POISONWOOD

One tree around here anyone who works in the woods learns early is the Poisonwood, METOPIUM BROWNEI, in Maya known as Che Che'en. Its alternate, pinnately compound, wavy-margined leaves are shown below:

Being acquainted with this tree is important because if you get the tree's sap on your skin your skin may itch, develop a rash, and even break out in running, scar-leaving blisters. Poisonwood belongs to the Poison-Ivy or Cashew Family, the Anacardiaceae, so that explains a lot.

Besides its compound leaves, which are similar to those of ash trees up north, a good field mark to help in identification is that often the tree's trunk bears black, tar-like blotches, where sap has dried, shown below:

When Poisonwood sap first begins emerging from a wound on the tree it's clear. In about ten minutes it turns to a bright, rusty-red hue, then after 20 minutes it's black, and it stays black.

My impression is that Poisonwood sap causes much more than a mere allergic reaction. Most of my life I've experienced no symptoms at all when exposed to Poison Ivy, even its sap smeared on my skin (I seem to be losing some of that immunity now, however.) Still, my skin reacts to Poisonwood sap as if it were a very strong acid, producing running blisters.

EXCERPT FROM THE DECEMBER 8TH, 2008 NEWSLETTER

WHAT POISONWOOD JUICE DID TO MY SKIN
When I took the picture for the above essay I conducted a little experiment. I broke off a Poisonwood leaf and daubed a single droplet of juice onto the inside of my left wrist. The instant before I applied the juice I paused a moment, however, because exactly where I was about to daub the droplet there appeared a small, circular, white scar. This scar remained from when I conducted the same experiment with Poisonwood sap about 15 years ago when I was serving as a naturalist at a lodge in Belize. This time I put the droplet a little to the side of where I did earlier, so now I'll have two white spots.

You can see documentation of what happened to my wrist below:

Curiously, in Yokdzonot most people didn't regard Chakah/ Gumbo-Limbo as an antidote to Poisonwood sap. They used juice from bitter-oranges, which works perfectly, they said. This causes me to believe that Poisonwood's sap is caustic with a high pH, and that anything acidic, with a low pH, might neutralize the sap. However, belonging to the Poison Ivy Family, maybe Poisonwood also causes an allergic reaction, so I'd be careful experimenting with it. I'm not allergic to Poison Ivy so I couldn't test that aspect.