Friday, July 24, 2015

Poisonwoods and Death-Apples

& is used with permission.
Pop quiz: How many "poison" plants are there? And by that I don't mean plants which are poisonous; I mean the ones which cause contact dermatitis after touching them?

Answer: More than you think.

Last week I talked about good survival television and mentioned Naked and Afraid. One of the reasons I specifically added that show to my article is because it brought to my attention the existence of several poisonwood species of which I was previously ignorant. Everyone knows about poison ivy, and most of us who've been to summer camp or been in the Boy/Girl Scouts know about poison oak and poison sumac. But there are other, lesser-known species that are no less dangerous  and some are much more so.

First, the Classics
Special thanks to for these amazing maps and references. Be sure to follow the links below for more information, including lots of detailed color photographs of the plant in various seasons and environments. 

Poison Ivy
Eastern poison ivy and its Western sister species grows everywhere within the continental United States with the exception of California. It covers nearly all of North America, going as far north as the Canadian territories and as far south as the mountains of Mexico. Note that there are many states where both kinds exist!

Poison ivy likes to grow near water, such as rivers and lakes. Eastern ivy can appear as a vine or a ground plant; western ivy is ground-only. Both are equally nasty.
Poison Oak
Just in case you thought California was getting off lightly with not having poison ivy, let me introduce you to Pacific poison oak, which looks like it was specifically designed to bedevil Californians -- it's found all over the state, in all plant configurations, and when it burns in the state's frequent fires, the irritant inside it (urushiol, found in all of the species on this page) is aerosolized, meaning that breathing the smoke can result in harmful, sometimes even fatal, cases of rash on the inside of the lungs.

Oh, but don't be too smug, East Coasters: there's also Atlantic poison oak.

Poison Sumac
The good news about poison sumac is that it doesn't exist across the entire country like the others do. The bad news is that it's much harder to detect, as it doesn't follow the "Leaves of Three" rule. It simply has an odd number of leaves, between 7 and 13, on its branches.

It also looks like a shrub or small tree -- not a vine -- and so it's harder to detect and easier to bump into. The best way to avoid it to stay away from bogs, marshes, swamps and other wetlands where it prefers to live.

And Now, the Exotics
From the above illustrations, you can see that Florida, where I live, gets all three.

Well... five, actually. 

Also known as the Florida poisontree or hog gum, the Poisonwood is a flowering tree in the same family as poison ivy, oak and sumac. It can be found in south Florida (it grows abundantly in the Keys), the Bahamas, and all the way through the Caribbean. Its sister species, the chechem or black poisonwood, is found further south in Cuba, Jamaica, the Dominican Republic, and from southern Mexico (Yucatan to Veracruz) to northern Central America.
Poisonwoods are nasty customers. They are infused with urishiol in greater concentrations than ivy, oak, or sumac; it's practically acidic in the way it burns. In at least one instance, poisonwood sap resulted in a second-degree burn. Watch this video to see how quickly it starts affecting someone who's touched it.

Its bark looks like it is oozing sap, or has a skin disease.
For more information on how to identify the tree, visit the University of Florida School of Forest Resources & Conservation, because if you go on vacation in South Florida or the Caribbean, you WILL want to know how to identify it.

As bad as the poisonwood is, though, there's actually another tree in Florida that's much, much worse. How much worse?  The Spanish name for it has the word "death" in it.

The Manchineel, also known as la manzanilla de la muerte -- "little apple of death" -- will not only burn and blister your skin if you touch it, or you stand beneath it when it rains, its sap (or smoke from burning it) can also cause blindness and eating its apple-like fruits can kill you.
The caption for the above picture literally states  All portions of the manchineel tree are poisonous. It actually holds the Guinness World Record for "Most Dangerous Tree"! (I didn't even know there was a contest!)

Here's a first-account account of someone who ate a manchineel fruit -- a "beach apple" -- and lived to tell the tale.

Manchineel trees can be found throughout South Florida, the Bahamas, the Caribbean, Central American, and northern South America.

If you plan on going on vacation to one of those places, then learn to identify it. Not every tree will be as obligingly labeled as the one to the right.

Side Note
There's actually a sixth poison tree, the Chinese lacquer tree, which is the same genus as poison ivy, oak, and sumac. But it only grows in China, Korea, Japan, and parts of the Indian subcontinent. But as this article is already excessively long and not many of my readers will encounter one, I leave its investigation as an exercise for the curious student.


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