Mystery Plant! #739
By John Nelson
When it rains it pours, and I don’t mean that recent hurricane.
Among the plant identification requests we got last week here in the Herbarium, there were three separate questions about this very odd plant. I can’t quite figure out if it is suddenly being noticed now, for some reason, or if it really is a recent introduction, establishing itself quickly. I’m inclined to go with the first idea.
This plant is placed by botanists in what we call the “mulberry” family (or Moraceae), which, sure enough, contains the familiar mulberries. The mulberry family is a large group, containing many thousands of additional species, most of which are woody, tree or shrubs, and found in the tropics. There are some important tropical tree members yielding timber, and of course, everyone knows of figs…nearly 1,000 different species, including that potted rubber-tree in your dentist’s waiting room. Those of you who are fans of “Mutiny on the Bounty” will remember the poor little breadfruit plants that got tossed overboard: breadfruit is another tropical species –with edible fruits– in the mulberry family.
But our Mystery plant is neither mulberry, fig, nor breadfruit. This is a pretty darn strange plant for our area, introduced from eastern Asia. It is potentially a tree, a deciduous one, although most often it is seen as a shrub. It’s a slow grower, and given enough time can attain considerable size as an honest-to-goodness tree. It has hard, tough wood, and its roots are rather yellowish. Of particular interest will be the very stout thorns that are produced on some branches: they can be dangerous. The leaves are handsome, dark green and glossy. Young leaves are somewhat peculiar in having 3 prominent shoulders, or lobes, toward the tip. The plants are either male or female…that is, bearing either staminate or pistillate flowers…not both. (The term, of course, for such a species is “dioecious”.) Whether male or female, the flowers are small and inconspicuous, held in little roundish balls in the spring. In the fall, the female flowers’ ovaries swell into a fleshy mass, which takes on a sort of strawberry appearance, at first green, and eventually turning red or orange. When the fruit gets ripe and mushy, it’s ready to eat. (I’ve been able to try it once. It was OK.) There are actually several named cultivars which are available. I understand that there is also a seedless variety, one that supposedly won’t ever produce seedlings.
The leaves, thorns, and fruits that are produced by our mysterious plant might make you think of another mulberry-ish relative, the much more widespread “Osage-orange”, which is also seen in the Southeast. Osage-orange, however, is normally a smaller plant, with smaller leaves, and it produces a large, green, globose fruit, that looks sort of like a brain…and which is NOT edible. As long as you have the fruits of both species, so characteristic of each, you won’t have any trouble telling the two apart. Without the fruits, though, you might need a botanist’s help!
[Answer: “Strawberry tree,” “Melonberry”, Maclura tricuspidata]
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 www.herbarium.org or email firstname.lastname@example.org.
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