usual very diplomatic way that I am with complete strangers, I said, "You know, you have enough poison around your neck to kill everybody in this restaurant tonight."
[LAUGHTER]
She was like, "What?" I said, "Can I have that?" And she was like, "No!" She was horrified. No man, that stuff is out there. I mean I look at bead stores at seeds and it's like, yeah, seeds of what exactly?
I did actually see them in a jewelry store once after that. And they had this little thing about, these come from Peru and they represent good luck.
[LAUGHTER]
Good luck for who?
[LAUGHTER]
What is that? What else? Does anybody-- yeah?
AUDIENCE: Several years ago I went back to the house I grew up in in [INAUDIBLE]. And there in the backyard-- [INAUDIBLE] house when my grandfather gave [INAUDIBLE]. But I see by the fence, by the back door [INAUDIBLE] nightshade. So I said to the woman-- I think she was a grandmother. I said, "Do you know that that's poisonous?" She said, "Yeah, a four-year-old ate one leaf and was in a coma for four days.
AMY STEWART: Oh, did you all hear that, a four-year-old eating one leaf of energy--
AUDIENCE: [INAUDIBLE]
AMY STEWART: Yeah. Well, and you know, poison's in plants vary widely it should be pointed out. I will occasionally have people come up to me and say, well, I've eaten hemlock leaves and it didn't kill me. And it's like, I am so glad to hear that.
But plants can move poison around. Hemlock is a great example of that. They transfer the poison. It's pretty concentrated in the young leaves, but then they transfer it up into the seeds as the plant matures so there's less of it in the leaves. And even the time of day and the temperature and all kinds of things can influence the levels of poison. So whether it's one leaf or of you have to eat a whole bunch of it, can be highly variable even within one plant. What else. Yes? Go ahead.
AUDIENCE: I'm going to ask you about rhubarb and the fact that the leaves are poisonous I understand. Is that right?
AMY STEWART: The leaves of rhubarb are poisonous and the stalk is not.
AUDIENCE: [INAUDIBLE] obviously isn't. How far down into the stem--
[LAUGHTER]
AMY STEWART: Oh, how far into the rib from the sides? I don't know that we have any real data on that. And with rhubarb too, again, it's these calcium oxalates that are-- it's oxalic acid that's very poisonous in rhubarb leaves. And I have a general sense, without knowing this particularly, that by the time you've trimmed it down to the rib and boiled it and canned it and down all the things you're going to do with it that you've pretty much eliminated any possible risk from it. I actually think that more often than we realize we get little mild cases of plant poisonings and don't quite know that that's what gave us our upset stomach.
Hydrangeas have a little bit of cyanide-- like not a lot of cyanide, but a little bit of cyanide. And I always see them in bakeries as cake toppers. Like at weddings you'll see a big hydrangea [INAUDIBLE].
[LAUGHTER]
I just don't know how much cyanide I want in my wedding cake, maybe none at all. Yes?
AUDIENCE: Once of the things I've heard said, talking points for parents to their kids about drugs is to say to them, well, yeah, you turned out OK even though you smoked marijuana. But tell them that now it's so much stronger, the plant's been refined and marijuana today is 10 times more powerful than it was 20 years ago. True, false, [INAUDIBLE]?
AMY STEWART: Is marijuana is stronger today than it was? Yeah, actually yeah, because what happened is we started growing it indoors. It's so interesting to me. I mean I live in the middle of marijuana country in Humboldt County. I do. I mean, there's grow houses all around me. I own a bookstore and people come in and pay cash. And at certain times of year, the money smells like pot, the cash drawer.
So I'm right there in the middle of all that stuff. And it's fascinating to me the way these indoor hydroponic growers have taken bits and pieces of very interesting, high-end horticultural technology, green-house technology, and sort of adapted it to their uses, and combined that with sheer nonsense, and put all that together to come up with ways of growing these plants.
But yes, they've been breeding them. The strains have higher levels of THC and the growing methods are designed to produce higher levels. So yes, in fact that's true.
What they will say-- let me tell you what a Humboldt County pot grower would say. They would say, so what? It's the difference between drinking a beer and drinking a glass of scotch. Big deal, the proof changed. I don't know. I'm just telling you what they'd say. Yes?
AUDIENCE: When I was a kid I saw a movie on TV. I think it was an old classic [? or something. ?] And it might be the Wind Through the Everglades, or I could be confusing that with something else. But the scene that I remember is someone being tortured or killed by being tied to a tree and the bark, or making a slash in the bark. Does that sound familiar?
AMY STEWART: Yes, there are some wonderful-- I love that kind of stuff. There's actually an old opera with sort of that plot line, a tree that weeps poison and you just stand under it and perish. And there's actually an opera in which someone is so heartbroken that they just throw themselves under this tree and allow its poisonous vapors to consume them. So that's sort of a wonderful idea, but it does not appear to be actually true.
Well I think we're going to wrap it up. I'm going to go outside and sign books. So if anybody has any more questions or comments, please stick around. I would love to talk to you. Thank you so much.
[APPLAUSE]
In her New York Times bestseller Wicked Plants: The Weed That Killed Lincoln's Mother and Other Botanical Atrocities , Amy Stewart takes on Mother Nature's most appalling creations. It's an A to Z of plants that kill, maim, intoxicate, and otherwise offend.
Drawing on history, medicine, science, and legend, Stewart presents tales of bloodcurdling botany that will entertain, alarm, and enlighten even the most intrepid gardeners and nature lovers. Find out which plant killed Abraham Lincoln's mother, which shrub ignited a global war, and what plant has killed 90 million people. From strychnine to castor bean, from poison sumac to monkshood, from carnivorous plants to weeds that spontaneously combust, Stewart introduces an unforgettable cast of characters and tells their tales with her own wicked sense of humor.
This was part of the Cornell Plantations 2010 Fall Lecture Series.
