Do not eat, touch, or inhale the air around the manchineel tree! You could die.

Throughout the coasts of the Caribbean, Central America, the northern edges of South America, but also in south Florida, there can be found a pleasant-looking beachy sort of tree, often laden with small greenish-yellow pretty fruits.
You might be tempted to eat the inviting fruit. But no, do not eat the fruit! Or maybe you might want to rest your hand on the trunk, or touch a branch? Absolutely no, do not touch the tree trunk or any branches! But also…do not stand under or even near the tree for any length of time whatsoever, do not touch your eyes while near the tree, do not pick up any of the beautiful shiny, tropic-green leaves. If you want to slowly back away from this tree, yes. Do it.
After all, it is rumored to have killed the famed explorer, Juan Ponce de Leon.
This is the manchineel, known sometimes confidentially as the beach apple, or more accurately in Spanish-speaking countries as la manzanilla de la muerte, which translates to “the little apple of death”.

If I say that all parts of manchineel are extremely poisonous, and any interaction with and ingestion of any part may be lethal, believe me, it is not an exaggeration. Its fruits, though described as sweet and tasty, are deliciously toxic. Shipwrecked sailors have been reported to have eaten manchineel fruits and, rather than dying a violent death, they had inflammations and blistering around the mouth while other people have been diagnosed with severe stomach and intestinal issues.
Also the sap, white and milky, is spectacularly toxic and it causes burn-like blisters upon any contact with skin. If you’re unfortunate enough to get it in your eyes, temporary blindness is highly likely, and the sap is found throughout the tree, including in the bark and leaves, so please, don’t touch any of it.
Despite the specific toxins found in the sap and in the fruits remain partially unknown, are not unused: the aboriginal peoples of the Caribbean were familiar with the tree and used it for many purposes and the sap, in particular, was used to tip arrows. The same that killed the same Juan Ponce de Leon, apparently.

Scientifically, Manchineel is a member of a family of plants known as the spurges, and the name comes from “purge,” because, although all these plants have toxic sap, the toxicity varies, and some can be used as a laxative.
Spurges are found worldwide, in various forms, ranging from tiny herb-like plants to large bushes and trees. Manchineel is one of the largest, reaching up to 15 meters in height but, interestingly, it is not the most famous. That’d be the poinsettia.
The manchineel tends to live along the coast, especially in brackish water. Assuming you want to find one for some reason, it’s most common in the Flamingo section of Everglades National Park, along with some smaller Floridian islands like Elliott Key and Key Largo.
The manchineel fruit are completely toxic, also for animals. Its scientific name is Hippomane mancinella, which translates to “little apple that makes horses mad,” showing that we’re not the only species to find the fruit problematic. However, the Floridian manchineels look not to animals but to the seas for help spreading seeds. Fruit drops from the tree into nearby water, and thanks to its buoyancy, is taken by the tides somewhere else. Eventually the fruit rots and the seeds can grow. Strange enough, but this isn’t an uncommon method of seed dispersal, also being used by more common plants as the coconut palm.

In any case, though the manchineel is the deadliest tree in the country, apparently it’s not the deadliest plant. There are other plants in Florida that are far more toxic than manchineel, for istance spotted water hemlock (Cicuta maculata). It is said that a quarter-inch of the stem is enough to kill a person. And of course, it’s also found in Florida, probably America’s weirdest, most fascinating, and, apparently, most dangerous ecosystem.