10 Plants to Die For. Literally.
Not sure if Michael Jackson thought of these plants while coming up with Dangerous, but it's a well known fact that even harmless-looking organisms like plants can be mean and hostile. Ten of them seem share-about worthy, because they stand out with their extreme defensive mechanisms, that you will see sometimes apply to humans only. Which is kind of insulting.
#1 Deadly Nightshade
I guess by the female super villain name you have already concluded this plant is evil. And you're right! It is highly poisonous from the bottom to the top(berries AND foliage). No wonder people have been poisoning each other(on purpose) with it for many, many years in the past. Nowadays you just go and pull the trigger, not a biggie. Back then it was art to murder someone. Especially if that's Emperor Augustus(who is rumoured to have been poisoned by his own wife, which I am not going to say anything passive aggressive about in relation to women behavior). In ancient times archers used it to make poison arrows as well. But hey, here's a fun fact - familiar vegetables and fruits such as tomatoes, potatoes and eggplants are part of the same family(nightshade). So it's not a surprise they all have toxins present in their foliage as well. So tomato leaves' salad is out of the menu for tonight, I'm assuming.
You have probably seen this evergreen shrub growing freely here and there. It's very widely spread despite the fact it is extremely toxic. Statistically speaking it is one of the most common grown toxic plants. Which is weird because evidently even smoke from burning Oleander could be deadly. Which is weirder because you can encounter it in schools even. And as we know schoolboys tend to go around and light stuff up. But this pretty lady has a positive side as well. The American Cancer Society has found out that the plant potentially has benefits in cancer treatment, although it requires intensely weakened arrangements. You could consider Oleander the anti-hero in your book.
Sometimes recognized under the name Daffodil, this is, again, a widespread participant in our surroundings, famous for its aesthetics. But did you know it contains lycorine? Did you know what lycorine is, even? It's a poisonous alkaloid which can be found in the bulbs of the plant and in smaller portions in the leaves. Apparently this has been known for a while now and even some suicidal attempts have been done. But even if not aiming to kill yourself(which, by the way, in case you are, will result in a very unpleasant death) occasional unintentional poisoning has been reported due to the fact that the Narcissus bulbs very much resemble the ones of the onion and leeks. Death is rare though, since you have to consume large quantities of them and they have a very specific undesirable flavour. Moral of the story: find better ways to suicide.
#4 Doll's eye(white baneberry)
A good example of weird looking stuff nature produces. This thing looks like the kind of herb witches put in the Grow-me-some-legs-because-I-am-half-fish-half-human potion. But this is not a creepy looking plants list. The berries(eye looking thingies) of this plant contain toxin that can immediately affect your heart and result in cardiac arrest or death even. But that's unless you are a bird. Birds remain unaffected of the plant's poison. Maybe because these plants prefer birds over humans for their main seeding aid. Let's just pretend that's not offensive.
#5 Stinging Tree(my personal favourite)
Now this baby right here is something. Aside from the fact that its poison is potent enough to kill pigs, humans and even horses, there's this scenario where you don't really die but suffer unimaginable pain. The agonizing ache even has stories on its own. Like the one where horses have been seen jumping off cliffs after being in contact with the plant, or another where some guy decided it would be better to shoot himself rather than bear with it. If this is not enough here are more fun facts - the pain may stay as long as weeks, or even months. This is the kind of plant you slap Hitler in the face with. But again there are actually some species of mammals, birds and insects "allowed" to feast on it. This is starting to sound more and more like a plants' anti-human conspiracy theory(Bonus offtopic: see "The Happening" from M. Night Shyamalan)
#6 Angel's trumpet
This plant is respected for its aesthetic appearance and it is being grown occasionally in gardens. But despite its undisputed beauty this plant can be nasty. As in really awfully nasty. For a start - all of it is poisonous if ingested. No exceptions. It contains high dosage of hyoscyamine, scopolamine (also known as hyoscine), and a few others of the like. Which are basically a bunch of toxins you are highly unlikely to enjoy. Of course, the consequences of ingesting it could be migraine headaches, paralysis, as always - death, mydriasis, tachycardia, rapid onset cycloplegia and other unpleasant sounding medical conditions. But its charm comes from the fact it induces hallucinations. And the cool part is you will always hate what you see/hear to the point that it might lead you to temporary insanity. It is well known that the consumer will experience a complete disconnection from reality and will not be aware he is actually hallucinating. There's even this guy who apparently decided he will be better off without his tongue and penis after a small dose of the plant's tea. Moral of the story: if you value the blessing of having a pee pee - keep away from having Angel's Trumpet tea parties.
It is no secret this plant would also be poisonous if included here. There are the boring facts of how in ancient times meanies used it to poison their foes' drinks, death occurs instantly if large enough dose and all that. But let's discuss the fascinating side of its toxicity. So the plant has aconitine present in it. And it is apparently soaking with the toxin since even a slight touch could poison you, because it is easily absorbed through a person's skin. Eventually after making the silly mistake to come in contact with it without wearing protective gear(according to professional gardeners wearing gloves is a must, although poisoning does not always occur) you will start feeling this very typical for the poisoning tingling and numbness. It will then unfortunately proceed upwards to your shoulder and then aim at the heart. It is rather troublesome that the treatment of the poisoning would be only being monitored. Conclusion: poisoning is bad for you.
#8 Rosary pea
This plant, also popular under the the name Crab Eyes, for obvious reasons, is responsible for jewelry being a highly bad-ass occupation. This sentence will make sense, I promise. The peas of the plant are arbin rich, which I'm assuming you're not familiar with(it's poison stuff), are used as ornamental decoration. The thing is that you can accidentally prick your finger while crafting this rather ugly piece and even more accidentally die. I mean gloves and finger protectors are for weaklings right, real men do their jewelry barehanded. But do you think such sacrifice is worth a crab eye-looking necklace? Moral of the story: buy real jewelries and demote rosary pea marketing.
#9 Apple seeds and Cherry seeds
Both apple seeds and cherry seeds are toxic thanks to cyanide with the difference that the latter contain a substance that will lead to releasing cyanide in your body if ingested and the first ones contain it, just like this. The fruits on the other side contain vitamins and antioxidants that are healthy for you. So what do you do? Well, what you always have, since obviously you haven't died from apple seed poisoning yet. Swallowing 1-2 seeds won't do harm but you should be rather cautious with the cherry seeds because it has been reported that consuming too much of them leads to vomiting, dizziness and even death! Now just imagine how someone highly intelligent with a lot of potential to succeed in life dies from consuming too much cherry seeds, because he/she was too lazy to spit them out. Ludicrous right?
#10 Hemlock (or plant that happened to kill Socrates and a bunch of other people)
And speaking of highly intelligent people being poisoned by plants here's a good example. Hemlock is a poisonous plant that contains another toxin you haven't heard about called coniine. You also have no idea how to pronounce that. And neither do I. Anyway, it's similar to nicotine in chemical structure and it makes you die. Ask Socrates. Oh, wait. The effect of the poison includes a progressive paralysis that slowly overtakes your body and eventually kills you. Your muscles ache as they die along the way too. It takes the toxin up to several hours to murder you but only 30 minutes for the symptoms to kick in.
Bonus fun fact about Hemlock: According to Plato's description of Socrates' death, his last words were very philosopher-quality: "Crito, we owe a cock to Asclepius. Pay it and do not neglect it."
Bonus fun fact about Hemlock 2: The funny looking Quail birds feed on hemlock seeds, because they can afford it. These little guys are immune to the poison of the plant. But that was not the fun fact. If you have the misfortune to eat quail that has recently consumed hemlock seeds you will definitely get paralysed. It's a good plot story for your new crime novel.