When I was a kid, my family went to stay at our friends’ cabin, up in the mountains of New Mexico. It was a nice place, deep in the woods. We spent lots of time running around the area, climbing over the streams, splashing in the water, and crashing through the undergrowth. Now, we spent plenty of time outdoors, so we knew to watch out for things like poison ivy and poison oak. There wasn’t too much of that where we were anyways. However, I distinctly remember a moment when, while walking through a particularly overgrown area, my hand brushed up against a plant, and I felt a stinging sensation. I looked at my hand, but I did not see any cut. However, later on I did notice that I somehow developed a bit of a scar on my finger where it had brushed against this plant. In fact, that scar is still there, all these many years later. Although I have been curious about that plant throughout the years, I’ve never thought to look into it….until now, that is.
As it turns out, there are a whole bunch of plants that can be toxic to the touch. Poison ivy and poison oak are just two of the most well-known ones. Based on my fuzzy memories of the incident, I believe the plant I came into contact with was cow parsnip, Heracleum maximum. Some other species of this plant genus, are known collectively as hogweed. This plant can be found all throughout the northern hemisphere, and there are species native to North America, Europe, Asia, and the Middle East. They are in the same plant family as carrots and parsnips.
These plants are infamous for containing chemicals called furanocoumarins. This special kind of chemical serves as a defense mechanism to protect the plant against insects and mammals which may want to eat it. When this chemical comes into contact with animal cells and is exposed to ultraviolet light, it can penetrate the cell’s nucleus and bond with the DNA inside. This causes the cell to die, and results in inflammation of the area. This is known as phytophotodermatitis (I don’t recommend looking at that page if you don’t want to see some pretty severe inflammation). Over the course of the next few days, large blisters will form on the affected area. These blisters may also become very dark, as a result of increased melanin production triggered by the furanocoumarins. This is known as hyperpigmentation. If left untreated, the skin in the area may develop permanent hyperpigmentation (staying darker), or hypopigmentation (becoming lighter).
While I think this cow parsnip is a likely culprit for my scar. I do not remember much blistering, but I barely touched the plant, and it only affected a tiny area on my finger. This area may resemble a scar due to the hypopigmentation left behind. Luckily, cow parsnip and other members of the Heracleum genus are not too common. However, they are native to all of the US and Canada, and they are a significant problem on the east coast, where people playing outside have to watch out for them. Some members of this family can grow to be over 14 feet tall, so they’re a bit easier to spot than poison ivy or poison oak. Here is a good reference for identifying hogweed.
If you do come into contact with such a plant, make sure to wash your skin very thoroughly with soap and water. Because furanocoumarins react to ultraviolet light, keep your skin covered and out of the light for at least 48 hours. And make sure to contact a doctor if you think you have come into contact with it. Playing outdoors is really great, but make sure to stay safe this summer!
If you know anyone who would like to receive these, please have them send an email to [email protected]. And if you would rather pick flowers without worrying about dangerous chemicals, let me know and I can take you off the list.