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Do Not Eat, Touch, or Even Inhale the Air Around the Manchineel Tree (atlasobscura.com)
327 points by kposehn on Dec 22, 2016 | hide | past | web | favorite | 130 comments

I thought the mention of water hemlock near the end was interesting. Actually, common poison hemlock (which is related) grows all over the U.S. midwest like a weed and it is very deadly. You will see it growing in fields and at the side of many highways if you drive through Ohio. It is commonly mistaken for wild carrots (aka queen anne's lace). It famously was used to poison Socrates, and it kills a lot of livestock accidentally in modern times.


I didn't realize that was hemlock. We have it growing in our back yard in a bad patch of weeds we need to clear out.

I've actually cleared it out before and didn't even realize what it was. I volunteer to clean up invasive species, and we end up pulling a lot out when we clean up buckthorn along with garlic mustard. I probably knew it was hemlock at one point it time, but it didn't really stick.

It looks very similar to lots of other plants, some of which are edible like fennel.

This plant is all over California. I am actually surprised I have never heard of any fatalities.

In my experience, modern Americans rarely go around eating weeds from the wilderness / side of highway. Lack of fatalities is not surprising.

I recently picked a bunch of wild fennel seeds while out on a hike, then got home and realized that the plant is pretty hard to tell from poison hemlock when dried out, and that perhaps I might have managed to mix in a few hemlock seeds... :-/

The article by the radiologist who ate the fruit of the manchineel came up here some weeks ago.

Can't believe anyone would consider eating random fruit let alone a radiologist. You must be pretty smart to become a radiologist right?

This quote may be a clue to how it happened:

> Sadly, the pain was exacerbated by most alcoholic beverages

I guess alcohol effects people differently. I'm certainly a bit slow when I have too many beers. But I'd never consider just eating random things.

But the account of their ordeal seems to be fairly detailed. So they can't have been that drunk!?

The medical profession appears to reward skill in memorization over novel intelligence. The vast majority of doctors will never work with anything that hasn't been done thousands if not millions of times already. Often when they leave their field the dunning kruger effect takes hold and you have stuff like this happening. The uneducated farm boy won't eat the fruit because he doesn't know anything about it, the radiologist does because he thinks he knows.

> Often when they leave their field the dunning kruger effect takes hold and you have stuff like this happening.

For an excellent example of this, see ignorant comments about the medical field on Hacker News.

If only ad hominem's refuted claims. What a tender world that would be.

Don't really need to refute a claim with no evidence to support it written by someone likely not involved in the field.

People who are correct can come up with something better than an argumentum ad verecundiam.

Why should they? You throw out some nonsense claim and then it's on random internet folk to dive in and do the research to prove you wrong? Get over yourself.

I know many a toddler that will eat anything and everything that's within reach. Eating grass, weeds, bugs, or even dirt is not out of the question.

Science is increasingly siding with these toddlers (improves biota, reduces asthma); just not re this particular plant, of course.

there are 4 entries for my city.

these four entries are dumpsters.

what a fallen fruit, indeed.

There are a lot of entries for my city ... one is a dumpster and upon closer investigation it's behind a grocery store.

I just checked my town, Bellevue NE, a Suburb of Omaha, we have a garden and two Apple orchards. The middle of nowhere ain't so bad.

At the ER?

> I am actually surprised I have never heard of any fatalities.

There are loads of toxic flowers, plants, and trees.

As for your question. I guess because people generally don't live like Into The Wild [1].

[1] http://www.imdb.com/title/tt0758758/

If you live in central/north Europe, beware of Heracleum Mantegazzianum: https://en.wikipedia.org/wiki/Heracleum_mantegazzianum

When I was young, these grew in our neighborhood. I remember my parents giving me very stern warnings not to touch that plant. I found it strange that such a nasty plant was allowed to grow in a neighborhood with little kids around, but then again there's lots of nasty plants in German gardens.

After I made the mistake to touch a stinging nettle, I took such warnings more seriously.

To be fair, touching a stinging nettle is standard fare of childhood, and isn't really bad for you other than the pain. If you spend lots of time out and about in green spaces in certain parts of Europe, getting stung by some nettles will be unavoidable.

At least in Russia, it was almost a rite of passage to have "nettle-fights" - you and your friends all put on a pair of gloves and some shorts, everyone grabs a nice nettle, and then you start whipping each other with them.

Yeah I ran into one of those as a kid. Thankfully it was a rainy and cloudy day so didn't get any scars from the burns (it reacts with sun light)

Also getting rid of those things is pain in the ass as the seeds can remain in ground for up to 10 years before the plant starts to grow

We have to watch out for that in the US too, as well as wild parsnip.

For more information on the mighty Hogweed please consult this handy PSA featuring Peter Gabriel and Phil Collins.


I have heard that this plant is very difficult and dangerous to destroy.

Western Europe, too. It's pretty common in the Netherlands.

Every spring I google "poison ivy" so I can remember exactly what it looks like. And every summer, I get a poison ivy rash.

Now that I know this tree exists, I have little doubt I'd die after a hike in the Caribbean.

> Now that I know this tree exists, I have little doubt I'd die after a hike in the Caribbean.

It's really not that big a deal. On most islands they are clearly marked with a red band. Don't touch them, don't eat strange fruit off the ground, and don't stand under them in the rain and you'll be fine. Even if not marked, just don't go groping trees. Don't worry about breathing the air, that part is sensationalist bullshit.

What's more dangerous, as tour guides will be happy to tell you, are coconut palms: Falling coconuts are responsible for more deaths per year than shark attacks. (Although that says more about the rarity of shark attacks, I guess...)

Oh well, atlasobscura seems to need the clicks.

> atlasobscura seems to need the clicks.

And then there is this: "After all, it is rumored to have killed the famed explorer, Juan Ponce de Leon." By which they actually mean, a few paragraphs later, that the arrows that killed him "may have been" tipped with it. (If it had just been the arrows and not the irritating sap, surely he'd still be with us today.)

I've seen a few atlasobscura links on HN, usually I already know what the topic will be from the headline. Something feels a bit off about the site, almost like they exist for no purpose but to generate traffic.

Correct. The Galapagos have many of these trees and all are marked on paths.

The article did not mention it, but the poison severity of the tree varies quite a bit with season. Once the fruit has all fallen, the milky irritant on the tree has dried or washed off. You should still avoid staying under them in the rain as mentioned above.

Have you tried not googling "poison ivy" in the spring?

What you don't know, can't kill you! Or so they say :)

The last time I said that I was told I will live a long life. I've never repeated this phrase since.

Even better, try not being sensitive to urushiol.

Here's a handy video that can help you stay rash free next summer https://www.youtube.com/watch?v=4oyoDRHpQK0

Basic idea is that you need to clean yourself with a washcloth or loofah. The oil from the plant is like automotive grease. You need to scrub it off.

IDK about poison ivy, but for automotive grease, Dawn Ultra works wonders even without a scrub.

Like my dad says, "you haven't been proper dirty till you've had to use Dawn as shampoo".

Brake dust, OTOH, now there you need to scrub, preferrably with a stiff nail brush.

Yes soap will get rid of Urushiol and some mechanical action is required, HOWEVER the last thing you want to do is weaken the skin and break it down with too vigorous a scrubbing. That will just facilitate penetration of the oil into the skin, and make you more vulnerable until your skin has repaired.

I get exposure to poison ivy on a regular basis but I know there's a 2h grace period in which I do all the yardwork around that stuff then jump in the shower. A normal shower takes care of it all.

I wrote this in another branch, but I should repeat it here: I've had total success by cleaning with naphtha soap after contact with poison ivy.

Googled Poison Ivy - seems I'm in a different search bubble.

After having a bad run-in with poison ivy as a kid, I can't unsee the plant wherever I go. It's practically neon in my mind. It's amazing how the brain works.

Same here. Now I only get it in the winter when the leaves are down.

As a kid I was always annoyed that nobody could give me a concrete description of poison ivy. The leaves are shiny! There are three! Beyond that everything got really vague.

Imagine my surprise a few years ago when I googled and discovered that Poison Ivy isn't a plant, it is a whole family of plants with quite a bit if variation in the family.

One thing to watch out for is root runners on the sides of trees. Some varieties climb trees for more light and the only part you see is the fuzzy brown roots--which are just as irritating as the leaves if you touch them.

Perhaps off-topic, but I stopped having problems with poison ivy once I started cleaning my skin with naptha soap after any suspected contact.

I'm fairly certain any soap will do as long as you wash off the affected area within a couple of hours of exposure

You should visit this place: https://www.youtube.com/watch?v=tboW11dMeKs


Definitely thought this was going to be https://xkcd.com/443/

I read somewhere that, if you get stranded somewhere and your last option is to eat some natural plants/fruits that you don't know, the rule was to take a small bite and wait for few hours. Most poisonous things would not kill you this way but will give you a hard time so you know it's not safe. Otherwise it's safe-ish to eat

I learned a similar but more cautious method in a jungle survival school:

Step 1: Touch the plant with your hand, wait 1 hour for negative effects to develop.

Step 2: If step 1 produces no negative effect, touch the plant to more sensitive skin, such as the inside of your forearm. Wait another hour for negative effects to develop.

Step 3: If step 2 produces no negative effect, touch the plant to the area around your mouth. Wait another hour.

Step 4: After touching your mouth with the unknown plant and seeing no ill effects, chew up a tiny bite of the plant in your mouth and spit it out, and then wait another hour.

Step 5: Ingest a tiny amount of the plant and wait an hour for negative effect.

Step 6: If no ill effects are felt at this point, the plant is likely safe for you to eat.

This is a very long and difficult process, but it's the safest way to determine if the plant will kill you. If you see a lot of one type of plant that you think you might be able to eat, it's worth the wait to figure out if it's poisonous or not. Once you've identified an edible plant, you can continue eating it without going through this process again.

Another general rule is that milky sap typically is poisonous, and you should definitely avoid fruit that has milky sap. And of course, if it tastes bad, that's probably a good sign that it might not be edible either.

Thank you, that's a good piece of advice that I remember hearing as well.

I'd wait a lot longer than an hour after sampling a little. Many poisonous foods take a lot longer than that to take effect. I'd wait at least a day after tasting a little.

Also, often (always?) the poison's in the dose. A little might be safe to eat, more not so much. So I'd go really easy when eating something new.

I remember a more incremental approach:

1. Mash it and hold in the pit of your elbow for an hour. If no irritation, go to step 2.

2. Hold it in your mouth for an hour. If no irritation, go to step 3.

3. Eat a bite and wait a few hours. If no irritation, go to step 4.

4. Eat a small amount and wait a few hours. If no irritation, it's probably safe to eat.

Yep, that's a condensed version of the universal edibility test.

It's on page 103 in the FM 21-76 US ARMY SURVIVAL MANUAL: http://www.preppers.info/uploads/FM21-76_SurvivalManual.pdf

Step 1 reminded me of an amusing problem: - 16 bottles of wine, one has been poisoned.

- poison takes 1 hour to kill you, party is in 1 hour.

- you have 4 prisoners you don't mind sacrificing to find out which bottle is poisonous but obviously you'll need to do all your sampling now because otherwise you won't know which bottle not to use in time for the party.

EDIT:16 not 17 bottles of wine.

I feel like this is solvable using binary to assign which bottles to which prisoners, but only if there were 16 bottles. For example, bottle 11 dec = 1011 bin. So bottle 11 would be tasted by prisoners 1, 3, and 4. Then if 1, 3, and 4 die, we know bottle 11 is poisoned. Every combination of prisoner deaths would point to a unique bottle.

Except 17. Fencepost error on my part maybe?

No, you're correct I typo'd.

Actually it seems you can have a 17th bottle.

Use binary search to find the poisoned bottle among bottle 1 to 16. If you fail to find a poisoned bottle, it is the 17th

No, that's already covered by 0000, nobody drinks that one. Number the bottles 0 to 15 and it's clearer.

That riddle is sometimes called "criminal cupbearers".

Common presentation uses 1000, gives it away to use a power of two.

A really fun extension to it is to suppose that you use the same criteria (a thousand bottles, consumption of the smallest amount will kill, but after a delay that means you must perform a one-pass test) but _two_ bottles are poisoned. What is the minimum number of prisoners you need for your test to find the two poisoned bottles precisely and what is the procedure?

(This is _substantially_ harder.)

Only works if none of your prisoners are named Reed or Solomon.

Whilst this is a permutations problem, what parties need wine that much that you'd risk fatally poisoning people?

Not people, prisoners. The point is to not poison the actual people attending the party, yet still give them wine.

"Not people, prisoners."

I get that it's a game, but can't let this slip into the memesphere unchecked.

People are a superset of prisoners. Some of our largest problems as a society are a result of our not acting as such.

I think it's obvious from the setup of the puzzle that the prisoners lives are completely expendable without repercussion. That kind of precludes any of the more liberal/modern methods of handling prisoners and leans more towards medieval-style prisons.

I don't disagree with you on the obviousness of the set-up. I'm drawing attention to the more subtle language structure which, by design, defines prisoners as non-persons.

I quite like the mathematics of the puzzle, I also like justice and am aware that justice is a product of language in many instances, as many people interact with the world through language without giving much thought to it.

I don't think language states people aren't prisoners.

In fact, my statement was meant to ridicule the assumption that prisoners are worthless to point out they are people.

... and as second goal, becoming a prisoner in jail some time later, for the cheap prize of some bottles of wine.

This is the kind of problems that AI machines would try to solve, wrongly. Humans still score better understanding that some theoretical problems must not be solved.

Apparently you failed the scum detector. Good luck in your future encounters.

Hamming code.

"Reprinted as NOT permitted by U.S. Department of the Army, but by we the citizenry who paid for it"

Ah, preppers.

One exception to these rules.

It will pass all your tests without causing any irritation but still kills you in the end:

"There are no negative symptoms from eating this fungus until 6–24 hours after ingestion"


Unknown mushrooms though, should really be your very last recourse, only if there's really, really nothing else to eat at all where you are.

Many mushrooms are toxic when raw (even the ones used for food), so you should better stay with fruit and berries.

The rules are for plants :)

It might be good to wait a few hours to a day between each step.

Urushiol (Poison Ivy et al.) usually takes about 4-6 hours to start showing symptoms.

"This man died of starvation"

"But how is that possible? He's surrounded by fruit!"

The rule of thumb is that you can survive:

3 minutes without air

3 days without water

3 weeks without food

So you're probably not going to die without food if you go even for some days without it. In fact, many people regularly fast for days on end, some (such as people on hunger strikes) have fasted for weeks.

Of course, all of the above rules of thumb are subject to modifications based on things such as the amount of physical exertion you're under, your health, the weather, etc. If you're doing lots of exercise in the heat, you're going to need a lot more water than if you're lying still in the shade.

And apples at that!

> Otherwise is safe-ish to eat

Not necessarily. Plants aren't so stupid and there are poisons designed to catch you at the middle and long term. Peas have those for example.

Better studying a little botany instead. Euphorbiaceae is a wery widespread family, relatively easy to recognize by its very specialized flowers. All are very poisonous and you can't eat it, but some of them can still be handy. Can provide you wit car tires, torches, fuel, killing your enemies and treatments for diarrhea, expelling worms and, as a nice special bonus, remedy for genital herpes. Yeah, they know what a real survivor needs.

Aren't the main uses for plant poisons/toxins being a defense mechanism for the plant? What evolutionary advantage does killing a predator hours after they killed you have? Seems most "smart" plants would try to be as painful as possible up-front, before they get eaten.

It would wipe out threats to the species.

This would work for organisms like us, but plants are organisms structured following a clonal design; can explore other solutions not available to us. And they need also some animal services.

I personally am going to plan on never being in a situation where I have to eat random wild plants to survive.

Not many people plan to be stranded in a random island/forest. But if you do, it's better to be prepared.

> "The toxicity to humans, though, that’s a mystery. “There really isn’t an evolutionary answer to its being toxic, other than to just say it’s a biological mistake because it certainly doesn’t gain anything by being toxic to humans"

I am quite puzzled by this quote, in evolutionary terms, humans are very recent. I highly doubt that humans have been around for long enough for plants to evolve to suite humans specifically, rather than mammals in general.

Humans mean probably "a member of primates" in this context. A lot of fruit plants coevolved with primates but following the other direction. We are big diseminators of seeds and an interesting target to atract and spoil.

Fruits designed for dinosaurs-birds and fruits designed for mammals are often very different in its chemical composition.

Also, mistake implies that there is some agency and or design intent involved.

Corn has.

There is a big difference between evolution and selective breeding by humans.

We gave it some help.

I have been stung by stinging trees and it is not pleasant (Australian understatement).

Reminds me of the Devil Tree (Triplaris americana) found in South America[1]. Anything that touches its bark (bird, insect, human) is ferociously attacked by colonies of venom squirting red ants.

Learned about this fascinating tree in the equally fascinating book "1491" by Charles Mann[2].



Your comment makes me think that the Latin speaking world likes to attribute bad plants to the devil.

There's a drug that Colombians call the Devil's Breath[1]. Which is believed to be scopolamine[2], which had previously been used as truth-serum. The rumors go that the drug makes you "zombified" and compliant, willing to do whatever is suggested to you. It's my understanding that the drug is extracted from belladonna[3] though it's hard to know what is actually true about the rumors. Vice has a video about it[4], though I haven't had the opportunity to watch it yet.

[1] https://www.theguardian.com/society/shortcuts/2015/sep/02/de...

[2] https://en.wikipedia.org/wiki/Hyoscine

[3] https://en.wikipedia.org/wiki/Atropa_belladonna

[4] https://video.vice.com/en_us/video/worlds-scariest-drug-colo...

Here's the passage in the book where the "Devil's Tree" is encountered:


The quoted article by the radiologist was discussed recently: https://news.ycombinator.com/item?id=12257523

I wonder if the plant exhibits (or will eventually) the Edge Effect [1].

Poisonous plants such as poison ivy often do because people will avoid the plants but will tromp on others (thus the poison plants survive readily on the edge since there is less competition).

That being said if the plant is exceedingly a nuisance like mosquitos it might prefer not to live on the edge (as humans will actively destroy it).

[1]: https://en.wikipedia.org/wiki/Edge_effects

Someone with minor poisoning: https://www.youtube.com/watch?v=364GFrNa3wA

> Yeah I was thrashing around in pain, until I cracked a joke and felt emotionally better. That's why I picked up my camera and decided to chronicle my adventure. The thing about unbelievable pain is that sometimes it's so unbelievable that you can't believe it and there is some humor in that. For people like me anyway. 

Takes it pretty well, but it sure does look painful.

Ooohhhkeeey, "manzanilla de la muerte" slept under one during a hot afternoon in a nature reserve in ecuador. Great shadow at that point, had some red dots on my arm and back later... And yes, there were huge signs not to touch the tree and eat the fruites, but it was the only shadow around.

Could the poison fruit be to prevent fish from eating them while they float through the ocean?

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1127797/ is a recent report of tourists eating manchineel fruit.

It was linked to and directly quoted from in the article.

So apparently the wood from its similarly-toxic relative https://en.wikipedia.org/wiki/Metopium_brownei, "black poisonwood", is in use in things like musical instruments? http://www.bonedrymusic.com/Chechem-Rhythm-Bones-s/283.htm

Ironically, ‘Manchi neellu’ in Telugu language means, ‘fresh water’

I wonder if the fruit was eaten by an extinct (or locally extinct) animal. Any plausible candidates?


We ban accounts that post uncivilly, so please don't do this.

We'd appreciate it if you'd (re)-read the following, which give an idea of the kind of discussion we're hoping for here:



I did RTFA; it said iguanas are not native to the area. If they used to be, that'd be a good answer.

And this is a walnut tree: https://en.wikipedia.org/wiki/Juglans_regia

Compare the fruit, leaves, and bark.

Even if one couldn't tell the leaves apart, the bark of the trees is completely different. One is smooth, the other reddish. And of course there's no way you would mistake the brown-green husk of the walnut for manchineel fruit - they are smaller in size, the husk is often cracked near maturity.

Not that we don't have issues with walnuts, either..

It would help to link to some photographs, and make pronoun references unambiguous.

I've never seen a manchineel tree. Perhaps they do look quite different in real life. But based on the photographs I've seen (e.g. on http://psytreasure.com/little-apple-death-deadly-plant-used-...) there's a risk of confusing the two plants.

From what I can tell based on photographs (here walnut = Juglans regia):

Leaves: Individual leaves are very similar but walnut leaves have a pinnate arrangement, manchineel don't.

Fruit: If they're shaped like apples, or are yellowish, they're manchineel. However, manchineel are often more oval and coloured similarly to walnut (see photo on psytreasure page).

Bark: There's enough overlap here that I wouldn't rely on it.

Location: Manchineel trees are usually located on the coast or near water. Walnut trees can be found anywhere.

Range: Manchineel trees are located around the Caribbean Walnut is Eurasian, but has North American relatives (e.g. black walnut).

Advice: If you're near the Caribbean and see what looks like a walnut tree, avoid it.

More general advice: If you're not sure what a plant is, don't eat it.

> More general advice: If you're not sure what a plant is, don't eat it.


One has simple leaves, the other has compound leaves. And do the ranges even have much overlap?

There are differences if you know what to look for. I've often collected walnuts from trees in England and thought they looked similar. I don't need to check if the leaves are pinnate - they always are. If I hadn't been forewarned, I might have got as far as cutting the manchineel fruit open before discarding it, thinking it was a related species.

Lack of range overlap makes misidentification by someone from outside the range more likely.


Add this to the "Nature is Terrifying" list...

Sometimes nature fakes it.


Pretty harmless, but they've been known to drag away mice.

I'll make sure not to eat the air around this tree

IMO this title would be better if it were broken not to be so parallel:

"Do Not Eat, or Touch, or Even Inhale the Air Around the Manchineel Tree"

Chemical data is missing though.

Up next on Brave Wilderness...

Ironically, ‘Manchi neellu’ in Telugu language means, ‘fresh water

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