Poison Oak in Michigan? Yeah, right.
Michigan's Toxicodendrons do not include Poison Oak (T. pubescens)
I received some great feedback from my first Tom’s Tales podcast, describing the difference between black flies and stable flies. And someone suggested “Hey tom how about the difference between Poison Ivy, Poison Oak, and Poison sumac”
Challenge accepted!
Again, I am a biologist & I am from Michigan and have spent way too much time outdoors. And let’s just say I’ve been intimate with poison ivy & poison sumac, but I’ve never cheated on those two with poison oak.
And that leads me to my taxonomy refresher. Taxonomy is the system scientists use to organize, catalog & name organisms. Each organism has its own unique “scienitfic name”. It has a first name and a last name, called Genus and species. Scientists use Latin words, suffixes & prefixes and frankly just invent words on occasion to name organisms. These scientific names, say Gallus gallus, are universally used around the world. When I say Gallus gallus to a scientist in Germany, China, and South Sudan, they all know I’m talking about your common barnyard chicken.
Common names are what you call the Gallus gallus locally. I call it a chicken. In Mexico, it’s pollo. In United Arab Emirates where I currently live, FUR-ooosh.
Ok, back to Poison Ivy, Sumac and Oak. These are the common names, of course. Scientific names for each are
Poison Oak Toxicodendron pubescens
Poison Ivy T. radicans & T. rydbergii (former climbs & southern, latter ground cover & more northern)
And, did you know they are in the Cashew family? Yes, they are but don’t eat them.
Let’s start with Poison Ivy. You know, leaves of three, let it be? If you followed this rule religiously, you’d avoid about ¼ of all plants.
In Michigan, there are two species. T. radicans lives in the southern lower and has hairy stems allowing it to climb trees as a vine. T. rydbergii is a ground cover and lives in the NLP and UP.
Both have three leaves and what I have found is folks need to see this stuff a hundred times before they can get their head around what it is as it does look like so many other plants. One plant it looks like is Virginia Creeper, which has five leaves. Five does not equal three… unless you are from Ohio.
The best description I can give you is the leaves look “oily”. If you are familiar with leaves having “teeth”, they will have a few teeth and usually one or two of the leaves will have one large tooth that looks like a thumb. That is the giveaway for me. If the teeth are numerous and or uniform, it probably isn’t poison ivy.
Poison Sumac is a shrub that lives in swamps. And I’m talking mucky swamps with 2 feet of muck and water. Unless you go tromping through these habitats you probably won’t encounter it. Many people vilify sumac in general as being Poison Sumac but if it is on dry ground, it isn’t poison sumac. Where you will find it is walking on a boardwalk in a wetland. Its form looks like sumac and it has compound leaves which have no teeth. The shrub looks “spindly” to me. A respectable nature trail caretaker will make sure this stuff isn’t anywhere near the boardwalk. They produce white berries in the fall.
Now for our last plant, Toxicodendron pubescens. “Hairy toxic leaf” in Latin. And I am here to tell you no self-respecting Michigan botanist or biologist recognizes Poison Oak as a plant that is native to Michigan. I repeat, Poison oak, Toxicodendron pubescens, is native in the southeast and Florida. It does not grow here. Yeah, yeah, I know people will say it does but THEY ARE WRONG! Ok, well, let me rephrase. No Michigan botanist recognizes the common name Poison Oak associated with any plant that grows here. Remember, ask the person to give you the scientific name of the plant they are referencing.
So, now you have this scientific name, now what do you do? Well, you are in luck! The ultimate plant resource is Michiganflora.net Go ahead, enter “poison oak” into the search engine. What are the results? Well, there are none because Poison oak doesn’t live in Michigan! The next time one of your friends says poison oak lives in Michigan, make a wager, and utilize this website.
So how do we protect ourselves from these plants? Of course, knowing what they are helps. Second, about ⅓ of the population is immune to these plants and their oil, urushiol (OOH RUE SHE ALL). The rest of us? Well, wear long pants and you can even put on a preventative, brand name Technu. You can use the same after you’ve been exposed. Otherwise, if you have been exposed, cold water flushed over the skin as soon as you can, with soap, is your best bet to prevent getting a rash.
Toxicodendrons. Get to know them and learn how to ID them so as to avoid them. As I mentioned, use Michiganflora.net for identifying plants. You can use common or scientific names. This database is the product of the University of Michigan, and, is based on the work of Edward Voss, who wrote a three-volume set “Michigan Flora”. Anyone claiming to be a Michigan Botanist has this set of books, yours truly as well. If you are new to plant id, get a copy of Newcomb’s Wildlflower guide for Eastern North America. Very easy for a nonbotanist to use.
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