Sunday, September 23, 2007

Poison Ivy and Box Elder

I was looking for something to draw in my nature journal while camping this weekend and noticed some poison ivy growing under a box elder at our campsite. The leaves are remarkably similar in shape, but I've never had trouble telling the difference. I learned to identify poison ivy as a kid and have always been able to spot it in all its forms, even without leaves. Still, it's tricky to describe the difference between poison ivy and box elder to someone by leaves alone. I thought drawing them might help me notice some differences. Can you tell which is poison ivy and which is box elder? I'll post the answer in a few days.

8 comments:

Anonymous said...

The one on the left is Poison Ivy. The one on the right is Box Elder.

Karina said...

I noticed I've been getting a lot of hits lately about poison ivy and box elder so I thought I should further elaborate on their differences.

Poison ivy often (but not always) has red where the three leaves meet. New leaves are also reddish.

Box elder leaves are more uniformly green, as are the young stems.

The other difference is very subtle: the widest part of the middle poison ivy leaflet tends to be 1/3 of the way down, whereas the widest part of a box elder leaflet tends to be 2/3 of the way down. You can see this in my drawings.

Happy hiking!

Resume said...

The easiest way to tell them apart is in the leaf arrangement on the stem. Poison ivy has alternate leaf arrangement and box elder has opposite leaf arrangement.

Karina said...

Thank you Resume! So obvious I should have noticed that and mentioned it myself.

Keith Conover said...

Great drawing, and great explanation. I have a handout on Poison Ivy for when I'm lecturing (I'm an academic emergency physician). I have been considering adding something on telling Box Elder (especially right now in the spring, the immature seedlings) from Poison Ivy, and your picture would be great in my handout. May I have permission to use it (with attribution)? Current handout at http://www.conovers.org/ftp/ and then scroll down to Poison Ivy.pdf Thanks

Karina said...

Hi Keith,
Yes! You may use it. Your current handout looks great! Thanks for your interest. If you need a better image, please send me an email.
Karina

Heather said...

If I send you a picture, can you tell me if it is box elder or poison ivy? I've looked at several different sites and still can't figure it out.

Karina said...

Hi Heather! Probably, yes. Close ups of the leaves as well as a view of the whole plant will help. You could also try something like iNaturalist.org or projectnoah.org for help.