Mystery Plant! #722

John Nelson

Posted 5/10/23

By John Nelson

(Photo by Linda Lee.)

All of the maple trees of the world belong to a genus which has been named “Acer”. There are well over 100 different species, and practically all of them are native to the northern hemisphere. Maples play an important role in various ecological settings and forest types, and several species have considerable economic value. For instance, there is sugar maple, from which maple syrup comes… maybe that’s the best example. Otherwise, the wood of different maples is useful traditionally in making musical instruments, bowling pins (although I can’t imagine that some sort of plastic is now more commonly used for them), and just good for carving, too. Oh right, and also baseball bats. Maples are some of the most attractive canopy species in temperate forests, especially in the autumn, with really colorful foliage, one of the big reasons to spend time driving around in the mountains around here at “peak” season.

All maples are what we say are dioecious…this is a term we’ve used before, and it refers to a species whose individual plants are either staminate (“male”) and producing pollen, or pistillate (“female”), producing seeds. The leaves are always opposite, that is, two at a time on a twig. The leaves are simple, with a single blade, and usually equipped with lobes, most of the time angular, and often toothed. Think of the maple leaf on the Canadian flag. Or maybe a Japanese maple. The fruits are distinctive, and they are called “samaras”: each is equipped with an elongated wing which allows it to helicopter through the air once dropped.

Our Mystery Plant is a maple, but a bit of an oddball: its leaves are compound, with three leaflets. The twigs are green. It’s a tree which is frequent in most of the eastern USA, and it is generally found in damp forests.

And now, for some true confessions. Those of you who have ever gone on one of my botany field trips will remember that I am fond of being naughty with my students at times…I’ve enjoyed teasing them occasionally with little snippets of botany humor. I have, I shall admit, used our Mystery Plant as one of these subjects, announcing to the gathered class that this tree is an example of the astounding “POISON-IVY TREE”! And that the kids need but to gaze upon its fearsome trunk and bright green “let-it-be”  foliage to know and tremble! Of course, and as we have learned, our Mystery Plant has foliage which does look a lot like that of poison ivy. But poison ivy is never a tree…it often grows on trees, however, and large vines of it with their horizontally spreading stems can make it look like a tree itself. If you are fond of hikes in the woods, it’s a good idea to be confident about knowing what is and what is not poison ivy: mistakes involving its identifications can cause serious torment, if you are susceptible to its biochemical power. Our Mystery Plant, though, shouldn’t cause any problems.

[Answer: “Box elder,” Acer negundo]

John Nelson is the retired curator of the Herbarium at the University of South Carolina, in the Department of Biological Sciences. As a public service, the Herbarium offers free plant identifications. For more information, visit or email

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